But I couldn't have absorbed much more scintillation just then anyway.
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This is light, or scintillation, and it's what the project looks for.
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Most sailed through, to be recorded by a scintillation screen beyond the foil.
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Once I've sourced and sorted, I look for sparkle, life, light, brilliance, scintillation, and the overall beauty.
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One of the issues right now with using Facebook's drones to transmit internet is scintillation effects, also known as twinkling.
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But even if the national scintillation of these stories faded quickly, it's worth remembering that their effects on local communities will endure.
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So the group of researchers decided to produce their own current measurements by physically plotting radiation maps of all six islands using gamma scintillation detectors and GPS trackers.
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Physicist Jocelyn Bell Burnell discovered pulsars in 1967, when she noticed a radio signal varying with a 1.34-second period in data from the Interplanetary Scintillation Array at the Mullard Radio Astronomy Observatory.
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But the desire is both unconvincing and generic: We don't get any real specificity of romantic struggle or scintillation in his words or hers, and I definitely didn't detect anything that sounds even a little bit like longing in their voices.
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Even so, scintillation design has room for improvement as do other options for neutron detection besides scintillation.
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Scintillation neutron detectors include liquid organic scintillators, crystals,Example crystal scintillator based neutron monitor. plastics, glass and scintillation fibers.
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Twinkling, or scintillation, is a generic term for variations in apparent brightness or position of a distant luminous object viewed through a medium.Wang, Ting-I; Williams, Donn; "Scintillation technology bests NIST". , InTech, May 1, 2005. If the object lies outside the Earth's atmosphere, as in the case of stars and planets, the phenomenon is termed astronomical scintillation; within the atmosphere, the phenomenon is termed terrestrial scintillation.
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In liquid scintillation counting, a small aliquot, filter or swab is added to scintillation fluid and the plate or vial is placed in a scintillation counter to measure the radioactive emissions. Manufacturers have incorporated solid scintillants into multi-well plates to eliminate the need for scintillation fluid and make this into a high-throughput technique. A gamma counter is similar in format to scintillation counting but it detects gamma emissions directly and does not require a scintillant. A Geiger counter is a quick and rough approximation of activity.
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Sofieva, V. F.; Sofieva, A. S.; et al. "Reconstruction of internal gravity wave and turbulence parameters in the stratosphere using GOMOS scintillation measurements". Journal of Geophysical Research 112.VanCleave, Janice; "Stellar Scintillation: Twinkling Stars".
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Radioactivity is usually measured in these procedures using a scintillation counter.
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The process of scintillation is one of luminescence whereby light of a characteristic spectrum is emitted following the absorption of radiation. The emitted radiation is usually less energetic than that absorbed. Scintillation is an inherent molecular property in conjugated and aromatic organic molecules and arises from their electronic structures. Scintillation also occurs in many inorganic materials, including salts, gases, and liquids.
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Counting efficiency varies for different isotopes, sample compositions and scintillation counters. Poor counting efficiency can be caused by an extremely low energy to light conversion rate, (scintillation efficiency) which, even optimally, will be a small value. It has been calculated that only some 4% of the energy from a β emission event is converted to light by even the most efficient scintillation cocktails.
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Scintillation is a flash of light produced in a transparent material by the passage of a particle (an electron, an alpha particle, an ion, or a high- energy photon). See scintillator and scintillation counter for practical applications.
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Scintillation crystal surrounded by various scintillation detector assemblies. Extruded plastic scintillator material fluorescing under a UV inspection lamp at Fermilab for the MINERνA project A scintillator is a material that exhibits scintillation, the property of luminescence, when excited by ionizing radiation. Luminescent materials, when struck by an incoming particle, absorb its energy and scintillate (i.e. re-emit the absorbed energy in the form of light).
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This led him to propose, and secure funding for, the construction of the Interplanetary Scintillation Array, a large array radio telescope at the Mullard Radio Astronomy Observatory (MRAO), Cambridge to conduct a high time- resolution radio survey of interplanetary scintillation.
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Gamma-Ray Scintillation Detector for Neutron Activation Analysis with ATF Forensic Laboratory Analyst in Washington, D.C. (1966) There are a number of detector types and configurations used in NAA. Most are designed to detect the emitted gamma radiation. The most common types of gamma detectors encountered in NAA are the gas ionisation type, scintillation type and the semiconductor type. Of these the scintillation and semiconductor type are the most widely employed.
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Scintillation probe being used to measure surface radioactive contamination. The probe is held as close to the object as practicable Scintillation counters are used to measure radiation in a variety of applications including hand held radiation survey meters, personnel and environmental monitoring for radioactive contamination, medical imaging, radiometric assay, nuclear security and nuclear plant safety. Several products have been introduced in the market utilising scintillation counters for detection of potentially dangerous gamma-emitting materials during transport. These include scintillation counters designed for freight terminals, border security, ports, weigh bridge applications, scrap metal yards and contamination monitoring of nuclear waste.
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The scientific payload also included two gas-discharge Geiger counters, a sodium- iodide scintillation counter, and a Cherenkov detector. The upper stage of the rocket contained a scintillation counter and of sodium for a gas-dispersion experiment. The spacecraft weighed at launch.
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An alternative method is to use internal liquid scintillation counting, where the sample is mixed with a scintillation cocktail. When the light emissions are then counted, some machines will record the amount of light energy per radioactive decay event. Due to the imperfections of the liquid scintillation method (such as a failure for all the photons to be detected, cloudy or coloured samples can be difficult to count) and the fact that random quenching can reduce the number of photons generated per radioactive decay, it is possible to get a broadening of the alpha spectra obtained through liquid scintillation. It is likely that these liquid scintillation spectra will be subject to a Gaussian broadening, rather than the distortion exhibited when the layer of an active material on a disk is too thick.
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Institute for Scintillation Materials of NAS of Ukraine is a Ukrainian leading research centre specializing in luminescent and scintillation materials research and development and can be ranked in the top of the European and international research organizations working in the area of radiation detection.
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Particle interactions in the liquid target produce scintillation and ionization. The prompt scintillation light produces 178 nm ultraviolet photons. This signal is detected by the PMTs, and is referred to as the S1 signal. This technique has proved sensitive enough to detect single photoelectrons.
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Arago later used a similar argument to explain the colors in the scintillation of stars.Silliman (1967, p. 163) and Frankel (1976, p. 156) give the date of Arago's note on scintillation as 1814; but the sequence of events implies 1816, in agreement with Darrigol (2012, pp. 201,290).
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The earliest sensors were scintillation detectors, with photomultiplier tubes excited by (typically) cesium iodide crystals. Cesium iodide was replaced during the 1980s by ion chambers containing high-pressure xenon gas. These systems were in turn replaced by scintillation systems based on photodiodes instead of photomultipliers and modern scintillation materials (for example rare-earth garnet or rare-earth oxide ceramics) with more desirable characteristics. Initial machines would rotate the X-ray source and detectors around a stationary object.
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He was also one of the first scientists to explain the scintillation (twinkling) of stars at night.
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CeBr3-doped lanthanum bromide single crystals are known to exhibit superior scintillation properties for applications in the security, medical imaging, and geophysics detectors. Undoped single crystals of CeBr3 have shown promise as a γ-ray scintillation detector in nuclear non-proliferation testing, medical imaging, environmental remediation, and oil exploration.
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Detection and measurement of surface contamination of personnel and plant is normally by Geiger counter, scintillation counter or proportional counter. Proportional counters and dual phosphor scintillation counters can discriminate between alpha and beta contamination, but the Geiger counter cannot. Scintillation detectors are generally preferred for hand held monitoring instruments, and are designed with a large detection window to make monitoring of large areas faster. Geiger detectors tend to have small windows, which are more suited to small areas of contamination.
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The scientific activities (Present) The interaction processes of electromagnetic radiation with condensed matter. Ceramic composite, single-crystal, film, liquid and plastic materials for various functional purposes. Scintillation Materials, luminescence, radiation instrumentation. R&D; head Methods’ development of the organization scintillation properties for single crystals on the basis of rare earth oxides.
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Liquid argon is used as the target for neutrino experiments and direct dark matter searches. The interaction between the hypothetical WIMPs and an argon nucleus produces scintillation light that is detected by photomultiplier tubes. Two-phase detectors containing argon gas are used to detect the ionized electrons produced during the WIMP–nucleus scattering. As with most other liquefied noble gases, argon has a high scintillation light yield (about 51 photons/keV ), is transparent to its own scintillation light, and is relatively easy to purify.
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LENA (Low Energy Neutrino Astronomy) is a liquid scintillation detector with a mass about 50 kton. Its cylindrical shaped tank with about 100 meters height and 30 meters diameter. The actual scintillation volume is surrounded by nylon barrier and buffer volume. Additionally the buffer volume is surrounded by a pure water volume.
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In the late 1970s, the radio source 4C21.53 captured the attention of radio astronomers, "because of its anomalously high level of interplanetary scintillation." As interplanetary scintillation is associated with compact radio sources, the interplanetary scintillation observations suggested that 4C21.53 might be a supernova remnant, but a pulsar survey carried out at Arecibo Observatory in 1974 by Russell Hulse and Joseph Taylor in the region did not discover a pulsar associated with 4C21.53. With the lack of success in finding a pulsar in the region, other explanations for the scintillation were explored, including suggestion of entirely new classes of objects. After realizing in 1982 that previous searches for a pulsar in the region of 4C21.53 were not sensitive to periods short enough to produce the observed scintillation, Don Backer initiated a search in the area that would be sensitive to a wide range of pulse periods and dispersion measures, including very short periods.
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He published over a hundred scientific papers in the course of his career, and edited a book about scintillation phenomena.
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G. Zdesenko et al., "Scintillation properties and radioactive contamination of CaWO4 crystal scintillators" Nucl. Instrum. Meth. A 538 (2005) 657.
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The detection mechanism of LENA will be the photomultiplier tubes, which are designed to cover partly the walls between buffer volume and water volume. The scintillation light produced in scintillation volume will be detected with those photomultiplier tubes. LENA's aim is to study low energy neutrinos originated by supernova explosions, Sun and Earth's interior.
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1964 - Introduced first dual head rectilinear scanner 1967 - developed scan minification principle 1968 - first to offer 750 cm/min scanning speed. 1972 - Introduced 37 tube scintillation camera 1974 - introduced large field scintillation camera to US market. 1975 - Introduced 37 tube large field mobile camera. Introduced DeltaScan, a high resolution (256 x 256) matrix whole body computed tomography scanner.
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JVC's Science Fair Projects, May 2, 2010. Scintillation effects are always much more pronounced near the horizon than near the zenith (directly overhead),"Scintillation or Atmospheric Boil", noaa.gov. since light rays near the horizon must penetrate a denser layer of and have longer paths through the atmosphere before reaching the observer. Atmospheric twinkling is measured quantitatively using a scintillometer.
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Alpha scintillation probe under calibration The most commonly used hand-held survey meters are the scintillation counter, which is used in the measurement of alpha, beta and neutron particles; the Geiger counter, widely used for the measurement of alpha, beta and gamma levels; and the ion chamber, which is used for beta, gamma and X-ray measurements.
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Laboratory equipment for determination of γ-radiation spectrum with a scintillation counter. The output from the scintillation counter goes to a Multichannel Analyzer which processes and formats the data. The main components of a gamma spectrometer are the energy-sensitive radiation detector and the electronic devices that analyse the detector output signals, such as a pulse sorter (i.e., multichannel analyzer).
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Gamma counters are usually scintillation counters. In a typical system, a number of samples are placed in sealed vials or test tubes, and moved along a track. One at a time, they move down inside a shielded detector, set to measure specific energy windows characteristic of the particular isotope. Within this shielded detector there is a scintillation crystal that surrounds the radioactive sample.
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Sodium iodide activated with thallium, NaI(Tl), when subjected to ionizing radiation, emits photons (i.e., scintillate) and is used in scintillation detectors, traditionally in nuclear medicine, geophysics, nuclear physics, and environmental measurements. NaI(Tl) is the most widely used scintillation material. The crystals are usually coupled with a photomultiplier tube, in a hermetically sealed assembly, as sodium iodide is hygroscopic.
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SSIES, or the Special Sensors-Ions, Electrons, and Scintillation thermal plasma analysis package is a suite of instruments built by the William B. Hanson center for Space Sciences at the University of Texas at Dallas and flown on a number of the DMSP satellites. SSIESS includes a Retarding Potential Analyzer (RPA), and Ion Drift meter (IDM), a scintillation meter, and a Langmuir probe.
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Scintillation materials are used for ambient gamma dose measurement, though a different construction is used to detect contamination, as no thin window is required.
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Cerium(III) bromide is an inorganic compound with the formula CeBr3. This white hygroscopic solid is of interest as a component of scintillation counters.
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Those holes and electrons are captured successively by impurity centers exciting certain metastable states not accessible to the excitons. The delayed de-excitation of those metastable impurity states again results in scintillation light (slow component). BGO (bismuth germanium oxide) is a pure inorganic scintillator without any activator impurity. There, the scintillation process is due to an optical transition of the ion, a major constituent of the crystal.
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The ratio of ionization over scintillation from electron and gamma interactions is different than WIMP scattering produces. The 39Ar background is therefore well distinguishable, with a precise determination of the ionization/scintillation ratio. As an alternative, the use of depleted argon from underground wells is being considered. Neutrons emitted by detector components and by materials surrounding the detector interact with argon in the same way as WIMPs.
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Strontium iodide (SrI2) is a salt of strontium and iodine. It is an ionic, water-soluble, and deliquescent compound that can be used in medicine as a substitute for potassium iodide . It is also used as a scintillation gamma radiation detector, typically doped with europium, due to its optical clarity, relatively high density, high effective atomic number (Z=48), and high scintillation light yield. In recent years, europium-doped strontium iodide (SrI2:Eu2+) has emerged as a promising scintillation material for gamma-ray spectroscopy with extremely high light yield and proportional response, exceeding that of the widely used high performance commercial scintillator LaBr3:Ce3+.
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A scintillator is a material which exhibits the property of luminescence when excited by ionizing radiation. Luminescent materials, when struck by an incoming particle, such as an X-ray photon, absorb its energy and scintillate, i.e. reemit the absorbed energy in the form of a small flash of light, typically in the visible range. Scintillation crystal surrounded by various scintillation detector assemblies The scintillation X-ray detector (XC) aboard Vela 5A and its twin Vela 5B consisted of two 1 mm thick NaI(Tl) crystals mounted on photomultiplier tubes and covered by a 0.13 mm thick beryllium window. Electronic thresholds provided two energy channels, 3-12 keV and 6-12 keV.
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The main directions of scientific activities of Boris Grinyov are such as: the fundamental properties of scintillation materials studying, searching for new scintillators, instruments and devices developing based on new scintillators for applications in various fields. . B. Grinyov’s works to a large extent, determine the level of modern world technologies for the production and processing of scintillation and luminescent materials. Research conducted by B. Grinyov enabled to develop industrial automated technology of growing the large highly transparent optical crystal with a diameter up to 600 mm, ideal scintillation single crystals of up to 520 mm in diameter and weighing more than 500 kg. For the high-energy physics experiments the production technology of plastic scintillators were developed with weighing up to 1,000 kg with a high bulk transparency (up to 4 m), scintillator plates of up to 3.7 m, unique scintillation strips and combined complex shape detectors.
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LUX is developing similar systems that have set improved limits. Signal from ZEPLIN-III two- phase xenon detector. The fast scintillation pulse (S1) is generated promptly by scintillation in the liquid; a larger, delayed pulse (S2) is obtained once the ionisation drifted from the interaction site is emitted into the thin gas phase above the liquid. The insets below the signal traces show Monte Carlo simulation of the optical signals.
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In gases, the scintillation process is due to the de-excitation of single atoms excited by the passage of an incoming particle (a very rapid process: ≈1 ns).
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It appears especially at seaside level. Scintillation and glint are actually two manifestations of the same phenomenon and are most properly linked to one another in target modeling.
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Harmut Kallmann (5 February 1896 – 11 June 1978) was a German physicist. He is known for his work on the scintillation counter for the detection of gamma rays.
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The term scintillation brilliance is applied to the number and arrangement of light reflections from the internal facets; that is, the degree of "sparkle" seen when the stone or observer moves. Scintillation is dependent on the size, number, and symmetry of facets, as well as on quality of polish. Very small stones will appear milky if their scintillation is too great (due to the limitations of the human eye), whereas larger stones will appear lifeless if their facets are too large or too few. A diamond's fire is determined by the cut's crown height and crown angle (the crown being the top half of the stone, above the girdle), and the size and number of facets that compose it.
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Hand-held large area alpha scintillation probe under calibration with a plate source. Hand-held scintillation counter reading ambient gamma dose. The position of the internal detector is shown by the cross Radioactive contamination monitors, for area or personal surveys require a large detection area to ensure efficient and rapid coverage of monitored surfaces. For this a thin scintillator with a large area window and an integrated photomultiplier tube is ideally suited.
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Each surface detector has an assembled weight of 250 kg and consists of a power supply, two layers of scintillation detectors and electronics. Power is generated by a 120W solar panel and stored in a sealed lead-acid battery. The system has the capacity to operate for one week in complete darkness. Each scintillation detector layer is made of extruded plastic scintillator that is 1.2 cm thick and has an area of 3m2.
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The SPA technique is dependent on the energy conversion of radioactive decay, which releases light photons which can be detected via the use of some devices such as the photomultiplier tubes of scintillation counters or CCD imagers. This is a very popular technique in practices that require detecting and quantifying radioactivity.Homogeneous Proximity Tyrosine Kinase Assays: Scintillation Proximity Assay versus Homogeneous Time-Resolved Fluorescence. Analytical Biochemistry Volume 269, Issue 1, 10 April 1999, Pages 94-104.
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A more complete theory of scintillation saturation, that gives Birks' law when only unimolecular de-excitation is included, can be found in a paper by Blanc, Cambou, and De Laford.
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Semin Nucl Med 1996;26:180-190. and (1958) Hal Anger developed the gamma scintillation camera,Gottschalk A: The early years with Hal Anger. Semin Nucl Med 1996; 26:171-179.
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There are several hydrates, La3Br·x H2O, of the salt also known. It is often used as a source of lanthanum in chemical synthesis and as a scintillation material in certain applications.
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In these, the sodium iodide crystals are doped with a small amount of thallium to improve their efficiency as scintillation generators. Some of the electrodes in dissolved oxygen analyzers contain thallium.
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93-96 The drift chambers used in the experiment originate from the DELPHI- experiment at CERN. Additionally the limited streamer tubes and plastic scintillation detectors are part of the measurement stations.
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Condensed noble gases, most notably liquid xenon and liquid argon, are excellent radiation detection media. They can produce two signatures for each particle interaction: a fast flash of light (scintillation) and the local release of charge (ionisation). In two-phase xenon – so called since it involves liquid and gas phases in equilibrium – the scintillation light produced by an interaction in the liquid is detected directly with photomultiplier tubes; the ionisation electrons released at the interaction site are drifted up to the liquid surface under an external electric field, and subsequently emitted into a thin layer of xenon vapour. Once in the gas, they generate a second, larger pulse of light (electroluminescence or proportional scintillation), which is detected by the same array of photomultipliers.
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However, the experimentalists alluded to the fact, that calorimetric tests with 10-GeV electrons were executed already in 1969. There, copper was used as beam dump, and an accuracy of 1% was achieved. In modern calorimeters called electromagnetic or hadronic depending on the interaction, the energy of the particle showers is often measured by the ionization caused by them. Also excitations can arise in scintillators (see scintillation), whereby light is emitted and then measured by a scintillation counter.
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In astronomy, interplanetary scintillation refers to random fluctuations in the intensity of radio waves of celestial origin, on the timescale of a few seconds. It is analogous to the twinkling one sees looking at stars in the sky at night, but in the radio part of the electromagnetic spectrum rather than the visible one. Interplanetary scintillation is the result of radio waves traveling through fluctuations in the density of the electron and protons that make up the solar wind.
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Its peak scintillation wavelength is 480 nm (with emission range between 380-660 nm), and efficiency of 13000 photons/MeV. It has a relatively high light yield, its light output is about 40% of NaI(Tl), but the time of scintillation is quite long (12−15 μs). It is often used in computed tomography. Combining the scintillator crystal with externally applied piece of boron carbide allows construction of compact detectors of gamma rays and neutron radiation.
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In some situations, other elements such as boron, indium, gold, or dysprosium may be used or materials such as LiF scintillation screens where the conversion screen absorbs neutrons and emits visible light.
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PPX is mixed with a known quantity of labeled polyphosphate, and the hydrolysis reaction is stopped with perchloric acid (HClO4). The amount of remaining labeled polyphosphate is then measured by liquid scintillation counting.
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One method for testing of (and measuring) many alpha emitters is to use alpha- particle spectroscopy. For methods of gamma rays and beta particles, please see gamma spectroscopy and liquid scintillation counting respectively.
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Critically for WIMP searches, the ratio between the two response channels (scintillation and ionisation) allows the rejection of the predominant backgrounds for WIMP searches: gamma and beta radiation from trace radioactivity in detector materials and the immediate surroundings. WIMP candidate events produce lower ionisation/scintillation ratios than the more prevalent background interactions. The ZEPLIN programme pioneered the use of two-phase technology for WIMP searches. The technique itself, however, was first developed for radiation detection using argon in the early 1970s.
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The neutron flux at the imaging focal plane is measured by a CCD imaging array with a neutron scintillation screen in front of it. The scintillation screen is made of zinc sulfide, a fluorescent compound, laced with lithium. When a thermal neutron is absorbed by a lithium-6 nucleus, it causes a fission reaction that produces helium, tritium and energy. These fission products cause the ZnS phosphor to light up, producing an optical image for capture by the CCD array.
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Strong dependence of decay time on the temperature in BGO scintillator is used for remote monitoring of temperature in vacuum environment. The coupled PMTs also exhibit temperature sensitivity, and can be damaged if submitted to mechanical shock. Hence, high temperature rugged PMTs should be used for high-temperature, high- vibration applications. The time evolution of the number of emitted scintillation photons N in a single scintillation event can often be described by linear superposition of one or two exponential decays.
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Scintillography is mainly used in scintillation cameras in experimental physics. For example, huge neutrino detection underground tanks filled with tetrachloroethylene are surrounded by arrays of photo detectors in order to capture the extremely rare event of a collision between the fluid's atoms and a neutrino. Another extensive use of scintillography is in medical imaging techniques which use gamma ray detectors called gamma cameras. Detectors coated with materials which scintillate when subjected to gamma rays are scanned with optical photon detectors and scintillation counters.
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Hand-held large area alpha scintillation probe under calibration using a plate source in close proximity to the detector. Large area scintillation counters used for surface radioactive contamination measurements use plate or planar radioactive sources as calibration standards. The Surface Emission Rate (SER), not the source activity, is used as a measure of the rate of particles emitted from the source of radiation. The SER is the true emission rate from the surface, which is usually different to the activity.
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The six bars in each octant half overlapped to avoid having any uninstrumented regions. The scintillation photons were detected by photomultiplier tubes. Each bar was 2.03 m × 0.312 m× 0.025 m.CLEO I NIM p.
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By positioning Light tubes strategically, using filters and other light optics means, the SE can again be separated from the BSE and corresponding images formed. This form of detection is referred as scintillation-GDD.
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Although sometimes facilitated by higher incoming neutron energies, neutron detection is generally a difficult task, for all the reasons stated earlier. Thus, better scintillator design is also in the foreground and has been the topic of pursuit ever since the invention of scintillation detectors. Scintillation detectors were invented in 1903 by Crookes but were not very efficient until the PMT (photomultiplier tube) was developed by Curran and Baker in 1944. The PMT gives a reliable and efficient method of detection since it multiplies the detection signal tenfold.
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In the case of neutron detectors, high efficiency is gained through the use of scintillating materials rich in hydrogen that scatter neutrons efficiently. Liquid scintillation counters are an efficient and practical means of quantifying beta radiation.
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Lev Landau and his student Isaak Pomeranchuk headed the theory division of the institute in 1945–46 and 1946–66, respectively. At ITEP, Alikhanov led research on and advanced scintillation techniques, bubble chambers, and spark chambers.
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Zang-Hee Cho, Ph.D, is a Korean neuroscientist who developed the first Ring- PET scanner and the scintillation detector BGO. More recently, Cho developed the first PET-MRI fusion molecular imaging device for neuro-molecular imaging.
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From this the EXOSAT Medium Energy Slew Survey catalog was created. From the use of the Gas Scintillation Proportional Counter (GSPC) on board EXOSAT, a catalog of iron lines from some 431 sources was made available.
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This field cage maintains a uniform electric field between the cathode and the anode, so that drift electron trajectories deviate as little as possible from the shortest path between the point of ionization and the anode plane. This is intended to prevent distortion of particle trajectory during event reconstruction. A light-collection system often accompanies the basic LArTPC as a means of extracting more information from an event by scintillation light. It can also play an important role in triggering, because it collects scintillation light only nanoseconds after the particle passes through the detector.
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A number of hypotheses have been advanced as to the source and nature of the Wow! signal. None of them have achieved widespread acceptance. Interstellar scintillation of a weaker continuous signal—similar in effect to atmospheric twinkling—could be an explanation, but that would not exclude the possibility of the signal being artificial in origin. The significantly more sensitive Very Large Array did not detect the signal, and the probability that a signal below the detection threshold of the Very Large Array could be detected by the Big Ear due to interstellar scintillation is low.
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As the scintillation light produced is of short wavelength (128 nm) a wavelength-shifting film was used to absorb the ultraviolet scintillation light and re-emit in the visible spectrum (440 nm) enabling the light to pass through ordinary windows without any losses and eventually be detected by the PMTs. DEAP-1 demonstrated good pulse-shape discrimination of backgrounds on the surface and began operation at SNOLAB. The deep underground location reduced unwanted cosmogenic background events. DEAP-1 ran from 2007 to 2011, including two changes in the experimental setup.
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The other common technology used for measuring activity is liquid scintillation counting, which was invented in 1950, but which had to wait until the early 1960s, when efficient methods of benzene synthesis were developed, to become competitive with gas counting; after 1970 liquid counters became the more common technology choice for newly constructed dating laboratories. The counters work by detecting flashes of light caused by the beta particles emitted by as they interact with a fluorescing agent added to the benzene. Like gas counters, liquid scintillation counters require shielding and anticoincidence counters.Theodórsson (1996), p. 24.
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X-ray tubes used for continuous-duty operation in fluoroscopy and CT imaging equipment may use a focused cathode and a rotating anode to dissipate the large amounts of heat thereby generated. These are housed in an oil-filled aluminum housing to provide cooling. The photomultiplier tube is an extremely sensitive detector of light, which uses the photoelectric effect and secondary emission, rather than thermionic emission, to generate and amplify electrical signals. Nuclear medicine imaging equipment and liquid scintillation counters use photomultiplier tube arrays to detect low-intensity scintillation due to ionizing radiation.
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The circular, quasi-random antenna distribution has been chosen to optimise the beam pattern of the array. The LBA array is used for solar astronomy, general radio astronomy, ionospheric scintillation, multi-frequency riometry and other passive receiver experiments.
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The chambers were triggered by requiring hits in scintillation counters at each end. This trigger rejected essentially all elastic and diffractive elements. The streamer chamber tracks were photographed by six cameras, and the tracks were measured, reconstructed and analyzed.
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However, recent results (considered invalid by the original investigators) obtained with unshielded scintillation neutron detectors show a decrease in the neutron flux during thunderstorms. Recent research appears to support lightning generating 1013–1015 neutrons per discharge via photonuclear processes.
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Detectors relying on neutron absorption are generally more sensitive to low-energy thermal neutrons, and are orders of magnitude less sensitive to high-energy neutrons. Scintillation detectors, on the other hand, have trouble registering the impacts of low-energy neutrons.
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It is the most common oxide-based scintillator.Bismuth Germanate Scintillation Material. crystals.saint-gobain.com Bismuth germanium oxide is used in detectors in particle physics, aerospace physics, nuclear medicine, geology exploration, and other industries. Bismuth germanate arrays are used for gamma pulse spectroscopy.
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A scintillation counter detector, sensitive to energies of short-lived fission products, is mounted on a special dolly and moved over the outlets of the fuel channels, issuing an alert if increased radioactivity is detected in the steam-water flow.
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The Wilson chamber represented a primitive scintillation counter which could measure radioactivity. Measured over time, this sequential acquisition of radioactivity produced what was known as "circulation time". The longer the "circulation time", the weaker the heart. Blumgart's emphasis was twofold.
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See Effect of Cyprenorphine by Dr. Horace Dobbs. At the age of 20, Dobbs got married to his wife Wendy, and at 23, he graduated from London University with a BSc honours degree in Chemistry via part-time studies. From the Burroughs Wellcome laboratories, Horace Dobbs moved over to the Atomic Energy Authority (UKAEA), where he wrote two research publications, Quenching and Adsorption in Liquid scintillation counting, in 1962, and Dispensing solutions for liquid scintillation counting, published in the scientific and technical Aerospace reports, Volume 3, issue 17 in April 1965. While at UKAEA, Dobbs obtained his Ph.D. from Oxford University.
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Organic solutions such anthracene or stilbene, dissolved in benzene or toluene, fluoresce with ultraviolet or gamma ray irradiation. The decay times of this fluorescence are on the order of nanoseconds, since the duration of the light depends on the lifetime of the excited states of the fluorescent material, in this case anthracene or stilbene. Scintillation is defined a flash of light produced in a transparent material by the passage of a particle (an electron, an alpha particle, an ion, or a high-energy photon). Stilbene and derivatives are used in scintillation counters to detect such particles.
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Thus, any detector had to be capable of suppressing this background. Lead shielding to reject this background and provide angular collimation had proved unsuccessful since it generated its own background through interactions with cosmic rays. Frost was the first to suggest the use of an active scintillation shield around the X-ray/gamma-ray detector with the two connected in electronic anticoincidence to reject unwanted charged particle events and to provide the required angular collimation. K. J. Frost and E. D. Rothe, Detector for Low Energy Gamma-ray Astronomy Experiment, Proc. 8th Scintillation Counter Symposium, Washington, DC, 1–3 March 1962.
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Typical numbers are (when the incident particle is an electron): ≈40 photons/keV for , ~10 photons/keV for plastic scintillators, and ~8 photons/keV for bismuth germanate (). Scintillation detectors are generally assumed to be linear. This assumption is based on two requirements: (1) that the light output of the scintillator is proportional to the energy of the incident radiation; (2) that the electrical pulse produced by the photomultiplier tube is proportional to the emitted scintillation light. The linearity assumption is usually a good rough approximation, although deviations can occur (especially pronounced for particles heavier than the proton at low energies).
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For this reason, an instrument such as the dual phosphor scintillation probe, which will discriminate between alpha and beta, is used where routine checking will come across alpha and beta emitters simultaneously. This type of counter is known as "dual channel" and can discriminate between radiation types and give separate readouts for each. However, scintillation probes can be affected by high gamma background levels, which must therefore be checked by the skilled operator to allow the instrument to compensate. A common technique is to remove the counter from any proximity to alpha and beta emitters and allow a "background" count of gamma.
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The ORT has produced results on radio galaxies, quasars, supernovae and pulsars, One long-term program determined the angular structure of several hundred distant radio galaxies and quasars using the lunar occultation method. The application of this database to observational cosmology provided independent evidence against the steady state theory and supported the Big Bang model of the universe. The telescope is currently being used mainly to observe interplanetary scintillation, which may provide valuable information about the solar wind and magnetic storms that affect the near-Earth environment. Interplanetary scintillation observations provide a database to understand space weather changes and their predictability.
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Errors in procedure can also lead to errors in the results. If 1% of the benzene in a modern reference sample accidentally evaporates, scintillation counting will give a radiocarbon age that is too young by about 80 years.Bowman (1995), pp. 40–41.
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This is done by measuring an additional signal, which is much higher for electron recoils than nuclear recoils. CRESST detectors measure the scintillation light produced in a CaWO4 or ZnWO4 absorber crystal. EDELWEISS detectors measure the ionization produced in a semiconducting germanium crystal.
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The use of low-level gamma scintillation spectrometry in the measurements of activity in human beings. Radioactivity in Man. Ed. H. Meneely, C. C. Thomas, Springfield, IL: 16-30 May, H.A. and L.D. Marinelli. 1962. Sodium iodide systems: Optimum crystal dimensions and origin of background.
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Different levels of information can be used. A binary information can be based on the absence or presence of detected Cherenkov radiation. The amount or the direction of Cherenkov light can be used. In contrast to a scintillation counter the light production is instantaneous.
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Principle of operation of CFD A time to digital converter assigns timestamps. The time to digital converter needs fast rising edges with normed height. The plastic scintillation counter delivers fast rising edge with varying heights. Theoretically, the signal could be split into two parts.
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A scintillation detector or scintillation counter is obtained when a scintillator is coupled to an electronic light sensor such as a photomultiplier tube (PMT), photodiode, or silicon photomultiplier. PMTs absorb the light emitted by the scintillator and re-emit it in the form of electrons via the photoelectric effect. The subsequent multiplication of those electrons (sometimes called photo-electrons) results in an electrical pulse which can then be analyzed and yield meaningful information about the particle that originally struck the scintillator. Vacuum photodiodes are similar but do not amplify the signal while silicon photodiodes, on the other hand, detect incoming photons by the excitation of charge carriers directly in the silicon.
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The ArDM (Argon Dark Matter) Experiment is a particle physics experiment based on a liquid argon detector, aiming at measuring signals from WIMPs (Weakly Interacting Massive Particles), which probably constitute the Dark Matter in the universe. Elastic scattering of WIMPs from argon nuclei is measurable by observing free electrons from ionization and photons from scintillation, which are produced by the recoiling nucleus interacting with neighbouring atoms. The ionization and scintillation signals can be measured with dedicated readout techniques, which constitute a fundamental part of the detector. In order to get a high enough target mass the noble gas argon is used in the liquid phase as target material.
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Cline was part of a collaboration to detect cosmic energy depositions in the KeV range in 1993. The group proposed a liquid xenon detector that could detect energies low enough to provide evidence for WIMPs. The proposed detector would also be able to distinguish alpha particles from gamma rays using scintillation and charge signal techniques. Previous detectors were not able to differentiate between background radioactivity and electrical noise, but by the utilization of an active chamber with high charge detection efficiency and liquid xenon scintillation, Cline and others suggested and believed that this type of detector would be the most effective method of directly measuring WIMPs.
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However, for discrimination between alpha and beta particles or provision of particle energy information, scintillation counters or proportional counters should be used. Those instrument types are manufactured with much larger detector areas, which means that checking for surface contamination is quicker than with a Geiger counter.
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Apparatus with a scintillating crystal, photomultiplier, and data acquisition components. animation of radiation scintillation counter using a photomultiplier tube. When an ionizing particle passes into the scintillator material, atoms are excited along a track. For charged particles the track is the path of the particle itself.
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In the United Kingdom, the Health and Safety Executive, or HSE, has issued a user guidance note on selecting the correct radiation measurement instrument for the application concerned. This covers all radiation instrument technologies, and is a useful comparative guide to the use of scintillation detectors.
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Common scintillators include thallium-doped sodium iodide (NaI(Tl))—often simplified to sodium iodide (NaI) detectors—and bismuth germanate (BGO). Because photomultipliers are also sensitive to ambient light, scintillators are encased in light-tight coverings. Scintillation detectors can also be used to detect alpha- and beta- radiation.
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A Daly detector is a gas-phase ion detector that consists of a metal "doorknob", a scintillator (phosphor screen) and a photomultiplier.N. R. Daly, Scintillation Type Mass Spectrometer ion Detector . Rev. Sci. Instrum. 31(3), 264–267 (1960). It was named after its inventor Norman Richard Daly.
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Inorganic scintillators are usually crystals grown in high temperature furnaces, for example, alkali metal halides, often with a small amount of activator impurity. The most widely used is (thallium-doped sodium iodide); its scintillation light is blue. Other inorganic alkali halide crystals are: , , (pure), , , . Some non-alkali crystals include: , , , , , (), , .
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Scintillation properties of organic-inorganic methylamonium (MA) lead halide perovskites under proton irradiation were first reported by Shibuya et al. in 2002 and the first γ-ray pulse height spectrum, although still with poor energy resolution, was reported on () by van Eijk et al. in 2008 . Birowosuto at al.
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Review of Scientific Instruments, 27/110:858-859 Using this method, his investigations obtained the total content of natural potassium in the human bodyL.D. Marinelli (Supplement by H.A. May),1961. Use of low-level gamma-ray scintillation spectrometry in the measurements of activity in human beings. Radioactivity in Man.
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Part of a 12-inch (304 mm) 50-micrometre-resolution linear diode array XB8850-12 made by X-Scan Imaging Corporation; a horizontal, white scintillator strip overlays a linear silicon-integrated photodiode array mounted by chip- on-board surface-mount technology onto a green printed-circuit board A Linear diode array is used for digitizing x-ray images. The LDA system consists of an array of photodiode modules, The diodes are laminated with a scintillation screen to create x-ray sensitive diodes. The scintillation screen converts the photon energy emitted by the x-ray tube into visible light on the diodes. The diodes produce a voltage when the light energy is received.
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To detect acceleration of the injected electrons, a dipole magnet is installed after the vapor, bending their path. The larger the electron's energy, the smaller curvature of its path. A scintillation screen then detects accelerated electrons. The vapor source contains Rubidium (Rb) vapor which is ionized by a Ti:Sapphire laser.
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SPIE 4138, X-Ray Optics, Instruments, and Missions IV (2000) The proving flight, at least, used a high-pressure gas scintillation proportional counter with relatively low spatial resolution. This X-ray image of Cygnus X-1 was taken by HERO. Note the low spatial resolution of the image. NASA image.
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On July 21, 1964, the Crab Nebula supernova remnant was discovered to be a hard X-ray (15–60 keV) source by a scintillation counter flown on a balloon launched from Palestine, Texas, United States. This was likely the first balloon-based detection of X-rays from a discrete cosmic X-ray source.
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They find wide application in the field of radioactive contamination monitoring of personnel and the environment. Detectors are designed to have one or two scintillation materials, depending on the application. "Single phosphor" detectors are used for either alpha or beta, and "Dual phosphor" detectors are used to detect both. Glenn F Knoll.
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Dr. Bala Ram Joshi was a Nepalese scientist and professor of physics who made significant contributions to the fields of science and technology of Nepal. His Ph.D. thesis at The University of Glasgow, Studies of orbital electron capture by scintillation counter methods, thesis earned him the Thomson Prize at the University of Glasgow.
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The MiniBooNE detector employs pure mineral oil as its detection medium. Mineral oil is a natural scintillator, so charged particles without sufficient energy to produce Cherenkov light still produce scintillation light. Low- energy muons and protons, invisible in water, can be detected. Thus the use of natural environment as a measurement medium emerged.
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In 2018, the installation of an upgrade called AugerPrime has started adding scintillation and radio detectors to the Observatory. In 2010, an expanded version of AMANDA named IceCube was completed. IceCube measures Cherenkov light in a cubic kilometer of transparent ice. It is estimated to detect 275 million cosmic rays every day.
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Neutrino detectors are often built underground to isolate the detector from cosmic rays and other background radiation. Antineutrinos were first detected in the 1950s near a nuclear reactor. Reines and Cowan used two targets containing a solution of cadmium chloride in water. Two scintillation detectors were placed next to the cadmium targets.
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Temperature control was achieved using a binary gas–liquid system and hemispherical radiators mounted on the ends of the solar panels. The craft carried various scientific instruments including a magnetometer probe, television photographic equipment, a spectroreflexometer, radiation sensors (gas-discharge and scintillation counters), a spectrograph to study ozone absorption bands, and a micrometeoroid instrument.
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Scintillation detectors uses a photo luminescent source (such as ZnS) which interacts with radiation. When a radioactive particle decays and strikes the photo luminescent material a photon is released. This photon is multiplied in a photomultiplier tube which converts light into an electrical signal. This signal is then processed and converted into a channel.
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High operating speed is needed for good resolution of spectra. Precision of time measurement with a scintillation detector is proportional to . Short decay times are important for the measurement of time intervals and for the operation in fast coincidence circuits. High density and fast response time can allow detection of rare events in particle physics.
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Rubidium compounds have very few applications. Like caesium nitrate, it is used in infrared radiation producing pyrotechnic compositions as a colorant and an oxidizer, e.g. in decoys and illumination flares. It is also used as a raw material for preparation of other rubidium compounds and rubidium metal, for manufacture of catalysts and in scintillation counters.
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Instrumental setup of detectors around the probe. Energy spectrum of 149Gd with energy windows for start and stop. In the typical PAC spectrometer, a setup of four 90° and 180° planar arrayed detectors or six octahedral arrayed detectors are placed around the radioactive source sample. The detectors used are scintillation crystals of BaF2 or NaI.
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8th Scintillation Counter Symposium, Washington, DC, 1–3 March 1962. IRE Trans. Nucl. Sci., NS-9, No. 3, pp. 381-385 (1962) Plastic scintillators are often used to reject charged particles, while thicker CsI, bismuth germanate ("BGO"), or other active shielding materials are used to detect and veto gamma-ray events of non-cosmic origin.
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Tungsten(IV) sulfide is a high temperature lubricant and is a component of catalysts for hydrodesulfurization. MoS2 is more commonly used for such applications. Tungsten oxides are used in ceramic glazes and calcium/magnesium tungstates are used widely in fluorescent lighting. Crystal tungstates are used as scintillation detectors in nuclear physics and nuclear medicine.
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The X-ray telescope onboard OSO 4 consisted of a single thin NaI(Tl) scintillation crystal plus phototube assembly enclosed in a CsI(Tl) anti-coincidence shield. The energy resolution was 45% at 30 keV. The instrument operated from ~8 to 200 keV with 6 channel resolution. OSO 5 carried a CsI crystal scintillator.
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A gamma probe is a handheld device containing a scintillation counter, for intraoperative use following injection of a radionuclide, to locate sentinel lymph nodes by their radioactivity. It is used primarily for sentinel lymph node mapping and parathyroid surgery. Gamma probes are also used for RSL (radioactive seed localization), to locate small and non-palpable breast lesions.
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The cut displays a very sharp brilliance or fire if the diamond is cut to the correct depth allowing good scintillation. It is generally cut with a 1:1 length to width ratio with uncurved edges. This uncurved trilliant cut is usually used for accent gemstones, on either side of a main, larger stone of a ring.
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Cadmium tungstate (CdWO4 or CWO), the cadmium salt of tungstic acid, is a dense, chemically inert solid which is used as a scintillation crystal to detect gamma rays. It has density of 7.9 g/cm3 and melting point of 1325 °C. It is toxic if inhaled or swallowed. Its crystals are transparent, colorless, with slight yellow tint.
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Drawing of the Gamma space telescope satellite. The spaceframe and subsystems of the satellite were based on the Progress spacecraft. The Gamma-1 telescope was the main telescope. It consisted of 2 scintillation counters and a gas Cerenkov counter. With an effective area of around , it operated in the energy range of 50 MeV to 6 GeV.
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Photon emission can be detected by light sensitive apparatus such as a luminometer or modified optical microscopes. This allows observation of biological processes. Since light excitation is not needed for luciferase bioluminescence, there is minimal autofluorescence and therefore virtually background-free fluorescence. Therefore, as little as 0.02 pg can still be accurately measured using a standard scintillation counter.
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In the morning of September 29, a visiting medical physicist Note: person named only as "WF" in the IAEA report. used a scintillation counter to confirm the presence of radioactivity and persuaded the authorities to take immediate action. The city, state, and national governments were all aware of the incident by the end of the day.
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Charles Owen Dexter (1862-1943) was an American rhododendron hybridizer. Using the Chinese species Rhododendron fortunei, he produced hybrids characterized by dense foliage, large stature and flowers of superior size and color, many of which were also fragrant. Notable examples of his work include Scintillation, Betty Hume, Parker's Pink, GiGi, Mrs. W.R. Coe, Wheatley and Westbury.
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These experiments mostly use either cryogenic or noble liquid detector technologies. Cryogenic detectors operating at temperatures below 100 mK, detect the heat produced when a particle hits an atom in a crystal absorber such as germanium. Noble liquid detectors detect scintillation produced by a particle collision in liquid xenon or argon. Cryogenic detector experiments include: CDMS, CRESST, EDELWEISS, EURECA.
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In 1967, a radio signal was detected using the Interplanetary Scintillation Array of the Mullard Radio Astronomy Observatory in Cambridge, UK, by Jocelyn Bell Burnell. The signal had a -second period and 0.04-second pulsewidth. It originated at celestial coordinates right ascension, +21° declination. It was detected by individual observation of miles of graphical data traces.
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The modern electronic scintillation counter was invented in 1944 by Sir Samuel CurranOxford Dictionary of National Biography whilst he was working on the Manhattan Project at the University of California at Berkeley. There was a requirement to measure the radiation from small quantities of uranium and his innovation was to use one of the newly-available highly sensitive photomultiplier tubes made by the Radio Corporation of America to accurately count the flashes of light from a scintillator subjected to radiation. This built upon the work of earlier researchers such as Antoine Henri Becquerel, who discovered radioactivity whilst working on the phosphorescence of uranium salts in 1896. Previously scintillation events had to be laboriously detected by eye using a spinthariscope which was a simple microscope to observe light flashes in the scintillator.
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L. D. Marinelli British Journal of Radiology Suppl.(Nov 1956)7:38-43 In 1953 he improved and applied the "twin" scintillation low-level gamma-ray crystal spectrometry method to detect and locate elements that are naturally radioactive in the human bodyL. D. Marinelli, British Journal of Radiology Suppl.(Nov 1956)7:38-43 These methods were quickly copied in laboratories throughout the world and yielded insights into the human metabolisms of many elements and their compounds.Rossi, Harald H., Letter, April 15, 1975 In 1956, he developed the twin scintilltor method for dosimetry and spectrometry of fast neutrons and its application to the measurement of cosmic-ray neutron background(Patent # 2-795-703, June 11, 1957) Berlman, I.B. and L.D. Marinelli. June 25, 1956. Twin scintillation fast neutron detector.
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The WIMP Argon Programme (WARP) is an experiment at Laboratori Nazionali del Gran Sasso, Italy, for the research of cold dark matter. It aims to detect nuclear recoils in liquid argon induced by weakly interacting massive particles (WIMP) through scintillation light; the apparatus can also detect ionization so to exclude interactions of photons and electrons. The experiment is a recognized CERN experiment (RE15).
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The use of a scintillator in conjunction with a photomultiplier tube finds wide use in hand-held survey meters used for detecting and measuring radioactive contamination and monitoring nuclear material. Scintillators generate light in fluorescent tubes, to convert the ultra-violet of the discharge into visible light. Scintillation detectors are also used in the petroleum industry as detectors for Gamma Ray logs.
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Above very recent developments demonstrate that the organic-inorganic and all inorganic Pb-halide perovskites have various interesting scintillation properties. However, the recent 2-D perovskite single crystals will be more favorable as they may have much larger Stokes shift up to 200 nm in comparison with CsPbBr3 quantum dot scintillators and this is essential to prevent self reabsorption for scintillators.
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Graphic showing relationships between radioactivity and detected ionizing radiation. Hand-held large area alpha scintillation probe under calibration using a plate source in close proximity to the detector. Disintegrations per minute (dpm) and disintegrations per second (dps) are measures of the activity of the source of radioactivity. The SI unit of radioactivity, the becquerel (Bq), is equivalent to one disintegration per second.
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The primary experiment, the cosmic ray detector, could sense heavy cosmic rays with an atomic number over 30. The diameter acrylic-lined aluminum sphere was filled with a gaseous oxygen, nitrogen, and helium mixture. Heavy cosmic rays penetrated the sphere and excited the gas to produce scintillation light; the acrylic produced Cerenkov radiation. These ultraviolet emissions were detected with 16 photo- multipliers.
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The castle can be made from individual bricks; usually with interlocking chevron edges to prevent "shine paths" of direct radiation through the gaps. They can also be made from lead produced in bespoke shapes by machining or casting. Such an example would be the annular ring castle commonly used for shielding scintillation counters. A typical lead brick weighs about ten kilograms.
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For samples to be used in liquid scintillation counters, the carbon must be in liquid form; the sample is typically converted to benzene. For accelerator mass spectrometry, solid graphite targets are the most common, although gaseous can also be used.Trumbore (1996), p. 318. The quantity of material needed for testing depends on the sample type and the technology being used.
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Fluid properties such as density and viscosity can be inferred from the spectrum. Radiation-based Gauge: Radiation is passed from a source, through the fluid of interest, and into a scintillation detector, or counter. As the fluid density increases, the detected radiation "counts" will decrease. The source is typically the radioactive isotope cesium-137, with a half-life of about 30 years.
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Schematic showing incident high energy photon hitting a scintillating crystal, triggering the release of low-energy photons which are then converted into photoelectrons and multiplied in the photomultiplier A scintillation counter is an instrument for detecting and measuring ionizing radiation by using the excitation effect of incident radiation on a scintillating material, and detecting the resultant light pulses. It consists of a scintillator which generates photons in response to incident radiation, a sensitive photodetector (usually a photomultiplier tube (PMT), a charge-coupled device (CCD) camera, or a photodiode), which converts the light to an electrical signal and electronics to process this signal. Scintillation counters are widely used in radiation protection, assay of radioactive materials and physics research because they can be made inexpensively yet with good quantum efficiency, and can measure both the intensity and the energy of incident radiation.
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The Oriented Scintillation Spectrometer Experiment (OSSE) by the Naval Research Laboratory detected gamma rays entering the field of view of any of four detector modules, which could be pointed individually, and were effective in the 0.05 to 10 MeV range. Each detector had a central scintillation spectrometer crystal of NaI(Tl) 12 in (303 mm) in diameter, by 4 in (102 mm) thick, optically coupled at the rear to a 3 in (76.2 mm) thick CsI(Na) crystal of similar diameter, viewed by seven photomultiplier tubes, operated as a phoswich: i.e., particle and gamma-ray events from the rear produced slow-rise time (~1 μs) pulses, which could be electronically distinguished from pure NaI events from the front, which produced faster (~0.25 μs) pulses. Thus the CsI backing crystal acted as an active anticoincidence shield, vetoing events from the rear.
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Liquid scintillation counting is the measurement of radioactive activity of a sample material which uses the technique of mixing the active material with a liquid scintillator (e.g. Zinc sulfide) , and counting the resultant photon emissions. The purpose is to allow more efficient counting due to the intimate contact of the activity with the scintillator. It is generally used for alpha and beta particle detection.
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The goal of WALTA is to set up detectors at least 32 sites in the Seattle area, covering an area of 200 square kilometers. This area would be large enough to detect events above the GZK cutoff. The program hopes to fill in gaps in this area as the project matures. Each location has four scintillation detectors which emit light when hit by charged particles.
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Schilling 2002, p. 123 Throughout the month of May the radio scintillations became less noticeable until they ceased altogether. This implies that the radio source significantly expanded in the time that had passed since the burst was detected. Using the known distance to the source and the elapsed time before the scintillation ended, Frail calculated that the radio source had expanded at almost the speed of light.
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The near detector is at Fermilab and samples the unoscillated beam. The far detector is in northern Minnesota, and consists of about 500,000 cells, each 4 cm × 6 cm × 16 m, filled with liquid scintillator. Each cell contains a loop of bare fiber optic cable to collect the scintillation light, both ends of which lead to an avalanche photodiode for readout. The NOνA near detector.
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The ore was clearly detectable at a distance of a quarter-mile. However, it was known that equipment of much greater sensitivity would be needed for a practical airborne survey. In fact, scintillation detectors having both a much larger cross- section and much higher detection efficiency were already in airborne use in Canada and by the U.S. Geological Survey, although many of the details were secret.
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Their energy threshold was a few 1013eV. The AIROBICC array has been dismantled. The first detector type of HEGRA was the array of 1 m² scintillation counters which were used to measure the numbers and arrival times of secondary particles in air showers arriving at ground level. More than 250 of these counters were in operation, spread over a 180-by-180 m² area.
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The Disk-M telescope operated in the energy range 20 keV - 5 MeV. It consisted of Sodium iodide scintillation crystals, and had an angular resolution of 25 arcminutes. However, it stopped working shortly after the mission was launched. Finally, the Pulsar X-2 telescope had 30 arcminute resolution and a 10 deg x 10 deg field of view, and operated in the energy range 2-25 keV.
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The main scientific instrument is an array of 18 NaI(Tl)/CsI(na) slat-collimated "phoswich" scintillation detectors, collimated to 5.7°×1° overlapping fields of view.HXMT.cn, Configuration (Hard X-ray telescope design) c.2004 The main NaI detectors have an area of 286 cm2 each, and cover the 20–200 keV energy range. Data analysis is planned to be by a direct algebraic method, "direct demodulation",HXMT.
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In Manchester, he continued to work with alpha radiation. In conjunction with Hans Geiger, he developed zinc sulfide scintillation screens and ionisation chambers to count alphas. By dividing the total charge they produced by the number counted, Rutherford decided that the charge on the alpha was two. In late 1907, Ernest Rutherford and Thomas Royds allowed alphas to penetrate a very thin window into an evacuated tube.
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Television broadcasts featuring Nelson were notable for his multi-colored plaid sports jackets. He reportedly owned 335 of them at one time. During a broadcast, his jackets often clashed with the set and produced a scintillation effect in the broadcast image. But he figured that if fans could see rather than just hear broadcasts, he might as well give them something interesting to talk about.
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The animated image of the Moon's surface shows the effects of atmospheric turbulence on the view. Turbulence in Earth's atmosphere scatters the light from stars, making them appear brighter and fainter on a time-scale of milliseconds. The slowest components of these fluctuations are visible as twinkling (also called scintillation). Turbulence also causes small, sporadic motions of the star image, and produces rapid distortions in its structure.
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POPOP or 1,4-bis(5-phenyloxazol-2-yl) benzene is a scintillator. It is used as a wavelength shifter (also called a "secondary scintillator"), which means that it converts shorter wavelength light to longer wavelength light. Its output spectrum peaks at 410 nm, which is violet.Mechanism of Liquid Scintillation Counting, National Diagnostics, retrieved 24 Sept 2007 POPOP is used in both solid and liquid organic scintillators.
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Lithium molybdate is used as corrosion inhibitor in LiBr (Lithium bromide) absorption chiller for industrial central air conditioning. It is manufactured and shipped as either a colorless, transparent fluid or a white crystal powder. In either state it not classified as a hazardous material. Li2MoO4 crystals have been found applicable for cryogenic phonon-scintillation detectors, which are used to investigate some rare nuclear processes.
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A method called Scintillation proximity assay (SPA) has been recently developed, which eliminates this otherwise crucial step. It works through crystal lattice beads, which are coated with ligand coupling molecules and filled with cerium ions. These give off bursts of light when stimulated by an isotope, which can easily be measured. Ligands are radiolabeled using either 3H or 125I, and released into the assay.
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Solar Gamma-Rays in the 50 to 500 MeV Energy Range was an experiment operated by the University of Milan which was used to measure the flux of solar gamma ray emissions. It consisted of scintillators and photomultipliers, which measured the radiation. The Solar X-Ray Monitor was operated by the Utrecht University. It used a scintillation counter to detect hard x-rays emitted by the Sun.
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By the late 1980s, two different compounds containing technetium-99m were introduced: teboroxime and sestamibi. The utilization of Tc-99m would allow higher doses (up to ) due to the shorter physical (6 hours) half life of Tc-99m. This would result in more decay, more scintillation and more information for the nuclear cameras to measure and turn into better pictures for the clinician to interpret.
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Double Chooz was able to identify positronium formation in their detector, which delays positron annihilation and distorts the scintillation signal. A tagging algorithm was developed that could be used in neutrino detectors for improved background rejection, which was similarly done by Borexino for cosmogenic 11C background. An ortho-positronium lifetime of was measured, compatible with other dedicated setups. Limits on Lorentz violation parameters were also set.
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This imaging system in conjunction with a rotary table, can take a large number of images at different angles that can be reconstructed into a three-dimensional image (neutron tomography). When coupled with a thin scintillation screen and good optics these systems can produce high resolution images with similar exposure times to film imaging, though the imaging plane typically must be small given the number of pixels on the available CCD camera chips. Though these systems offer some significant advantages (the ability to perform real time imaging, simplicity and relative low cost for research application, potentially reasonably high resolution, prompt image viewing), significant disadvantages exist including dead pixels on the camera (which result from radiation exposure), gamma sensitivity of the scintillation screens (creating imaging artifacts that typically require median filtering to remove), limited field of view, and the limited lifetime of the cameras in the high radiation environments.
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The distance between this source and absorber was 22.5 meters (73.8 ft). The gamma rays traveled through a Mylar bag filled with helium to minimize scattering of the gamma rays. A scintillation counter was placed below the receiving 57Fe sample to detect the gamma rays that were not absorbed by the receiving sample. By vibrating the speaker cone the gamma ray source moved with varying speed, thus creating varying Doppler shifts.
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Small amounts of carbon-14 are not easily detected by typical Geiger–Müller (G-M) detectors; it is estimated that G-M detectors will not normally detect contamination of less than about 100,000 disintegrations per minute (0.05 µCi). Liquid scintillation counting is the preferred method."Radiation Safety Manual for Laboratory Users, Appendix B: The Characteristics of Common Radioisotopes" , Princeton University. The G-M counting efficiency is estimated to be 3%.
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Scintillation refers to the small flashes of light that are seen when the diamond, light source or the viewer is moved. A diamond that is cut and polished to produce a high level of these qualities is said to be high in light performance. The setting diamonds are placed in also affect the performance of light through a diamond. The three most commonly used settings are: Prong, Bezel, and Channel.
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The technology was improved, and by 1951 the four ionization chambers were replaced by twenty scintillation counters, each using five gallons of a liquid scintillator. The flashes from of burning scintillator were remarkably brilliant in the early morning times when the tests were usually performed. RaLa tests continued until 1962, after which they were replaced by more advanced methods. Currently several other methods are used for hydrodynamic testing.
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Scintillation in radio waves due to the ionosphere was observed as early as 1951 by Antony Hewish, and he then reported irregularities in radiation received during an observation of a bright radio source in Taurus in 1954.Hewish (1955), p. 238. Hewish considered various possibilities, and suggested that irregularities in the solar corona would cause scattering by refraction and could produce the irregularities he observed.Hewish (1955), pp. 242–244.
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Antineutrinos were first detected near the Savannah River nuclear reactor by the Cowan–Reines neutrino experiment in 1956. Frederick Reines and Clyde Cowan used two targets containing a solution of cadmium chloride in water. Two scintillation detectors were placed next to the water targets. Antineutrinos with an energy above the threshold of 1.8 MeV caused charged current "inverse beta-decay" interactions with the protons in the water, producing positrons and neutrons.
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Since the neutron is not charged it does not interact via the Coulomb force and therefore does not ionize the scintillation material. It must first transfer some or all of its energy via the strong force to a charged atomic nucleus. The positively charged nucleus then produces ionization. Fast neutrons (generally >0.5 MeV ) primarily rely on the recoil proton in (n,p) reactions; materials rich in hydrogen, e.g.
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After its founding in 1983, Positron debuted a new time-of-flight tomograph called the POSICAM. Posicam used barium fluoride for the scintillation detector and was primarily used by researchers interested in cardiac imaging. In 1985, the FDA approved the POSICAM system for marketing and the following year, Positron began commercial operations. The FDA later gave approval to Positron to begin marketing its HZ PET imaging system in 1991.
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Neutron detection is the effective detection of neutrons entering a well- positioned detector. There are two key aspects to effective neutron detection: hardware and software. Detection hardware refers to the kind of neutron detector used (the most common today is the scintillation detector) and to the electronics used in the detection setup. Further, the hardware setup also defines key experimental parameters, such as source-detector distance, solid angle and detector shielding.
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This particular characteristic is generally accepted in most systems interested in light behavior of a diamond. Sparkle is measured as variation of grey scale values among pixels within the perimeter of a diamond. ImaGem uses sparkle to identify the dynamic behavior (scintillation) when a diamond or light is moved. Intensity (contrast) is a new concept introduced by ImaGem to capture the pattern of dark and bright areas in a diamond.
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Scintillation is a fluctuation in the amplitude of a target on a radar display. It is closely related to target glint, or wander, an apparent displacement of the target from its mean position. This effect can be caused by a shift of the effective reflection point on the target, but has other causes as well. The fluctuations can be slow (scan-to-scan) or rapid (pulse- to-pulse).
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The first stage of the DEAP project, DEAP-1, was designed in order to characterize several properties of liquid argon, demonstrate pulse-shape discrimination, and refine engineering. This detector was too small to perform dark matter searches. DEAP-1 used 7 kg of liquid argon as a target for WIMP interactions. Two photomultiplier tubes (PMTs) were used to detect the scintillation light produced by a particle interacting with the liquid argon.
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Caesium nitrate prisms are used in infrared spectroscopy, in x-ray phosphors, and in scintillation counters.. It is also used in making optical glasses and lenses. As with other alkali metal nitrates, caesium nitrate decomposes on gentle heating to give caesium nitrite: :2CsNO3 → 2CsNO2 \+ O2 Caesium also forms two unusual acid nitrates, which can be described as CsNO3·HNO3 and CsNO3·2HNO3 (melting points 100 °C and 36–38 °C respectively).
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It is often reported in multiples of the so-called TEC unit, defined as TECU=1016el/m2. TEC is significant in determining the scintillation and group and phase delays of a radio wave through a medium. Ionospheric TEC is characterized by observing carrier phase delays of received radio signals transmitted from satellites located above the ionosphere, often using Global Positioning System satellites. TEC is strongly affected by solar activity.
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These preparations routes are called the halide flux method and the sulfite precipitation method. The scintillation properties of Gd2O2S: Pr, Ce, F complexes demonstrate that this scintillator is promising for imaging applications. There are two main disadvantages to this scintillator; one being the hexagonal crystal structure, which emits only optical translucency and low external light collection at the photodiode. The other disadvantage is the high X-ray damage to the sample.
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The Plexiglas layer between regions I and II was clear, to allow scintillation light from region I to be observed by the PMTs in region II. The inner surface of the region II container was painted black to avoid reflections, which would degrade position measurements. The outer surface of the region II container and the inner surface of the region III container were painted white to maximize the veto signals.
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In December 2002 he created the Institute for Scintillation Materials within the structure of the NAS of Ukraine and was its director from 2002 to 2011. In 2006 became the Member (Academician) of National Academy of Sciences of Ukraine. Since 2007 he has been the Head of Department of Crystal Physics at Kharkiv National University. From 2010 till 2015 was a member of Presidium of National Academy of Sciences of Ukraine.
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An example of lung scintigraphy examination A gamma camera (γ-camera), also called a scintillation camera or Anger camera, is a device used to image gamma radiation emitting radioisotopes, a technique known as scintigraphy. The applications of scintigraphy include early drug development and nuclear medical imaging to view and analyse images of the human body or the distribution of medically injected, inhaled, or ingested radionuclides emitting gamma rays.
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Geister, R. L., Bandla, M. D., Sutula, C. L., Multiplex enzyme-linked immunosorbent assay for detecting multiple analytes, U.S. Patent Appl. Number: 20040231776 4\. Stiso, S. N., Sutula, C. L., Method, composition and device for determining the specific gravity or osmolality of a liquid, U.S. Patent Number: 4,108,727 5\. Sena, E. A., Tolbert, B. M., Sutula, C. L., Liquid scintillation, counting and compositions, U.S. Patent Number: 3,928,227 6\.
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In 1948, Kallmann's knowledge about photomultiplier scintillation counters brought him to the United States as a research fellow for the U.S. Army Signal Corps Laboratory in Belmar, New Jersey. The book, Pions to Quarks: Particle Physics in the 1950s describes Kallmann's contribution to particle physics. In 1948 he emigrated to the US and established a research lab at New York University. He died in Munich at the age of 82.
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The scientific instruments consisted of an ion chamber and Geiger-Müller tube to measure total radiation flux, a proportional radiation counter telescope to measure high energy radiation, a scintillation counter to monitor low-energy radiation, a VLF receiver for natural radio waves, a transponder to study electron density, and part of the flux-gate and search coil magnetometers mounted on the instrument platform. The micrometeorite detector and sun scanner were mounted on the sphere. The difference between the payload of Pioneer P-30 and the earlier Pioneer P-3 was the replacement of the TV facsimile system on P-3 with a scintillation spectrometer to study the Earth's (and possible lunar) radiation belts, mounted on the instrument platform, and a plasma probe mounted on the sphere to measure energy and momentum distribution of protons above a few kilovolts to study the radiation effect of solar flares. The total mass of the science package including electronics and power supply was roughly .
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The scientific instruments consisted of an ion chamber and Geiger-Müller tube to measure total radiation flux, a proportional radiation counter telescope to measure high energy radiation, a scintillation counter to monitor low-energy radiation, a scintillation spectrometer to study the Earth's (and possible lunar) radiation belts, a VLF receiver for natural radio waves, a transponder to study electron density, and part of the flux-gate and search coil magnetometers mounted on the instrument platform. A plasma probe was mounted on the sphere to measure energy and momentum distribution of protons above a few kilovolts to study the radiation effect of solar flares. The micrometeorite detector and sun scanner were mounted on the sphere as well. The only difference between Pioneer P-31 and the earlier Pioneer P-30 was the addition of a solid state detector sensitive to low energy protons on the satellite and an STL-designed rubidium frequency standard experiment placed on a pod attached to the booster.
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Figure 1: Sodium iodide gamma spectrum of caesium-137 () Figure 2: Sodium iodide gamma spectrum of cobalt-60 () Thallium-doped sodium iodide (NaI(Tl)) has two principal advantages: # It can be produced in large crystals, yielding good efficiency, and # it produces intense bursts of light compared to other spectroscopic scintillators. NaI(Tl) is also convenient to use, making it popular for field applications such as the identification of unknown materials for law enforcement purposes. Electron hole recombination will emit light that can re-excite pure scintillation crystals; however, the thallium dopant in NaI(Tl) provides energy states within the band gap between the conduction and valence bands. Following excitation in doped scintillation crystals, some electrons in the conduction band will migrate to the activator states; the downward transitions from the activator states will not re-excite the doped crystal, so the crystal is transparent to this radiation. An example of a NaI spectrum is the gamma spectrum of the caesium isotope —see Figure 1.
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The efficiency of this process is 4–50%, depending on the scintillation cocktail used. The measurements are typically expressed in counts per minute (CPM) or disintegrations per minute (DPM). Alternatively, a solid-state, tritium-specific phosphor screen can be used together with a phosphorimager to measure and simultaneously image the radiotracer. Measurements/images are digital in nature and can be expressed in intensity or densitometry units within a region of interest (ROI).
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Charles James "Chuck" Hailey is an experimental astrophysicist and Pupin Professor of Physics at Columbia University. He earned his BA in Physics from Cornell University in 1977 and his PhD from Columbia in 1983, with a thesis entitled "The Development of an Imaging Gas Scintillation Proportional Counter for Use in X-ray Astronomy." He received tenure from Columbia University in 1995. Hailey's research focuses on high energy astrophysics and experimental particle physics.
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In the gem trade, the term light performance is used to describe how well a polished diamond will return light to the viewer. There are three light properties which are described in relation to light performance: brilliance, fire, and scintillation. Brilliance refers to the white light reflections from the external and internal facet surfaces. Fire refers to the spectral colors which are produced as a result of the diamond dispersing the white light.
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Alpha-particle spectroscopy is a method of measuring the radionuclides based on emission of α particles. They can be measured by a variety of detectors, including liquid scintillation counters, gas ionization detectors, and ion-implanted silicon semiconductor detectors. Typical alpha-particle spectrometers have low backgrounds and measure particles ranging from 3 to 10 MeV. Radionuclides that decay through α emission tend to eject α particles with discrete, characteristic energies between 4 and 6 MeV.
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A method that does not require separation is the scintillation proximity assay that relies on the fact that β-rays from 3H travel extremely short distances. The receptors are bound to beads coated with a polyhydroxy scintillator. Only the bound ligands to be detected. Today, the fluorescence method is preferred to radioactive materials due to a much lower cost, lower hazard, and the possibility of multiplexing the reactions in a high-throughput manner.
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Manchester (1977), pp. 1–2. Soon after observations were under way, Hewish's student Jocelyn Bell turned this assumption on its head, when she noticed a signal which was soon recognized as emanating from a new class of object, the pulsar. Thus "it was an investigation of interplanetary scintillation that led to the discovery of pulsars, even though the discovery was a by-product rather than the purpose of the investigation."Lyne (1990). p. 4.
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Scintillation occurs as a result of variations in the refractive index of the medium through which waves are traveling. The solar wind is a plasma, composed primarily of electrons and lone protons, and the variations in the index of refraction are caused by variations in the density of the plasma.Jokipii (1973), pp. 11–12. Different indices of refraction result in phase changes between waves traveling through different locations, which results in interference.
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Resistance and good behavior under high-temperature, high-vibration environments is especially important for applications such as oil exploration (wireline logging, measurement while drilling). For most scintillators, light output and scintillation decay time depends on the temperature. This dependence can largely be ignored for room-temperature applications since it is usually weak. The dependence on the temperature is also weaker for organic scintillators than it is for inorganic crystals, such as NaI-Tl or BGO.
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LYSO, BGO) are typically preferred for this type of applications. Scintillation in inorganic crystals is typically slower than in organic ones, ranging typically from 1.48 ns for to 9000 ns for . Exceptions are } (~5 ns), fast (0.7 ns; the slow component is at 630 ns), as well as the newer products (, 28 ns; , 16 ns; , 41 ns). For the imaging application, one of the advantage of inorganic crystals is very high light yield.
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The excitons are loosely bound electron-hole pairs which wander through the crystal lattice until they are captured as a whole by impurity centers. The latter then rapidly de-excite by emitting scintillation light (fast component). The activator impurities are typically chosen so that the emitted light is in the visible range or near-UV where photomultipliers are effective. The holes associated with electrons in the conduction band are independent from the latter.
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The latter then rapidly de-excite by emitting scintillation light (fast component). In the case of inorganic scintillators, the activator impurities are typically chosen so that the emitted light is in the visible range or near-UV, where photomultipliers are effective. The holes associated with electrons in the conduction band are independent from the latter. Those holes and electrons are captured successively by impurity centers exciting certain metastable states not accessible to the excitons.
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This creates a more uniform electric field in order to preserve the shape of the original track during amplification. The avalanche of electrons also creates a great deal of scintillation light, which passes through the wire mesh. Some of this light is collected by a CCD camera located outside the main detector volume. This results in a two dimensional image of the ionization signal of the track as it appeared on the amplification plane.
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He worked on the giant scintillation counters at Fermilab, and directed searches for charm quark s there with photon and neutron beams, and at SLAC using colliding electron-positron beams. Between 1953 and 2003, he was the author of over 115 papers. He retired in 1986. In retirement, Wattenberg became involved with the American Physical Society's Forum of the History of Physics, as a councillor, secretary-treasurer, and editor of the newsletter.
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There are two detector configurations utilised, they are the planar detector, used for PGNAA and the well detector, used for DGNAA. The planar detector has a flat, large collection surface area and can be placed close to the sample. The well detector ‘surrounds’ the sample with a large collection surface area. Scintillation-type detectors use a radiation- sensitive crystal, most commonly thallium-doped sodium iodide (NaI(Tl)), which emits light when struck by gamma photons.
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The extreme measurements included one with a maximum age of under 4,400 years, and another with a minimum age of over 4,500 years.Taylor, Radiocarbon Dating, pp. 125−126. It is also possible for laboratories to have systematic errors, caused by weaknesses in their methodologies. For example, if 1% of the benzene in a modern reference sample is allowed to evaporate, scintillation counting will give a radiocarbon age that is too young by about 80 years.
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Diffractometers can be operated both in transmission and reflection, but reflection is more common. The powder sample is loaded in a small disc-like container and its surface carefully flattened. The disc is put on one axis of the diffractometer and tilted by an angle θ while a detector (scintillation counter) rotates around it on an arm at twice this angle. This configuration is known under the name Bragg–Brentano θ-2θ.
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Beta particles are electrons or positrons and can travel farther than alpha particles in air. The gamma rays emitted from radium 226, accounting for 4% of the radiation, are harmful to humans with sufficient exposure. Gamma rays are highly penetrating and some can pass through metals, so Geiger counters or a scintillation probe are used to measure gamma ray exposures when monitoring for NORM. Alpha and beta particles are harmful once inside the body.
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Gamma rays emitted from the radioactive sample interact with the crystal, are absorbed, and light is emitted. A detector, such as a photomultiplier tube converts the visible light to an electrical signal. Depending on the half-life and concentration of the sample, measurement times may vary from 0.02 minutes to several hours. If the photon has too low of an energy level it will be absorbed into the scintillation crystal and never be detected.
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An early example of such a system, first proposed by Kenneth John Frost in 1962, is shown in the figure. It has an active CsI(Tl) scintillation shield around the X-ray/gamma-ray detector, also of CsI(Tl), with the two connected in electronic anticoincidence to reject unwanted charged particle events and to provide the required angular collimation. K. J. Frost and E. D. Rothe, Detector for Low Energy Gamma-ray Astronomy Experiment, Proc.
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From April, 2010 he is the Scientific Director of Institute for Scintillation Materials NAS of Ukraine. From April till July, 2010 he was the Chairman of State Committee Scientific and Technical Progress and Innovations of Ukraine. B. Grinyov was a member of Committee of Ukraine State Prizes for Science and Technology in 2010-2015. From 1997 to 2003 and since 2010, he represents Ukraine in the Joint Institute for Nuclear Research (JINR) in Dubna, Russia.
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This is a major limitation for heart muscle imaging systems; the thickest normal heart muscle in the left ventricle is about 1.2 cm and most of the left ventricle muscle is about 0.8 cm, always moving and much of it beyond 5 cm from the collimator face. To help compensate, better imaging systems limit scintillation counting to a portion of the heart contraction cycle, called gating, however this further limits system sensitivity.
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Miller, C.E., and L.D. Marinelli. 1956. The gamma- ray activity of contemporary man. Science, 124 (3212) (July 20): 122-123 Berlman, I.B. and Marinelli L.D. June 25, 1956. “Twin” scintillation fast neutron detector. Rev. Sci. Instr. 27(10): 858-859 Gustafson, P.F., L. D. Marinelli, and E. A. Hathaway. 1957. A case of accidental puncture contaminated with thorium-227: Studies on elimination and residual body activity. Radiology 68(3) (March): 358-365. Marinelli, L.D. Nov. 1958.
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23 Vulpeculae is the second brightest star in the constellation. In 1967, the first pulsar, PSR B1919+21, was discovered in Vulpecula by Jocelyn Bell, supervised by Antony Hewish, in Cambridge. While they were searching for scintillation of radio signals of quasars, they observed pulses which repeated with a period of 1.3373 seconds. Terrestrial origin of the signal was ruled out because the time it took the object to reappear was a sidereal day instead of a solar day.
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Tunka-Grande consists of 19 scintillation stations with an area of 10 m² each from the closed KASCADE-Grande array. These stations measure the particles of the air showers at ground, in particular electrons and muons. All stations are installed in the area of Tunka-133. They are operated simultaneously with the radio antennas of Tunka-Rex, since the combination of both measurement techniques is expected to enhance the accuracy for the composition of the cosmic rays.
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"NASA Aerospace Science and Technology Dictionary", NASA.gov. As one of the three principal factors governing astronomical seeing (the others being light pollution and cloud cover), atmospheric twinkling is defined as variations in illuminance only. In simple terms, twinkling of stars is caused by the passing of light through different layers of a turbulent atmosphere. Most scintillation effects are caused by anomalous atmospheric refraction caused by small-scale fluctuations in air density usually related to temperature gradients.
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Radiation Detection and Measurement, third edition 2000. John Wiley and sons, A scintillator such as zinc sulphide is used for alpha particle detection, whilst plastic scintillators are used for beta detection. The resultant scintillation energies can be discriminated so that alpha and beta counts can be measured separately with the same detector, This technique is used in both hand-held and fixed monitoring equipment, and such instruments are relatively inexpensive compared with the gas proportional detector.
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Liquid argon is advantageous as a sensitive medium for several reasons.Acciarri et al. 2015. The fact that argon is a noble element and therefore has a vanishing electronegativity means that electrons produced by ionizing radiation will not be absorbed as they drift toward the detector readout. Argon also scintillates when an energetic charged particle passes by, releasing a number of scintillation photons that is proportional to the energy deposited in the argon by the passing particle.
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For example, in a scintillation detector, incident radiation excites a fluorescent material that de-excites by emitting photons of light. The light is focused onto the photocathode of a photomultiplier tube that triggers an electron avalanche. The electron shower produces an electrical pulse that activates a meter read by the operator. Not surprisingly, the quantitative relationship between the amount of radiation actually emitted and the reading on the meter is a complex function of many factors.
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Using 14 beams, it can map the northern sky in one day. The observatory's staff use sheep to keep grass away from the antennas because a lawn mower cannot fit in the spaces. Antony Hewish designed the IPS Array to measure the high-frequency fluctuations of radio sources, originally for monitoring interplanetary scintillation. Hewish received a Nobel prize after the high time-resolution of the array allowed the detection of pulsars by Jocelyn Bell in 1967.
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At the focus of two of the telescopes is a gas imaging spectrometer (GIS), while a solid- state imaging spectrometer (SIS) is at the focus of the other two. The GIS is a gas-imaging scintillation proportional counter and is based on the GSPC that flew on the second Japanese X-ray astronomy mission TENMA. The two identical charge-coupled device (CCD) cameras were provided for the two SISs by a hardware team from MIT, Osaka University and ISAS.
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Natural gamma ray tools are designed to measure gamma radiation in the Earth caused by the disintegration of naturally occurring potassium, uranium, and thorium. Unlike nuclear tools, these natural gamma ray tools emit no radiation. The tools have a radiation sensor, which is usually a scintillation crystal that emits a light pulse proportional to the strength of the gamma ray striking it. This light pulse is then converted to a current pulse by means of a photomultiplier tube (PMT).
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Homemade Lucas cell A Lucas cell is a type of scintillation counter. It is used to acquire a gas sample, filter out the radioactive particulates through a special filter and then count the radioactive decay. The inside of the gas chamber is coated with ZnS(Ag) - a chemical that emits light when struck by alpha particles. A photomultiplier tube at the top of the chamber counts the photons and sends the count to a data logger.
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To create benzene for liquid scintillation counters, the sequence begins with combustion to convert the carbon in the sample to . This is then converted to lithium carbide, and then to acetylene, and finally to benzene. Targets for accelerator mass spectrometry are created from by catalysing the reduction of the gas in the presence of hydrogen. This results in a coating of filamentous carbon (usually referred to as graphite) on the powdered catalyst--typically cobalt or iron.
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Tritium is produced by neutron irradiation of 6Li :6Li + n → 4He + 3H Tritium has a half-life 4,500±8 days (approximately 12.32 years), and it decays by beta decay. The electrons produced have an average energy of 5.7 keV. Because the emitted electrons have relatively low energy, the detection efficiency by scintillation counting is rather low. However, hydrogen atoms are present in all organic compounds, so tritium is frequently used as a tracer in biochemical studies.
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The total number of pulses (but not their amplitude) is counted, giving an integer number of photons detected per measurement period. The counting efficiency is determined by the quantum efficiency and any electronic losses that are present in the system. Many photodetectors can be configured to detect individual photons, each with relative advantages and disadvantages. Common types include photomultipliers, geiger counters, single-photon avalanche diodes, superconducting nanowire single-photon detectors, transition edge sensors, and scintillation counters.
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A Small Article Monitor or SAM is a monitoring device designed to screen small items of up to 50 pounds weight for radioactive contamination. It uses six plastic scintillation detectors, one each on the top, bottom, back, left and right sides of the chamber, plus one in the door. Operation of the instrument is controlled from an integral terminal. The instrument performs a self-test and acquires a new Background count each time it is powered up.
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She obtained her MD degree from the University Innsbruck, Austria, 1968. She published her first scientific paper in 1971 titled "Segmental, Sequential and Quantitative Pulmonary Investigations Using the Scintillation Camera" in the Journal of Nuclear Biology and Medicine. During her career, she published over 254 scientific manuscripts with more than 4713 citations, written many book chapters, and organised symposiums. She is also mentioned in the book "History of Nuclear Medicine in Europe," which was published in 2003.
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The use of radioactive tracer elements in ion uptake assays allows the calculation of km, Ki and Vmax and determines the initial change in the ion content of the cells. 28Mg decays by the emission of a high-energy beta or gamma particle, which can be measured using a scintillation counter. However, the radioactive half-life of 28Mg, the most stable of the radioactive magnesium isotopes, is only 21 hours. This severely restricts the experiments involving the nuclide.
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Blue diffuse light is coming out of the tube. Liquid xenon is used in calorimeters to measure gamma rays, and as a detector of hypothetical weakly interacting massive particles, or WIMPs. When a WIMP collides with a xenon nucleus, theory predicts it will impart enough energy to cause ionization and scintillation. Liquid xenon is useful for these experiments because its density makes dark matter interaction more likely and it permits a quiet detector through self-shielding.
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Visible light time domain studies include HAT-South, the Large Synoptic Survey Telescope, PanSTARRS, SkyMapper, the Wide Angle Search for Planets and the Catalina Real-time Transient Survey. In radio astronomy the LOFAR is looking for radio transients. Radio time domain studies have long included pulsars and scintillation. Cherenkov Telescope Array, eROSITA, AGILE, Fermi, HAWC, INTEGRAL, MAXI, Swift Gamma-Ray Burst Mission and Space Variable Objects Monitor will look for transients in X-ray and gamma rays.
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The use of the magnetic field of the objective lens of the microscope has been incorporated in another commercial patent., (December 6, 2005) Particle-optical device and detection means. Inventors: Scholtz Jacob Johannes, Knowles W. Ralph, Thiel Bradley Lamar, Van Veen Gerardus, Schroemges Rene Peter Marie LEO company (now Carl Zeiss SMT) has used the scintillation mode and the ionization (needle) mode of the GDD on its environmental SEMs at low and also extended pressure range.
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The colors triggered by certain sounds, and any other synesthetic visual experiences, are referred to as photisms. According to Richard Cytowic, chromesthesia is "something like fireworks": voice, music, and assorted environmental sounds such as clattering dishes or dog barks trigger color and firework shapes that arise, move around, and then fade when the sound ends. Sound often changes the perceived hue, brightness, scintillation, and directional movement. Some individuals see music on a "screen" in front of their faces.
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Benjamin Bederson, "Fritz Reiche and the Emergency Committee in Aid of Displaced Foreign Scholars", Physics in perspective 7 p.453-472, 2005, p.459 Kallmann built the world's first organic scintillator in Berlin. Thermo Electron corporation (now Thermo Fisher Scientific) credited Kallmann and Broser with pioneering modern day scintillation counting by combining a scintillating material with a photomultiplier, as a means of improving light detection and reducing the eye fatigue apparently common to earlier, cruder methods of detection.
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An illustration of Telescope Array. Three fluorescence telescopes observe the ultraviolet light given off by an air shower, while an array of surface detectors register the particles as they strike the ground. The Telescope Array observatory is a hybrid detector system consisting of both an array of 507 scintillation surface detectors (SD) which measure the distribution of charged particles at the Earth's surface, and three fluorescence stations which observe the night sky above the SD array.T. AbuZayyad et al.
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The ionosphere bends radio waves in the same manner that water in a swimming pool bends visible light. When the medium through which such waves travel is disturbed, the light image or radio information is distorted and can become unrecognizable. The degree of distortion (scintillation) of a radio wave by the ionosphere depends on the signal frequency. Radio signals in the VHF band (30 to 300 MHz) can be distorted beyond recognition by a disturbed ionosphere.
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The frequency of geomagnetic storms increases and decreases with the sunspot cycle. CME driven storms are more common during the solar maximum of the solar cycle, while CIR-driven storms are more common during the solar minimum. Several space weather phenomena are associated with geomagnetic storms. These include Solar Energetic Particle (SEP) events, geomagnetically induced currents (GIC), ionospheric disturbances that cause radio and radar scintillation, disruption of compass navigation and auroral displays at much lower latitudes than normal.
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Laboratory equipment for determination of γ-radiation spectrum with a scintillation counter. The output from the scintillation counter goes to a Multichannel Analyser which processes and formats the data. Atomic nuclei have an energy-level structure somewhat analogous to the energy levels of atoms, so that they may emit (or absorb) photons of particular energies, much as atoms do, but at energies that are thousands to millions of times higher than those typically studied in optical spectroscopy. (Note that the short-wavelength high-energy end, of the atomic spectroscopy energy range (few eV to few hundred keV), generally termed X rays, overlaps somewhat with the low end of the nuclear gamma-ray range (~10 MeV to ~10 keV) so that the terminology used to distinguish X rays from gamma rays can be arbitrary or ambiguous in the overlap region.) As with atoms, the particular energy levels of nuclei are characteristic of each species, so that the photon energies of the gamma rays emitted, which correspond to the energy differences of the nuclei, can be used to identify particular elements and isotopes.
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H.V. Ellsworth of the GSC built a lighter weight, more practical unit in 1934. Subsequent models were the principal instruments used for uranium prospecting for many years, until geiger counters were replaced by scintillation counters. The use of airborne detectors to prospect for radioactive minerals was first proposed by G.C. Ridland, a geophysicist working at Port Radium in 1943. In 1947, the earliest recorded trial of airborne radiation detectors (ionization chambers and Geiger counters) was conducted by Eldorado Mining and Refining Limited.
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This interference, known as "quenching", can be overcome through data correction or through careful sample preparation. High-energy beta emitters, such as phosphorus-32, can also be counted in a scintillation counter without the cocktail, instead using an aqueous solution. This technique, known as Cherenkov counting, relies on the Cherenkov radiation being detected directly by the photomultiplier tubes. Cherenkov counting in this experimental context is normally used for quick, rough measurements, since the geometry of the sample can create variations in the output.
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15 With modification, these categories can be useful in understanding the grading of all gemstones. The four criteria carry different weights depending upon whether they are applied to colored gemstones or to colorless diamonds. In diamonds, the cut is the primary determinant of value, followed by clarity and color. The ideal cut diamond will sparkle, to break down light into its constituent rainbow colors (dispersion), chop it up into bright little pieces (scintillation), and deliver it to the eye (brilliance).
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The range of photoemissive devices using caesium include optical character recognition devices, photomultiplier tubes, and video camera tubes. Nevertheless, germanium, rubidium, selenium, silicon, tellurium, and several other elements can be substituted for caesium in photosensitive materials. Caesium iodide (CsI), bromide (CsBr) and caesium fluoride (CsF) crystals are employed for scintillators in scintillation counters widely used in mineral exploration and particle physics research to detect gamma and X-ray radiation. Being a heavy element, caesium provides good stopping power with better detection.
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Common detector materials include sodium iodide (NaI) scintillation counters and high-purity germanium detectors. To accurately determine the energy of the gamma ray, it is advantageous if the photoelectric effect occurs, as it absorbs all of the energy of the incident ray. Absorbing all the energy is also possible when a series of these interaction mechanisms take place within the detector volume. With Compton interaction or pair production, a portion of the energy may escape from the detector volume, without being absorbed.
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Jablonski diagram shows the energy levels in a fluorescing atom in a phosphor. An electron in the phosphor absorbs a high-energy photon from the applied radiation, exciting it to a higher energy level. After losing some energy in non-radiative transitions, it eventually transitions back to its ground state energy level by fluorescence, emitting a photon of lower energy in the visible light region. The scintillation process in inorganic materials is due to the electronic band structure found in the crystals.
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If a knife edge is not used, the system is generally referred to as a shadowgraph system, which measures the second derivative of density. Diagram of classical schlieren imaging using a parabolic concave mirror If the fluid flow is uniform, the image will be steady, but any turbulence will cause scintillation, the shimmering effect that can be seen over heated surfaces on a hot day. To visualise instantaneous density profiles, a short-duration flash (rather than continuous illumination) may be used.
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These are pollutants which emit radioactive materials, such as alpha and beta particles, posing danger to human health and the environment. Particle counters and Scintillation counters are most commonly used for these measurements. Bioassays and immunoassays are utilized for toxicity evaluations of chemical effects on various organisms. Polymerase Chain Reaction PCR is able to identify species of bacteria and other organisms through specific DNA and RNA gene isolation and amplification and is showing promise as a valuable technique for identifying environmental microbial contamination.
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Plant radiation detectors that are operating in a high ambient gamma background are sometimes shielded to prevent the background swamping the detector. Such a detector may be looking for alpha and beta particles, and gamma radiation will affect this. Laboratory or health physics detectors, even if remote from nuclear operations, may require shielding if very low levels of radiation are to be detected. This is the case with, for instance, a scintillation counter measuring low levels of contamination on a swab or sample.
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Gamma rays are absorbed high in the Earth's atmosphere so most gamma-ray astronomy is conducted with satellites. Gamma-ray telescopes use scintillation counters, spark chambers and more recently, solid-state detectors. The angular resolution of these devices is typically very poor. There were balloon-borne experiments in the early 1960s, but gamma-ray astronomy really began with the launch of the OSO 3 satellite in 1967; the first dedicated gamma-ray satellites were SAS B (1972) and Cos B (1975).
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Target cell lysis is determined by measuring the amount of radiolabel released into the cell culture medium by means of a gamma counter or scintillation counter. A variety of non-radioactive methods are now in widespread use. Fluorescence-based methods include such things as direct labelling with a fluorescent dye like calcein or labelling with europium that becomes fluorescent when released Eu3+ binds to a chelator. Fluorescence can be measured by means of multi-well fluorometers or by flow cytometry methods.
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The measurement approaches of end-point RT-PCR requires the detection of gene expression levels by the use of fluorescent dyes like ethidium bromide, P32 labeling of PCR products using phosphorimager, or by scintillation counting. End-point RT- PCR is commonly achieved using three different methods: relative, competitive and comparative. ; Relative RT-PCR: Relative quantifications of RT-PCR involves the co-amplification of an internal control simultaneously with the gene of interest. The internal control is used to normalize the samples.
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The applied electric field prevents recombination of all the electrons produced from a charged particle interaction in the TPC. These electrons are drifted to the top of the liquid phase by the electric field. The ionization is then extracted into the gas phase by the stronger electric field in the gaseous phase. The electric field accelerates the electrons to the point that it creates a proportional scintillation signal that is also collected by the PMTs, and is referred to as the S2 signal.
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The process of converting radioactivity to light requires a liquid medium of scintillation combination consisting soluble organic scintillators and organic solvents. During the process of radioactive decay, a beta particle will be released. While this particle travels in the medium, the energy it possesses is dissipated as it collides with the surrounding molecules in the solvent, exciting them while doing so. The excited molecules will transfer the energy they now possess to the scintillator molecules, where the energy will be emitted as light.
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The phosphorescence of ZnS was first reported by the French chemist Théodore Sidot in 1866. His findings were presented by A. E. Becquerel, who was renowned for the research on luminescence. ZnS was used by Ernest Rutherford and others in the early years of nuclear physics as a scintillation detector, because it emits light upon excitation by x-rays or electron beam, making it useful for X-ray screens and cathode ray tubes. This property made zinc sulfide useful in the dials of radium watches.
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It was the second of the Ye-1a series, modified to carry a heavier payload of and had a combined mass of . Luna 2 was similar in design to Luna 1, a spherical space probe with protruding antennas and instrumentation. The instrumentation was also similar to Luna 1, which included a triaxial fluxgate magnetometer, a piezoelectric detector, a scintillation counter, ion traps and two gas- discharge counters, while the Luna 2 included six gas-discharge counters. There were no propulsion systems on Luna 2 itself.
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Luna rocket Luna 2 carried five different types of instruments to conduct various tests while it was on its way to the Moon. The scintillation counters were used to measure any ionizing radiation and the Cherenkov radiation detectors to measure electromagnetic radiation caused by charged particles. The primary scientific purpose of the Geiger Counter carried on Luna 2 was to determine the electron spectrum of the Van Allen radiation belt. It consisted of three STS-5 gas-discharge counters mounted on the outside of an airtight container.
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5, No. 11, pp. 1921-1927 (1967) (doi: 10.2514/3.4341) Laurence E. Peterson, Instrumental Technique in X-Ray Astronomy, Annual Review of Astronomy and Astrophysics, 13, 423 (1975) Drawing of an active anticoincidence collimated scintillation spectrometer designed for gamma-ray astronomy in the energy range from 0.1 to 3 MeV. The proposed instrument is shown in the figure to the right. Frost developed this design in collaboration with Laurence E. Peterson, then at the University of Minnesota, who had been working independently on a similar idea.
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Measurement of gamma ray spectrum with a scintillation counter. A high voltage drives the counter which feeds signals to the Multichannel Analyser (MCA) and computer. Scintillators often convert a single photon of high energy radiation into high number of lower-energy photons, where the number of photons per megaelectronvolt of input energy is fairly constant. By measuring the intensity of the flash (the number of the photons produced by the x-ray or gamma photon) it is therefore possible to discern the original photon's energy.
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After receiving his doctorate, Steinberger attended the Institute for Advanced Study in Princeton for a year. In 1949 he published a calculation of the lifetime of the neutral pion, which anticipated the study of anomalies in quantum field theory. Following Princeton, Steinberger went to the Radiation Lab at the University of California at Berkeley, where he performed an experiment which demonstrated the production of neutral pions and their decay to photon pairs. This experiment utilized the 330 MeV synchrotron and the newly invented scintillation counters.
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Impurities in the crystals trap electrons and holes, ruining the performance of the detectors. Consequently, germanium crystals were doped with lithium ions (Ge(Li)), in order to produce an intrinsic region in which the electrons and holes would be able to reach the contacts and produce a signal. When germanium detectors were first developed, only very small crystals were available. Low efficiency was the result, and germanium detector efficiency is still often quoted in relative terms to a "standard" 3″ x 3″ NaI(Tl) scintillation detector.
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The scintillation process in inorganic materials is due to the electronic band structure found in crystals and is not molecular in nature as is the case with organic scintillators. An incoming particle can excite an electron from the valence band to either the conduction band or the exciton band (located just below the conduction band and separated from the valence band by an energy gap; see picture). This leaves an associated hole behind, in the valence band. Impurities create electronic levels in the forbidden gap.
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Gamma spectroscopy detectors are passive materials that are able to interact with incoming gamma rays. The most important interaction mechanisms are the photoelectric effect, the Compton effect, and pair production. Through these processes, the energy of the gamma ray is absorbed and converted into a voltage signal by detecting the energy difference before and after the interaction (or, in a scintillation counter, the emitted photons using a photomultiplier). The voltage of the signal produced is proportional to the energy of the detected gamma ray.
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Germanium gamma spectrum of a radioactive Am-Be-source. Semiconductor detectors, also called solid-state detectors, are fundamentally different from scintillation detectors: They rely on detection of the charge carriers (electrons and holes) generated in semiconductors by energy deposited by gamma ray photons. In semiconductor detectors, an electric field is applied to the detector volume. An electron in the semiconductor is fixed in its valence band in the crystal until a gamma ray interaction provides the electron enough energy to move to the conduction band.
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In 1957, Rossi asked Linsley to design a much larger array based on the principles of the Agassiz array. Linsley worked with Livio Scarsi from the University of Milan to build an array of nineteen plastic scintillation detectors at Volcano Ranch near Albuquerque, New Mexico. They began making observations in the summer of 1959. On February 22, 1962, Linsley observed an air shower created by a primary particle with an energy greater than 1020 eV, the highest energy cosmic ray particle ever detected at the time.
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Neutron absorption produces a tritium ion, an alpha particle, and kinetic energy. The alpha particle and triton interact with the glass matrix to produce ionization, which transfers energy to Ce3+ ions and results in the emission of photons with wavelength 390 nm - 600 nm as the excited state Ce3+ ions return to the ground state. The event results in a flash of light of several thousand photons for each neutron absorbed. A portion of the scintillation light propagates through the glass fiber, which acts as a waveguide.
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The hazards to people and the environment from radioactive contamination depend on the nature of the radioactive contaminant, the level of contamination, and the extent of the spread of contamination. Low levels of radioactive contamination pose little risk, but can still be detected by radiation instrumentation. If a survey or map is made of a contaminated area, random sampling locations may be labeled with their activity in becquerels or curies on contact. Low levels may be reported in counts per minute using a scintillation counter.
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The designer and inventor of the first South Africa origin patent cut diamonds registered in over 30 countries worldwide The My Girl diamond USA patent number US 29/175,153 dated January 30, 2003, is the flagship diamond for Shimansky currently sold exclusively at shimansky stores only. the only diamond in the world with the perfect balance of fire, brilliance and scintillation 33.33% in each area, making the diamond sparkle from every angle under any light condition shaping the internal light while absorbing external light to its maximum.
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Until recently, all these names referred to instruments operating up to about 100 Pa and with BSE detectors only. Lately, the Zeiss-SMT VP-SEM has been extended to higher pressure together with a gaseous ionization or gaseous scintillation as the SE mechanism for image formation. Therefore, it is improper to identify the term ESEM with one only brand of commercial instrument in juxtaposition to other competing commercial (or laboratory) brands with different names, as some confusion may arise from past use of trademarks.
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Neutrino-related experiments were started in KGF in 1964. The main goal was the detection of atmospheric neutrinos, with an understanding that cosmic rays contain high energy pions and muons which decay in the Earth's atmosphere to produce billions of neutrinos. The experiments were conducted by groups from TIFR, Durham University and Osaka University using basic trigger with scintillation counters and Neon Flash Tubes (NFT) for tracking detectors. Seven detectors were deployed at a depth of 2.3 km in Heathcote shaft and Champion Reefs mines.
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In a low-energy nuclear scattering experiment, it is conventional to refer to the nuclear recoil energy in units of eVr, keVr, etc. This distinguishes the nuclear recoil energy from the "electron equivalent" recoil energy (eVee, keVee, etc.) measured by scintillation light. For example, the yield of a phototube is measured in phe/keVee (photoelectrons per keV electron-equivalent energy). The relationship between eV, eVr, and eVee depends on the medium the scattering takes place in, and must be established empirically for each material.
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Gamma rays given off from naturally occurring radioactive elements bombard the scintillation detector mounted on the tool. The tool processes the gamma ray counts and sends the data uphole where it processed by a computerized acquisition system, and plotted on a log versus depth. The information is then used to ensure that the depth shown on the log is correct. After that, power can be applied through the tool to set off explosive charges for things like perforating, setting plugs or packers, dumping cement, etc.
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McDonald was born in Columbus, Georgia to Frank B. McDonald and Lucy Kyle McDonald. After he graduated from Duke University in 1948, he attended the University of Minnesota where he obtained a master's degree in 1951. Here, under the supervision of Edward P. Ney, he completed a doctorate in physics in 1955. For his thesis, he carried out balloon flights to the top of the atmosphere of a cloud chamber triggered by a scintillation counter to study the charge distribution of primary cosmic rays.
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In 1996 Boris Grinyov was one of the recipients of the National Award of Ukraine in Science and Technology (uk) for “Development of technology for industrial production of large scintillation crystals for various applications”. He was conferred on title of Honored Scientist and Technician of Ukraine in 1998. He was awarded an Order of Merit of the third degree in 2006, and the second degree in 2009, and the first degree in 2013. In 2002 B. Grinyov was awarded Ukrainian Cabinet of Ministers’ Charter.
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1, 2019. DOI: 10.3847/1538-4357/ab46aa, Jovian Io-related decametric radiation, ionospheric scintillation, emission of pulsars, etc. The presence of large and well-studied UTR-2 at the same observatory opens vast opportunities in antenna testing in the shared frequency rangeZakharenko, V., Yerin, S., Bubnov, I., Vasilieva, I. and Kravtsov, I., 2016, October. Using of pulsar spectra catalogue at frequencies below 80 MHz for astronomical calibration of phased antenna arrays. In Applied Physics and Engineering (YSF), 2016 II International Young Scientists Forum on (pp. 210-213).
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Older gamma-ray detectors use the Geiger-Mueller counter principle, but have been mostly replaced thallium-doped sodium-iodide (NaI) scintillation detector, which has a higher efficiency. NaI detectors are usually composed of a NaI crystal coupled with a photomultiplier. When gamma ray from formation enters the crystal, it undergoes successive collisions with the atoms of the crystal, resulting in a short flashes of light when the gamma-ray is absorbed. The light is detected by the photomultiplier, which converts the energy into an electric pulse with amplitude proportional to the gamma-ray energy.
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The primary phosphor will emit photons following absorption of the transferred energy. Because that light emission may be at a wavelength that does not allow efficient detection, many cocktails contain secondary phosphors that absorb the fluorescence energy of the primary phosphor and re- emit at a longer wavelength. The radioactive samples and cocktail are placed in small transparent or translucent (often glass or plastic) vials that are loaded into an instrument known as a liquid scintillation counter. Newer machines may use 96-well plates with individual filters in each well.
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During the past two decades, additional types of transparent ceramics have been developed for applications such as nose cones for heat-seeking missiles, windows for fighter aircraft, and scintillation counters for computed tomography scanners. In the early 1970s, Thomas Soules pioneered computer modeling of light transmission through translucent ceramic alumina. His model showed that microscopic pores in ceramic, mainly trapped at the junctions of microcrystalline grains, caused light to scatter and prevented true transparency. The volume fraction of these microscopic pores had to be less than 1% for high-quality optical transmission.
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The scintillator consists of a transparent crystal, usually a phosphor, plastic (usually containing anthracene) or organic liquid (see liquid scintillation counting) that fluoresces when struck by ionizing radiation. Cesium iodide (CsI) in crystalline form is used as the scintillator for the detection of protons and alpha particles. Sodium iodide (NaI) containing a small amount of thallium is used as a scintillator for the detection of gamma waves and zinc sulfide (ZnS) is widely used as a detector of alpha particles. Zinc sulfide is the material Rutherford used to perform his scattering experiment.
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As Wheaton Industries, the company manufactured a wide variety of commercial products, many of which have become collectors items. The present subsidiary of Alcan Packaging has a more limited product line aimed at laboratory applications. It specializes in containers and vial products from both Type I borosilicate glass and Type III soda lime glass, as well as plastic resins. The company also manufactures a BOD (Biochemical Oxygen Demand) bottle that is popular in the international market, as well as glass scintillation vials and a wide variety of glass and plastic rigid containers and closures.
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Comparison of threshold triggering (left) and constant fraction triggering (right) A constant fraction discriminator (CFD) is an electronic signal processing device, designed to mimic the mathematical operation of finding a maximum of a pulse by finding the zero of its slope. Some signals do not have a sharp maximum, but short rise times t_r. Typical input signals for CFDs are pulses from plastic scintillation counters, such as those used for lifetime measurement in positron annihilation experiments. The scintillator pulses have identical rise times that are much longer than the desired temporal resolution.
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They are used as scintillators in particle physics because of their short radiation length (0.89 cm), low Molière radius (2.2 cm), quick scintillation response, and radiation hardness. Lead tungstate crystals are used in the Compact Muon Solenoid's electromagnetic calorimeter. It was first described in 1820 by August Breithaupt, who called it Scheelbleispath and then by François Sulpice Beudant in 1832, who called it scheelitine. In 1845, Wilhelm Karl Ritter von Haidinger coined the name stolzite for an occurrence in Krusne Hory (Erzgebirge), Czech Republic, naming it after Joseph Alexi Stolz of Teplice in Bohemia.
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Alpha scintillation probe for detecting surface contamination under calibration Scintillators are used by the American government as Homeland Security radiation detectors. Scintillators can also be used in particle detectors, new energy resource exploration, X-ray security, nuclear cameras, computed tomography and gas exploration. Other applications of scintillators include CT scanners and gamma cameras in medical diagnostics, and screens in older style CRT computer monitors and television sets. Scintillators have also been proposed as part of theoretical models for the harnessing of gamma-ray energy through the photovoltaic effect, for example in a nuclear battery.
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These are liquid solutions of one or more organic scintillators in an organic solvent. The typical solutes are fluors such as p-terphenyl (), PBD (), butyl PBD (), PPO (), and wavelength shifter such as POPOP (). The most widely used solvents are toluene, xylene, benzene, phenylcyclohexane, triethylbenzene, and decalin. Liquid scintillators are easily loaded with other additives such as wavelength shifters to match the spectral sensitivity range of a particular PMT, or 10B to increase the neutron detection efficiency of the scintillation counter itself (since 10B has a high interaction cross section with thermal neutrons).
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Gaseous scintillators consist of nitrogen and the noble gases helium, argon, krypton, and xenon, with helium and xenon receiving the most attention. The scintillation process is due to the de-excitation of single atoms excited by the passage of an incoming particle. This de-excitation is very rapid (~1 ns), so the detector response is quite fast. Coating the walls of the container with a wavelength shifter is generally necessary as those gases typically emit in the ultraviolet and PMTs respond better to the visible blue-green region.
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Elektron 1 and 3 had design masses of , were in diameter, and were designed to be placed into eccentric × orbits. They were cylindrical with six solar panels with a combined area of 20 m2 for power generation. The experiment packages for Elektron 1 and 3 were identical, each including a radio frequency mass spectrometer; Geiger counters, scintillation counters, and semiconductor detectors for radiation studies; a piezoelectric micrometeoroid detector; a galactic radio-noise receiver, and a radio beacon for ionospheric studies. Telemetry and commands were conveyed via four antennas.
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The instruments are designed to be hand-held, are battery powered and of low mass to allow easy manipulation. Other features include an easily readable display, in counts or radiation dose, and an audible indication of the count rate. This is usually the “click” associated with the Geiger type instrument, and can also be an alarm warning sound when a rate of radiation counts or dose has been exceeded. For dual channel detectors such as the scintillation detector it is normal to generate different sounds for alpha and beta.
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Schematic designs of the scintillation and AIROBICC counters Another detector type for Cherenkov light was AIROBICC (AIRshower Observation By angle Integrating Cherenkov Counters) with one large photomultiplier looking at the sky above it. 49 of these detectors were spread in a 7-by-7 grid to observe the amplitude and the time of arrival of the front of Cherenkov light. Another 48 were added later on. These counters had a wide field of view but could only be operated during clear, moonless nights, like the atmospheric Cherenkov telescopes.
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Cross-hatching is perhaps one of the most distinctive and beautiful features of Yolngu art. Closely spaced fine lines are drawn in particular colours, intersecting each other. The chosen colours may be a specific to a particular clan, and the effect is difficult to describe, but produces a deep impression on the viewer. Traditionally, the most sacred designs drawn on bodies during ceremonies were drawn with a quality called “bir’yun”, which is loosely translated as scintillation (as in the twinkling of stars) but carries a connotation of sunlight reflected off sparkling water.
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The primary objective of the SAS-B was to measure the spatial and energy distribution of primary galactic and extragalactic gamma radiation which energies between 20 and 300 MeV. The instrumentation consisted principally of a guard scintillation detector, an upper and a lower spark chamber, and a charged particle telescope. SAS-2 was launched from the San Marco platform off the coast of Malindi, Kenya, into a nearly equatorial orbit. The orbiting spacecraft was in the shape of a cylinder approximately 59 cm in diameter and 135 cm in length.
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Sodium Iodide crystal co-doped with Thallium and Lithium [NaI(Tl+Li)] a.k.a. NaIL has the ability to detect Gamma radiation and Thermal Neutrons in a single crystal with exceptional Pulse-shape Discrimination.The use of low 6Li concentrations in NaIL and large thicknesses can achieve the same neutron detection capabilities as 3He or CLYC or CLLB detectors at a lower cost.6Li (95% enriched) co-doping introduces efficient thermal neutron detection to the most established gamma-ray scintillator while retaining the favorable scintillation properties of standard NaI(Tl).
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The thymidine is incorporated into dividing cells and the level of this incorporation, measured using a liquid scintillation counter, is proportional to the amount of cell proliferation. For example, lymphocyte proliferation can be measured this way in lymphoproliferative disorders. Bromodeoxyuridine (BrdU) is another thymidine analog that is often used for the detection of proliferating cells in living tissues. 5-Ethynyl-2´-deoxyuridine (EdU) is a thymidine analog which is incorporated into the DNA of dividing cells and is used to assay DNA synthesis in cell culture or living tissues.
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CH-47 Chinook helicopter in Afghanistan The Kopp–Etchells effect is a sparkling ring or disk that is sometimes produced by rotary-wing aircraft when operating in desert conditions, particularly near the ground at night. The name was coined by photographer Michael Yon to honor two soldiers who were killed in combat; Benjamin Kopp, a US Army Ranger, and Joseph Etchells, a British soldier. Both were killed in combat in Sangin, Afghanistan in July of 2009. Other names that have been used to describe this phenomenon include scintillation, halo effect, pixie dust, and corona effect.
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These particles as well as muons can be easily detected by many types of particle detectors, such as cloud chambers, bubble chambers, water-Cherenkov or scintillation detectors. The observation of a secondary shower of particles in multiple detectors at the same time is an indication that all of the particles came from that event. Cosmic rays impacting other planetary bodies in the Solar System are detected indirectly by observing high-energy gamma ray emissions by gamma-ray telescope. These are distinguished from radioactive decay processes by their higher energies above about 10 MeV.
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Reddick decoded the entire message after approximately twelve hours of work. This was followed by an attempt to extend the syntax used in the Lone Signal hailing message to communicate in a way that, while neither mathematical nor strictly logical, was nonetheless understandable given the prior definition of terms and concepts in the hailing message. Also characteristics of the radio signal such as wavelength, type of polarization, and modulation have to be considered. Over galactic distances, the interstellar medium induces some scintillation effects and artificial modulation of electromagnetic signals.
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Quantum 1/f noise is an intrinsic and fundamental part of quantum mechanics. Fighter pilots, photographers, and scientists all appreciate the higher quality of images and signals resulting from the consideration of quantum 1/f noise. Engineers have battled unwanted 1/f noise since 1925, giving it poetic names (such as flicker noise, funkelrauschen, bruit de scintillation, etc.) due to its mysterious nature. The Quantum 1/f noise theory was developed about 50 years later, describing the nature of 1/f noise, allowing it the be explained and calculated via straightforward engineering formulas.
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The DEAP-3600 detector was designed to use 3600 kg of liquid argon, with a 1000 kg fiducial volume, the remaining volume is used as self- shielding and background veto. This is contained in a ~2 m diameter spherical acrylic vessel, the first of its kind ever created. The acrylic vessel is surrounded by 255 high quantum efficiency photomultiplier tubes (PMTs) to detect the argon scintillation light. The acrylic vessel is housed in a stainless steel shell submerged in a 7.8m diameter shield tank filled with ultra-pure water.
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Improved sensitivity to dark matter was achieved in February 2019, with an analysis of data collected over 231 live days from the second fill in 2016-2017, giving a cross-section limit of 3.9×10−45 cm2 for a 100 GeV/c2 WIMP mass. This updated analysis demonstrated the best performance ever achieved in liquid argon at threshold, for the pulse-shape discrimination technique against beta and gamma backgrounds. The collaboration also developed new techniques to reject rare nuclear recoil backgrounds, using the observed distribution of light in space and time after a scintillation event.
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Compared to xenon, argon is cheaper and has a distinct scintillation time profile, which allows the separation of electronic recoils from nuclear recoils. On the other hand, its intrinsic beta-ray background is larger due to contamination, unless one uses argon from underground sources, which has much less contamination. Most of the argon in the Earth's atmosphere was produced by electron capture of long-lived ( + e− → + ν) present in natural potassium within the Earth. The activity in the atmosphere is maintained by cosmogenic production through the knockout reaction (n,2n) and similar reactions.
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The consequence of this analysis is that the secondary electrons are possible to detect in a gaseous environment even at high pressures, depending on the engineering efficacy of any given instrument. As a further characteristic of the GDD, a gaseous scintillation avalanche also accompanies the electron avalanche and, by detection of the light produced with a photo-multiplier, corresponding SE images can be routinely made. The frequency response of this mode has allowed the use of true TV scanning rates. This mode of the detector has been employed by a latest generation of commercial instruments.
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The chamber was patented and that quickly superseded the old bubble chambers, allowing for better data processing. This new creation had been made public during 1968.IEEEieeeghn Retrieved 2012-01-29 Charpak was later to become a joint inventor with Nlolc and Policarpo of the scintillation drift chamber during the latter parts of the 1970s.Elena Aprile, Aleksey E. Bolotnikov, Alexander I. Bolozdynya, Tadayoshi Doke - Noble Gas Detectors - 362 pages John Wiley & Sons, 28 May 2007 (Google eBook) Retrieved 2012-01-29 He eventually retired from CERN in 1991.
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That Bell did not receive recognition in the 1974 Nobel Prize in Physics has been a point of controversy ever since. She helped build the Interplanetary Scintillation Array over two years and initially noticed the anomaly, sometimes reviewing as much as of paper data per night. Bell later said that she had to be persistent in reporting the anomaly in the face of scepticism from Hewish, who was initially insistent that it was due to interference and man-made. She spoke of meetings held by Hewish and Ryle to which she was not invited.
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Botanical prospecting for uranium is a method of finding uranium deposits either by observation of plant life growing on the surface, or by geochemical analysis of plant material. The history of uranium prospecting, especially in the Colorado Plateau of North America, has seen several methods of identifying likely ore body locations. The use of radiation detectors, such as Geiger counters and scintillation counter is one such method. Another method widely used relies on knowledge of the geologic history of an area, such as locating a geologic formation known to host ore deposits.
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A nuclear level gauge or gamma ray gauge measures level by the attenuation of gamma rays passing through a process vessel. The technique is used to regulate the level of molten steel in a continuous casting process of steelmaking. The water-cooled mold is arranged with a source of radiation, such as cobalt-60 or caesium-137, on one side and a sensitive detector such as a scintillation counter on the other. As the level of molten steel rises in the mold, less of the gamma radiation is detected by the sensor.
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Once contamination has been removed, samples must be converted to a form suitable for the measuring technology to be used. A common approach is to produce a gas, for gas counting devices: is widely used, but it is also possible to use other gases, including methane, ethane, ethylene and acetylene.Aitken, Science-based Dating in Archaeology, pp. 76-78. For samples in liquid form, for use in liquid scintillation counters, the carbon in the sample is converted to benzene, though other liquids were tried during the early decades of the technique.
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A faceted spodumene, with reflecting internal inclusion. The art of cutting a gem is an exacting procedure performed on a faceting machine. The ideal product of facet cutting is a gemstone that displays a pleasing balance of internal reflections of light known as brilliance, strong and colorful dispersion which is commonly referred to as "fire", and brightly colored flashes of reflected light known as scintillation. Typically transparent to translucent stones are faceted, although opaque materials may occasionally be faceted as the luster of the gem will produce appealing reflections.
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These wire planes are made up of 240 parallel wires with a separation of 4mm. A third wire plane of 225 wires, aligned along the vertical axis, is placed in front of the other two planes in order to prevent the electric field from interfering with the instrumentation. Ionization of liquid argon emits characteristic 128 nm light (in the violet/ultraviolet range), which is detected by a scintillation read-out system. This system has a high efficiency, having been designed using systems developed for dark matter liquid argon detectors.
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Other methods of image localization (pinhole, rotating slat collimator with CZT) have been proposed and tested; however, none have entered widespread routine clinical use. The best current camera system designs can differentiate two separate point sources of gamma photons located at 6 to 12 mm depending on distance from the collimator, the type of collimator and radio-nucleide. Spatial resolution decreases rapidly at increasing distances from the camera face. This limits the spatial accuracy of the computer image: it is a fuzzy image made up of many dots of detected but not precisely located scintillation.
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In a significant test, his detectors validated the feasibility of making the hydrogen bomb. At a time when electronics had not been able to make measurements with nanosecond accuracy, he developed several techniques to accomplish this accuracy for measuring organic fluorescence decay times and organic scintillation pulse widths by indirect means. His 1947 invention of the use of halogen gas in Geiger–Müller tubes led to considerable benefits in reducing the voltage of operation and greatly extended the life of the tubes. All modern GM tubes use his halogen-based quench gas.
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Jones' research has involved not only particle accelerator design and experiments at proton accelerators, but also detector development and cosmic ray research. He collaborated in the 1950s in the Midwestern Universities Research Association (MURA), which developed the concept of colliding beams in modern particle accelerators. He contributed to development of the scintillation chamber, optical spark chamber, and the ionization calorimeter for hadron energy measurement. He participated in experiments on hadron cross- sections as well as elastic and inelastic scattering and production of particles, dimuons, neutrinos, and proton charm production.
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Scintillation proximity assay (SPA) is an assay development and biochemical screening that permits the rapid and sensitive measurement of a broad range of biological processes in a homogeneous system. The type of beads that are involved in the SPA are microscopic in size and within the beads itself, there is a scintillant which emits light when it is stimulated. Stimulation occurs when radio-labelled molecules interact and bind to the surface of the bead. This interaction will trigger the bead to emit light, which can be detected using a photometer.
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Whole body monitor in use. If a gamma ray is emitted from a radioactive element within the human body due to radioactive decay, and its energy is sufficient to escape then it can be detected. This would be by means of either a scintillation detector or a semiconductor detector placed in close proximity to the body. Radioactive decay may give rise to gamma radiation which cannot escape the body due to being absorbed or other interaction whereby it can lose energy; so account must be taken of this in any measurement analysis.
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Seliger used his measurement techniques for photon scintillation to make the first measurement of the quantum yield of the firefly light reaction. This was the beginning of his outstanding achievements in the study of bioluminescence in fireflies, bacteria, phytoplankton, fish, and ctenophores. Seliger, as part of a team of Johns Hopkins scientists, studied more than 100 different species of fireflies in Maryland and on the island of Jamaica. He built an instrument, called by him a "firefly gun," which his team used in making the first measurements of the specific flash patterns of various firefly species in their natural habitat.
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The way to perform this simulation is explained in detail in paper by D. Cano-Ott et al. GEANT3 and GEANT4 are well suited for these kind of simulations. If the scintillator material of the TAS detector suffers from a non proportionality in the light production, the peaks produced by a cascade will be displaced further for every increment in the multiplicity and the width of these peaks will be different from the width of single peaks with the same energy. This effect can be introduced in the simulation by means of a hyperbolic scintillation efficiency.
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The technique of using 14C incorporation (added as labelled Na2CO3) to infer primary production is most commonly used today because it is sensitive, and can be used in all ocean environments. As 14C is radioactive (via beta decay), it is relatively straightforward to measure its incorporation in organic material using devices such as scintillation counters. Depending upon the incubation time chosen, net or gross primary production can be estimated. Gross primary production is best estimated using relatively short incubation times (1 hour or less), since the loss of incorporated 14C (by respiration and organic material excretion / exudation) will be more limited.
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ZEPLIN-III experiment: the WIMP detector, built mainly out of copper, included two chambers within a cryostat vessel: the upper one contained 12 kg of active liquid xenon; an array of 31 photomultipliers operated immersed in the liquid to detect prompt scintillation as well as delayed electroluminescence from a thin gas layer above the liquid. The lower chamber contained liquid nitrogen to provide cooling. The detector was surrounded by Gd-loaded polypropylene to moderate and capture neutrons, a potential source of background. The gamma- rays from neutron capture were detected by 52 modules of plastic scintillator placed around the moderator.
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The Ranger 1 and 2 Block I missions were virtually identical. Spacecraft experiments included a Lyman-alpha telescope, a rubidium-vapor magnetometer, electrostatic analyzers, medium-energy-range particle detectors, two triple coincidence telescopes, a cosmic-ray integrating ionization chamber, cosmic dust detectors, and scintillation counters. The goal was to place these Block I spacecraft in a very high Earth orbit with an apogee of and a perigee of . From that vantage point, scientists could make direct measurements of the magnetosphere over a period of many months while engineers perfected new methods to routinely track and communicate with spacecraft over such large distances.
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By the time of the Bagnères-de-Bigorre conference, Rossi had already turned his attention toward the astrophysical implications of cosmic ray phenomena, particularly extensive air showers. After Rossi's recognition, in Eritrea, that these events exist, they were extensively studied by Pierre Auger, and by Williams. At this time, the extremely fast response of the newly developed scintillation counters offered a new way to study the structure of air showers. To do this, Rossi enlisted his student, George W. Clark, who completed a PhD in 1952, and Piero Bassi, who was a visitor from the University of Padua.
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A high-gain directional dish antenna was attached to the bottom of the base. Spacecraft experiments and other equipment were mounted on the base and tower. Instruments aboard the spacecraft included a Lyman-alpha telescope, a rubidium-vapor magnetometer, electrostatic analyzers, medium-energy-range particle detectors, two triple coincidence telescopes, a cosmic-ray integrating ionization chamber, cosmic dust detectors, and scintillation counters. The communications system included the high-gain antenna and an omnidirectional medium-gain antenna and two transmitters at approximately 960 MHz, one with 0.25 W power output and the other with 3 W power output.
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While light from stars and other astronomical objects are likely to twinkle, twinkling usually does not cause images of planets to flicker appreciably.Kenyon, S. L.; Lawrence, M. et al; "Atmospheric Scintillation at Dome C, Antarctica", Astronomical Society of the Pacific 118, 924–932. Stars twinkle because they are so far from Earth that they appear as point sources of light easily disturbed by Earth's atmospheric turbulence, which acts like lenses and prisms diverting the light's path. Large astronomical objects closer to Earth, like the Moon and other planets, encompass many points in space and can be resolved as objects with observable diameters.
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Soft tissue does not affect the results of bone tissue measurement. Therefore, the absorption coefficient of a beam of constant energy radiation can be calculated beforehand, and the intensity of radiation (or counting) can be obtained directly in patients' measurement. In the vertical C-frame, the collimated 125I light source (200 mCi or 74 GBq) and the collimated NaI (TI) scintillation detector-photomultiplier tube are mounted in relative geometric shapes to place the measured body parts between the source and the detector. The source and detector assembly are rigidly connected and driven by a motor to cross the longitudinal axis of the bone.
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The resulting positron annihilate with electrons, creating pairs of coincident photons with an energy of about 0.5 MeV each, which could be detected by the two scintillation detectors above and below the target. The neutrons were captured by cadmium nuclei resulting in delayed gamma rays of about 8 MeV that were detected a few microseconds after the photons from a positron annihilation event. This experiment was designed by Cowan and Reines to give a unique signature for antineutrinos, to prove the existence of these particles. It was not the experimental goal to measure the total antineutrino flux.
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Scintillation detectors use crystals that emit light when gamma rays interact with the atoms in the crystals. The intensity of the light produced is usually proportional to the energy deposited in the crystal by the gamma ray; a well known situation where this relationship fails is the absorption of <200keV radiation by intrinsic and doped sodium iodide detectors. The mechanism is similar to that of a thermoluminescent dosimeter. The detectors are joined to photomultipliers; a photocathode converts the light into electrons; and then by using dynodes to generate electron cascades through delta ray production, the signal is amplified.
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A hodoscope (from the Greek "hodos" for way or path, and "skopos" an observer) is an instrument used in particle detectors to detect passing charged particles and determine their trajectories. Hodoscopes are characterized by being made up of many segments; the combination of which segments record a detection is then used to infer where the particle passed through hodoscope. The typical detector segment is a piece of scintillating material, which emits light when a particle passes through it. The scintillation light can be converted to an electrical signal either by a photomultiplier tube (PMT) or a PIN diode.
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DEAP-3600 detector during construction in 2014 DEAP (Dark matter Experiment using Argon Pulse-shape discrimination) is a direct dark matter search experiment which uses liquid argon as a target material. DEAP utilizes background discrimination based on the characteristic scintillation pulse- shape of argon. A first-generation detector (DEAP-1) with a 7 kg target mass was operated at Queen's University to test the performance of pulse-shape discrimination at low recoil energies in liquid argon. DEAP-1 was then moved to SNOLAB, 2 km below Earth's surface, in October 2007 and collected data into 2011.
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The A4, or Hard X-ray / Low Energy Gamma-ray Experiment, used sodium iodide (NaI) scintillation counters to cover the energy range from about 20 keV to 10 MeV.Peterson, Laurence E, Instrumental Technique in X-Ray Astronomy. in Annual Review of Astronomy and Astrophysics 13, 423 (1975) It consisted of seven clustered modules, of three distinct designs, in a roughly hexagonal array.HEASARC HEAO 1 Each detector was actively shielded by surrounding CsI scintillators, in active-anti- coincidence, so that an extraneous particle or gamma-ray event from the side or rear would be vetoed electronically, and rejected.
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Bi4Ge3O12 has a cubic crystal structure (a = 1.0513 nm, z = 4, Pearson symbol cI76, space group I3d No. 220) and a density of 7.12 g/cm3. When irradiated by X-rays or gamma rays it emits photons of wavelengths between 375 and 650 nm, with peak at 480 nm it produces about 8500 photons per megaelectronvolt of the high energy radiation absorbed. It has good radiation hardness (parameters remaining stable up to 5.104 Gy), high scintillation efficiency, good energy resolution between 5 and 20 MeV, is mechanically strong, and is not hygroscopic. Its melting point is 1050 °C.
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Schematic view of a pulsar. The sphere in the middle represents the neutron star, the curves indicate the magnetic field lines and the protruding cones represent the emission beams. The first pulsar was discovered in 1967 by Jocelyn Bell and her PhD supervisor Antony Hewish using the Interplanetary Scintillation Array. Shortly after the discovery of pulsars, Franco Pacini and Thomas Gold independently suggested that pulsars are highly magnetized rotating neutron stars, which form as a result of a supernova at the end of the life stars more massive than about 10 times the mass of the Sun.
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Usually, temperature, pressure, wind measurements, and humidity are the variables that are measured by a thermometer, barometer, anemometer, and hygrometer, respectively. Professional stations may also include air quality sensors (carbon monoxide, carbon dioxide, methane, ozone, dust, and smoke), ceilometer (cloud ceiling), falling precipitation sensor, flood sensor, lightning sensor, microphone (explosions, sonic booms, thunder), pyranometer/pyrheliometer/spectroradiometer (IR/Vis/UV photodiodes), rain gauge/snow gauge, scintillation counter (background radiation, fallout, radon), seismometer (earthquakes and tremors), transmissometer (visibility), and a GPS clock for data logging. Upper air data are of crucial importance for weather forecasting. The most widely used technique is launches of radiosondes.
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The scintillation X-ray detector (XC) aboard Vela 5A and its twin Vela 5B consisted of two 1 mm thick NaI(Tl) crystals mounted on photomultiplier tubes and covered by a 0.13 mm thick beryllium window. Electronic thresholds provided two energy channels, 3–12 keV and 6–12 keV. In addition to the x-ray Nova announcement indicated above the XC Detector aboard Vela 5A and 5B also discovered and announced the first X-Ray Burst ever reported. The announcement of this discovery predated the initial announcement of the discovery of gamma-ray bursts by 2 years.
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Therefore, the radioactive isotope can be present in low concentration and its presence detected by sensitive radiation detectors such as Geiger counters and scintillation counters. George de Hevesy won the 1943 Nobel Prize for Chemistry "for his work on the use of isotopes as tracers in the study of chemical processes". There are two main ways in which radioactive tracers are used # When a labeled chemical compound undergoes chemical reactions one or more of the products will contain the radioactive label. Analysis of what happens to the radioactive isotope provides detailed information on the mechanism of the chemical reaction.
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The 250-680 nm spectral domain is used for the determination of O3, NO2, NO3−, aerosols and temperature. In addition, two high spectral resolution channels centred at 760 and 940 nm allow measurements of O2 and H2O and two fast photometers are used to correct star scintillation perturbations and to determine high vertical resolution temperature profiles. Global latitude coverage is obtained with up to 40 stellar occultations per orbit from South Pole to North Pole. Data acquired on dark limb (night-time) are of better quality than on bright limb (day-time) because of a smaller perturbation by background light.
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L'Annunziata & Kessler (2012), p. 424. For both the gas proportional counter and liquid scintillation counter, what is measured is the number of beta particles detected in a given time period. Since the mass of the sample is known, this can be converted to a standard measure of activity in units of either counts per minute per gram of carbon (cpm/g C), or becquerels per kg (Bq/kg C, in SI units). Each measuring device is also used to measure the activity of a blank sample – a sample prepared from carbon old enough to have no activity.
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As a result, during the third Soviet sputnik, he discovered the Earth's radiation belts in collaboration with S. N. Vernov. In 1961 Chudakov and G. T. Zatsepin suggested the air Chernkov method for the gamma-ray astronomy and carried out a pioneering experiment at Katsively, Crimea. From the mid-1960s Chudakov headed the design and construction of the Baksan Underground Scintillation Telescope, which was put into operation in 1978 and considered to be one of the first large multipurpose facilities for underground physics. In astroparticle physics the first class results have been obtained with this telescope which is still in operation.
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Patients swallow urea labelled with an uncommon isotope, either radioactive carbon-14 or non-radioactive carbon-13. In the subsequent 10–30 minutes, the detection of isotope-labelled carbon dioxide in exhaled breath indicates that the urea was split; this indicates that urease (the enzyme that H. pylori uses to metabolize urea) is present in the stomach, and hence that H. pylori bacteria are present. For the two different forms of urea, different instrumentation is required. Carbon-14 is normally measured by scintillation, whereas carbon-13 can be detected by isotope ratio mass spectrometry or by mass correlation spectrometry.
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On the initiative and under the direction of B. Grinyov the production of very pure single crystals of salts was organized in Ukraine. And this production provided a stable export of high technology products such as scintillators based on alkali metal halides. He also directs the research which purpose is to search for new scintillation materials for experiments to search for "dark matter" and the double β-decay. In recent years under the B. Grinyov’s direction there were invented a number of new scintillator materials, which can find its application in the basis of new experiments in high-energy physics.
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The XENON dark matter research project, operated at the Italian Gran Sasso National Laboratory, is a deep underground research facility featuring increasingly ambitious experiments aiming to detect dark matter particles. The experiments aim to detect particles in the form of weakly interacting massive particles (WIMPs) by looking for rare interactions via nuclear recoils in a liquid xenon target chamber. The current detector consists of a dual phase time projection chamber (TPC). The experiment detects scintillation and ionization produced when particles interact in the liquid xenon volume, to search for an excess of nuclear recoil events over known backgrounds.
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The Baksan Neutrino Observatory (BNO) is a scientific laboratory of INR RAS located in the Baksan River gorge in the Caucasus mountains in Russia. Cleared for building in 1967, it started operations in 1977, becoming the first such neutrino observatory in the USSR. It consists of the Baksan Underground Scintillation Telescope (BUST), located below the surface, the gallium–germanium neutrino telescope (Soviet–American Gallium Experiment, SAGE) located 4,700 m.w.e. deep (2100 meters) as well as a number of ground facilities. The Baksan Experiment on Sterile Transitions (BEST) is currently (2019) being conducted at Baksan with aims of understanding sterile neutrinos.
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Hand-held large area alpha scintillation probe under calibration using a plate source Calibration sources are used primarily for the calibration of radiometric instrumentation, which is used on process monitoring or in radiological protection. Capsule sources, where the radiation effectively emits from a point, are used for beta, gamma and X-ray instrument calibration. High level sources are normally used in a calibration cell: a room with thick walls to protect the operator and the provision of remote operation of the source exposure. The plate source is in common use for the calibration of radioactive contamination instruments.
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The hybrid setup of the Telescope Array project allows for simultaneous observation of both the longitudinal development and the lateral distribution of the air showers. When a cosmic ray passes through the earth's atmosphere and triggers an air shower, the fluorescence telescopes measure the scintillation light generated as the shower passes through the gas of the atmosphere, while the array of scintillator surface detectors samples the footprint of the shower when it reaches the Earth's surface. At the center of the ground array is the Central Laser Facility which is used for atmospheric monitoring and calibrations.
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When the Doppler shift canceled out the gravitational blueshift, the receiving sample absorbed gamma rays and the number of gamma rays detected by the scintillation counter dropped accordingly. The variation in absorption could be correlated with the phase of the speaker vibration, hence with the speed of the emitting sample and therefore the Doppler shift. To compensate for possible systematic errors, Pound and Rebka varied the speaker frequency between 10 Hz and 50 Hz, interchanged the source and absorber-detector, and used different speakers (ferroelectric and moving coil magnetic transducer). The reason for exchanging the positions of the absorber and the detector is doubling the effect.
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The primary payload, the Compton Gamma Ray Observatory (CGRO), was deployed on flight day 3. CGRO's high-gain antenna failed to deploy on command; it was finally freed and manually deployed by Ross and Apt during an unscheduled contingency space walk, the first since April 1985. The following day, the two astronauts performed the first scheduled space walk since November 1985 to test means for astronauts to move themselves and equipment about while maintaining the then- planned Space Station Freedom. CGRO science instruments were Burst and Transient Source Experiment (BATSE), Imaging Compton Telescope (COMPTEL), Energetic Gamma Ray Experiment Telescope (EGRET) and Oriented Scintillation Spectrometer Experiment (OSSE).
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The first radio pulsar was discovered in 1967 by Jocelyn Bell and her adviser, Antony Hewish using the Interplanetary Scintillation Array. Franco Pacini and Thomas Gold quickly put forth the idea that pulsars are highly magnetized rotating neutron stars, which form as a result of a supernova at the end of the life of stars more massive than about 10 times the mass of the Sun (). The radiation emitted by pulsars is caused by interaction of the plasma surrounding the neutron star with its rapidly rotating magnetic field. This interaction leads to emission "in the pattern of a rotating beacon," as emission escapes along the magnetic poles of the neutron star.
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Very few applications existed for caesium until the 1920s, when it came into use in radio vacuum tubes, where it had two functions; as a getter, it removed excess oxygen after manufacture, and as a coating on the heated cathode, it increased the electrical conductivity. Caesium was not recognized as a high-performance industrial metal until the 1950s. Applications for nonradioactive caesium included photoelectric cells, photomultiplier tubes, optical components of infrared spectrophotometers, catalysts for several organic reactions, crystals for scintillation counters, and in magnetohydrodynamic power generators. Caesium also was, and still is, used as a source of positive ions in secondary ion mass spectrometry (SIMS).
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The scientific instruments consisted of an ion chamber and Geiger-Müller tube to measure total radiation flux, a proportional radiation counter telescope to measure high energy radiation, a scintillation counter to monitor low-energy radiation, a VLF receiver for natural radio waves, a transponder to study electron density, and part of the television facsimile system and flux-gate and search coil magnetometers mounted on the instrument platform. The television camera pointed through a small hole in the sphere between two of the solar panel mounts. The micrometeorite detector was mounted on the sphere as well. The total mass of the science package including electronics and power supply was 55 kg.
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By siting an SZA antenna near each of the CARMA antennas and observing a compact astronomical radio source near the source under study, the properties of the atmosphere could be measured on time scales as short as a couple of seconds. This information could be used in the data reduction process to remove a significant fraction of the degradation caused by the atmospheric scintillation. Observations using the SZA (operating at 30 GHz) to make the atmospheric measurements started in November 2008. The SZA has also participated directly in the science operations of CARMA during experiments where all three types of telescopes were attached to the same correlator.
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They did not find them, but in 1960, James Earl, who joined the Minnesota group in 1958, used similar apparatus to discover a small primary electron component. During the decade from 1950 to 1960, Ney's cosmic ray research shifted away from cloud chambers toward emulsions. However, his graduate students used counter controlled cloud chambers to make significant advances in electronic instrumentation for the detection and analysis of cosmic rays. Specifically, in 1954, John Linsley used a cloud chamber triggered by a cherenkov detector to study the charge distribution of heavy nuclei, and in 1955, Frank McDonald used one triggered by a scintillation counter for a similar purpose.
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Also known as luminophors, these compounds absorb the scintillation of the base and then emit at larger wavelength, effectively converting the ultraviolet radiation of the base into the more easily transferred visible light. Further increasing the attenuation length can be accomplished through the addition of a second fluor, referred to as a spectrum shifter or converter, often resulting in the emission of blue or green light. Common fluors include polyphenyl hydrocarbons, oxazole and oxadiazole aryls, especially, n-terphenyl (PPP), 2,5-diphenyloxazole (PPO), 1,4-di-(5-phenyl-2-oxazolyl)-benzene (POPOP), 2-phenyl-5-(4-biphenylyl)-1,3,4-oxadiazole (PBD), and 2-(4’-tert- butylphenyl)-5-(4’’-biphenylyl)-1,3,4-oxadiazole (B-PBD).
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Chart on which Jocelyn Bell Burnell first recognised evidence of a pulsar, later designated PSR B1919+21 (exhibited at Cambridge University Library) The Interplanetary Scintillation Array (also known as the IPS Array or Pulsar Array) is a radio telescope that was built in 1967 at the Mullard Radio Astronomy Observatory, in Cambridge, United Kingdom, and was operated by the Cavendish Astrophysics Group. The instrument originally covered 4 acres (16,000 m²). It was enlarged to 9 acres in 1978, and was refurbished in 1989. The array operates at a radio frequency of 81.5 MHz (3.7 m wavelength), and is made up of 4,096 dipole antennas in a phased array.
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Regional organ blood flow has been traditionally assessed by the injection of radiolabelled polyethylene microspheres into the arterial circulation of animals, of a size that they become entrapped within the microcirculation of organs. The organ to be assessed is then divided into equal-sized cubes and the amount of radiolabel within each cube is evaluated by liquid scintillation counting and recorded. The amount of radioactivity within each cube is taken to reflect the blood flow through that sample at the time of injection. It is possible to evaluate adjacent cubes from an organ in order to additively determine the blood flow through larger regions.
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Alternatively, the autoradiograph is also available as a digital image (digital autoradiography), due to the recent development of scintillation gas detectors or rare earth phosphorimaging systems.Encyclopedia of Life Sciences: Phosphorimager The film or emulsion is apposed to the labeled tissue section to obtain the autoradiograph (also called an autoradiogram). The auto- prefix indicates that the radioactive substance is within the sample, as distinguished from the case of historadiography or microradiography, in which the sample is marked using an external source. Some autoradiographs can be examined microscopically for localization of silver grains (such as on the interiors or exteriors of cells or organelles) in which the process is termed micro-autoradiography.
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It has been shown to be valuable for diagnostic inhalation studies for the evaluation of pulmonary function; for imaging the lungs; and may also be used to assess rCBF. Detection of this gas occurs via a gamma camera—which is a scintillation detector consisting of a collimator, a NaI crystal, and a set of photomultiplier tubes. By rotating the gamma camera around the patient, a three-dimensional image of the distribution of the radiotracer can be obtained by employing filtered back projection or other tomographic techniques. The radioisotopes used in SPECT have relatively long half lives (a few hours to a few days) making them easy to produce and relatively cheap.
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The DAMA/LIBRA experiment is a particle detector experiment designed to detect dark matter using the direct detection approach, by using a matrix of NaI(Tl) scintillation detectors to detect dark matter particles in the galactic halo. The experiment aims to find an annual modulation of the number of detection events, caused by the variation of the velocity of the detector relative to the dark matter halo as the Earth orbits the Sun. It is located underground at the Laboratori Nazionali del Gran Sasso in Italy. It is a follow-on to the DAMA/NaI experiment which observed an annual modulation signature over 7 annual cycles (1995-2002).
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Sir Samuel Crowe Curran (23 May 1912 – 25 February 1998), FRS, FRSE DL LLD, was a physicist and the first Principal and Vice-Chancellor of the University of Strathclyde – the first of the new technical universities in Britain. He is the inventor of the scintillation counter, the proportional counter, and the proximity fuze. Colleagues generally referred to him simply as Sam Curran and latterly just as Sir Sam. To date, Curran remains the longest serving Principal and Vice Chancellor of the University of Strathclyde, holding the post for 16 years, not counting his previous 5 years as Principal of the Royal College of Science and Technology.
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Since liquid argon is a scintillating material a particle interacting with it produces light in proportion to the energy deposited from the incident particle, this is a linear effect for low energies before quenching becomes a major contributing factor. The interaction of a particle with the argon causes ionization and recoiling along the path of interaction. The recoiling argon nuclei undergo recombination or self-trapping, ultimately resulting in the emission of 128nm vacuum ultra-violet (VUV) photons. Additionally liquid argon has the unique property of being transparent to its own scintillation light, this allows for light yields of 10's of thousands of photons produced for every MeV of energy deposited.
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The Chicago Air Shower Array (CASA) was a very large array of scintillation detectors located at Dugway Proving Grounds in Utah, USA, approximately 80 kilometers southwest of Salt Lake City. The full CASA detector, consisting of 1089 detectors began operating in 1992 in conjunction with a second instrument, the Michigan Muon Array (MIA), under the name CASA-MIA. MIA was made of 2500 square meters of buried muon detectors. At the time of its operation in the 1990s, CASA-MIA was the most sensitive experiment built to date in the study of gamma ray and cosmic ray interactions at energies above 100 TeV (1014 electronvolts).
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Antony Hewish's Interplanetary Scintillation Array). LOFAR combines aspects of many of these earlier telescopes; in particular, it uses omnidirectional dipole antennas as elements of a phased array at individual stations, and combines those phased arrays using the aperture synthesis technique developed in the 1950s. Like the earlier Cambridge Low Frequency Synthesis Telescope (CLFST) low-frequency radio telescope, the design of LOFAR has concentrated on the use of large numbers of relatively cheap antennas without any moving parts, concentrated in stations, with the mapping performed using aperture synthesis software. The direction of observation ("beam") of the stations is chosen electronically by phase delays between the antennas.
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A number of investigations have been performed to observe the gamma-ray spectra of the Sun and other astronomical sources, both galactic and extra-galactic. The Gamma-Ray Imaging Spectrometer, the Hard X-ray/Low-Energy Gamma-ray experiment (A-4) on HEAO 1, the Burst and Transient Spectrometry Experiment (BATSE) and the OSSI (Oriented Scintillation Spectrometer Experiment) on CGRO, the C1 germanium (Ge) gamma-ray instrument on HEAO 3, and the Ge gamma-ray spectrometer (SPI) on the ESA INTEGRAL mission are examples of cosmic spectrometers, while the GRS on the SMM and the imaging Ge spectrometer on the RHESSI satellite have been devoted to solar observations.
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Some constructions of scintillation counters can be used as gamma-ray spectrometers. The gamma photon energy is discerned from the intensity of the flash of the scintillator, a number of low-energy photons produced by the single high-energy one. Another approach relies on using Germanium detectors - a crystal of hyperpure germanium that produces pulses proportional to the captured photon energy; while more sensitive, it has to be cooled to a low temperature, requiring a bulky cryogenic apparatus. Handheld and many laboratory gamma spectrometers are therefore the scintillator kind, mostly with thallium-doped sodium iodide, thallium-doped caesium iodide, or, more recently, cerium doped lanthanum bromide.
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Automated airport weather stations use a light emitting diode weather identifier (LEDWI) to determine if and what type of precipitation is falling. The LEDWI sensor measures the scintillation pattern of the precipitation falling through the sensor's infrared beam (approximately 50 millimeters in diameter) and determines from a pattern analysis of the particle size and fall velocity whether the precipitation is rain or snow. If precipitation is determined to be falling, but the pattern is not conclusively identified as either rain or snow, unknown precipitation is reported. Automated airport weather stations are not yet able to report hail, ice pellets, and various other intermediate forms of precipitation.
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The total thickness of a calorimeter was about 175 cm so as to fully absorb the showers of the most energetic particles from a collision. The stainless steel vessels needed to contain the modules at liquid argon temperature (-190 C) were relatively thick, so scintillation detectors were inserted between central and end calorimeters to correct for energy lost in the cryostat walls. A primary task for the calorimetry is identification of jets, the sprays of particles created as quarks and gluons escape from their collision point. Jet identification and measurement of their directions and energies allow analyses to recreate the momenta of the underlying quarks and gluons in the primary collision.
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Charge and/or scintillation light produced in this way can be collected to produce a detected signal. A major challenge in fast neutron detection is discerning such signals from erroneous signals produced by gamma radiation in the same detector. Methods such as pulse shape discrimination can be used in distinguishing neutron signals from gamma-ray signals, although certain inorganic scintillator-based detectors have been developed to selectively detect neutrons in mixed radiation fields inherently without any additional techniques. Fast neutron detectors have the advantage of not requiring a moderator, and are therefore capable of measuring the neutron's energy, time of arrival, and in certain cases direction of incidence.
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In 1956, McDonald began his career at the University of Iowa. In collaboration with James A. Van Allen he worked on "rockoons", which were small rockets lifted to 70,000 feet by balloons. At this height, the rockets would ignite and shoot up to 350,000 feet, carrying equipment intended to study cosmic rays and particles trapped in Earth's magnetic field. The same year, McDonald combined the scintillation counter of his thesis with a cherenkov detector into a balloon instrument that not only provided a novel measurement of the energy spectrum of primary cosmic ray helium nuclei, but also served as a prototype for devices carried on many spacecraft.
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A neutron camera is an imaging system based on a digital camera or similar detector array. Neutrons pass through the object to be imaged, then a scintillation screen converts the neutrons into visible light. This light then pass through some optics (intended to minimize the camera's exposure to ionizing radiation), then the image is captured by the CCD camera (several other camera types also exist, including CMOS and CID, producing similar results). Neutron cameras allow real time images (generally with low resolution), which has proved useful for studying two phase fluid flow in opaque pipes, hydrogen bubble formation in fuel cells, and lubricant movement in engines.
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Sketch of the working principle of a xenon dual-phase TPC The XENON experiment operates a dual phase time projection chamber (TPC), which utilizes a liquid xenon target with a gaseous phase on top. Two arrays of photomultiplier tubes (PMTs), one at the top of the detector in the gaseous phase (GXe), and one at the bottom of the liquid layer (LXe), detect scintillation and electroluminescence light produced when charged particles interact in the detector. Electric fields are applied across both the liquid and gaseous phase of the detector. The electric field in the gaseous phase has to be sufficiently large to extract electrons from the liquid phase.
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Slotin, who was leaving Los Alamos, was showing the technique to Alvin C. Graves, who would use it in a final test before the Operation Crossroads nuclear tests scheduled a month later at Bikini Atoll. It required the operator to place two half-spheres of beryllium (a neutron reflector) around the core to be tested and manually lower the top reflector over the core using a thumb hole on the top. As the reflectors were manually moved closer and farther away from each other, scintillation counters measured the relative activity from the core. The experimenter needed to maintain a slight separation between the reflector halves in order to stay below criticality.
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Tritium (Hydrogen-3) is a very low beta energy emitter that can be used to label proteins, nucleic acids, drugs and almost any organic biomolecule. The maximum theoretical specific activity of tritium is 28.8 Ci/mmol (1.066 PBq/mol). However, there is often more than one tritium atom per molecule: for example, tritiated UTP is sold by most suppliers with carbons 5 and 6 each bonded to a tritium atom. For tritium detection, liquid scintillation counters have been classically employed, in which the energy of a tritium decay is transferred to a scintillant molecule in solution which in turn gives off photons whose intensity and spectrum can be measured by a photomultiplier array.
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Iodine-125 is commonly used for labeling proteins, usually at tyrosine residues. Unbound iodine is volatile and must be handled in a fume hood. Its maximum specific activity is 2,176 Ci/mmol (80.51 PBq/mol). A good example of the difference in energy of the various radionuclei is the detection window ranges used to detect them, which are generally proportional to the energy of the emission, but vary from machine to machine: in a Perkin elmer TriLux Beta scintillation counter , the H-3 energy range window is between channel 5–360; C-14, S-35 and P-33 are in the window of 361–660; and P-32 is in the window of 661–1024.
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Of all the well data sets recorded and collected, well logs are the most valuable as they are vital for reservoir and formation evaluation. Wireline (well) logs are then combined with drilling data, mud logs, and measurements while drilling (MWD) and coring information in order to choose correct testing and completion intervals to properly evaluate the production potential of the well. There are two categories of well log data: the original data (e.g. Gamma Ray log as a result of gamma rays measurements in the borehole, through an iodine crystal scintillation detector, calibrated as per normal field operational procedure) or derived data (data resulting from the processing of the original data, e. g.
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Liquid scintillation counter Samples are dissolved or suspended in a "cocktail" containing a solvent (historically aromatic organics such as xylene or toluene, but more recently less hazardous solvents are used), typically some form of a surfactant, and small amounts of other additives known as "fluors" or scintillators. Scintillators can be divided into primary and secondary phosphors, differing in their luminescence properties. Beta particles emitted from the isotopic sample transfer energy to the solvent molecules: the π cloud of the aromatic ring absorbs the energy of the emitted particle. The energized solvent molecules typically transfer the captured energy back and forth with other solvent molecules until the energy is finally transferred to a primary scintillator.
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Instruments aboard the spacecraft included a Lyman-alpha telescope, a rubidium-vapor magnetometer, electrostatic analyzers, medium-energy range particle detectors, two triple coincidence telescopes, a cosmic-ray integrating ionization chamber, cosmic dust detectors, and solar X-ray scintillation counters. There was no camera or midcourse correction engine on the Block I spacecraft. The communications system included the high-gain antenna and an omnidirectional medium-gain antenna and two transmitters, one at 960.1 MHz with 0.25 watts power output and the other at 960.05 MHz with 3 watts power output. Power was to be furnished by 8680 solar cells on the two panels, a silver-zinc battery, and smaller batteries on some of the experiments.
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The objective of the UA4 experiment was to measure the antiproton-proton cross-section, in order to show that cross-sections rising with energy are true a characteristic of strong interaction. One had previously measured proton-antiproton cross-sections at the Intersecting Storage Rings, but as the Proton-Antiproton Collider — a modification of the Super Proton Synchrotron — began operating, the measurements could be done in a new energy range: up to 540 GeV center-of-mass energy. Elastic events were detected by high resolution wire chambers and scintillation-counter hodoscopes. A system of drift chamber telescopes and counter telescopes were placed on the left and the right side of the crossing region to detect inelastic events.
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Scintillation counters are usually not ideal for the detection of heavy ions for three reasons: # the very high ionizing power of heavy ions induces quenching effects which result in a reduced light output (e.g. for equal energies, a proton will produce 1/4 to 1/2 the light of an electron, while alphas will produce only about 1/10 the light); # the high stopping power of the particles also results in a reduction of the fast component relative to the slow component, increasing detector dead-time; # strong non-linearities are observed in the detector response especially at lower energies. The reduction in light output is stronger for organics than for inorganic crystals. Therefore, where needed, inorganic crystals, e.g.
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Computer representation of false-color image of a cross section of human brain, based on scintillography in Positron-Emission Tomography Scintillography is an imaging method of nuclear events provoked by collisions or charged current interactions among nuclear particles or ionizing radiation and atoms which result in a brief, localised pulse of electromagnetic radiation, usually in the visible light range (Cherenkov radiation). This pulse (scintillation) is usually detected and amplified by a photomultiplier or charged coupled device elements, and its resulting electrical waveform is processed by computers to provide two- and three-dimensional images of a subject or region of interest. Schematic of a photomultiplier tube coupled to a scintillator. Cross section of a gamma camera.
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The original particle arrives with high energy and hence a velocity near the speed of light, so the products of the collisions tend also to move generally in the same direction as the primary, while to some extent spreading sidewise. In addition, the secondary particles produce a widespread flash of light in forward direction due to the Cherenkov effect, as well as fluorescence light that is emitted isotropically from the excitation of nitrogen molecules. The particle cascade and the light produced in the atmosphere can be detected with surface detector arrays and optical telescopes. Surface detectors typically use Cherenkov detectors or Scintillation counters to detect the charged secondary particles at ground level.
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At that time, the 85-2 telescope was placed at the end of the track and cables were connected between the two telescopes. The GBI began operation that year as a two element interferometer in order to test large aperture synthesis arrays and study radio astrometry and interstellar scintillation. 85-3 movable telescope with truck tires to allow it to move along the track In 1967 the array was upgraded with construction of the third element (85-3) to be located in the middle of the track. Both 85-2 and 85-3 had truck tires mounted on either side to allow them to be moved along the track to test different baselines.
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Fluorescent materials are used in applications in which the phosphor is excited continuously: cathode ray tubes (CRT) and plasma video display screens, fluoroscope screens, fluorescent lights, scintillation sensors, and white LEDs, and luminous paints for black light art. Phosphorescent materials are used where a persistent light is needed, such as glow-in-the-dark watch faces and aircraft instruments, and in radar screens to allow the target 'blips' to remain visible as the radar beam rotates. CRT phosphors were standardized beginning around World War II and designated by the letter "P" followed by a number. Phosphorus, the light- emitting chemical element for which phosphors are named, emits light due to chemiluminescence, not phosphorescence.
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Figure 1: The experimental setup Figure 1 shows the typical main components of the setup of a neutron detection unit. In principle, the diagram shows the setup as it would be in any modern particle physics lab, but the specifics describe the setup in Jefferson Lab (Newport News, Virginia). In this setup, the incoming particles, comprising neutrons and photons, strike the neutron detector; this is typically a scintillation detector consisting of scintillating material, a waveguide, and a photomultiplier tube (PMT), and will be connected to a data acquisition (DAQ) system to register detection details. The detection signal from the neutron detector is connected to the scaler unit, gated delay unit, trigger unit and the oscilloscope.
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In 1946 he returned to Cambridge to be based at the Cambridge Observatory as Senior Observer and was able to complete the observational work on his PhD In 1947 he transferred to Dunsink Observatory in Ireland where he stayed until 1953. At Dunsink he produced a number of papers concerning the photoelectric recording of stellar occultations and stellar scintillation , topics that led ultimately to the technologies that support the discovery of exoplanets and the construction of large ground-based optical telescopes respectively. He was also intensely practical and gained a significant reputation for the design and implementation of novel instruments. At Dunsink these skills were put to good effect in building it up as a modern observatory.
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These experiments began after Rutherford had noticed that, when alpha particles were shot into air (mostly nitrogen), his scintillation detectors showed the signatures of typical hydrogen nuclei as a product. After experimentation Rutherford traced the reaction to the nitrogen in air and found that when alpha particles were introduced into pure nitrogen gas, the effect was larger. In 1919 Rutherford assumed that the alpha particle knocked a proton out of nitrogen, turning it into carbon. After observing Blackett's cloud chamber images in 1925, Rutherford realized that the opposite was the case: after capture of the alpha particle, a proton is ejected, so that heavy oxygen, not carbon, is the end result i.e.
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Distinguishing between gamma- rays of slightly different energy is an important consideration in the analysis of complex spectra, and the ability of a GRS to do so is characterized by the instrument's spectral resolution, or the accuracy with which the energy of each photon is measured. Semi-conductor detectors, based on cooled germanium or silicon detecting elements, have been invaluable for such applications. Because the energy level spectrum of nuclei typically dies out above about 10 MeV, gamma-ray instruments looking to still higher energies generally observe only continuum spectra, so that the moderate spectral resolution of scintillation (often sodium iodide (NaI) or caesium iodide, (CsI) spectrometers), often suffices for such applications.
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A Large Aperture Scintillometer (transmitter) for measurement of the sensible heat flux over long distances at Wageningen University measurement site A scintillometer is a scientific device used to measure small fluctuations of the refractive index of air caused by variations in temperature, humidity, and pressure. It consists of an optical or radio wave transmitter and a receiver at opposite ends of an atmospheric propagation path. The receiver detects and evaluates the intensity fluctuations of the transmitted signal, called scintillation. The magnitude of the refractive index fluctuations is usually measured in terms of C_n^2, the structure constant of refractive index fluctuations, which is the spectral amplitude of refractive index fluctuations in the inertial subrange of turbulence.
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One also gathered information about the momentum (a quantity related to mass and energy) of the particles by measuring their deflection in the magnetic field present in the detector. The three main outer layers were the electro-magnetic calorimeter (also called BGO because it's made of Bismuth Germanium Oxide), the hadronic calorimeter (HCAL) and the muon detector. Calorimeters are dense and stop most particles, measuring their energy. A set of scintillation counters was placed between the electro-magnetic and hadronic calorimeters: one of their functions was to help in recognising and rejecting signals coming from cosmic ray muons, very highly energetic particles which come from the space and can disturb the measurement.
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The individual holes limit photons which can be detected by the crystal to a cone; the point of the cone is at the midline center of any given hole and extends from the collimator surface outward. However, the collimator is also one of the sources of blurring within the image; lead does not totally attenuate incident gamma photons, there can be some crosstalk between holes. Unlike a lens, as used in visible light cameras, the collimator attenuates most (>99%) of incident photons and thus greatly limits the sensitivity of the camera system. Large amounts of radiation must be present so as to provide enough exposure for the camera system to detect sufficient scintillation dots to form a picture.
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As a result, Wyatt Technology developed the first in its line of DAWN (originally an acronym for “Dual Angle Weighted Nephelometry”) multiangle light scattering instruments. Continuing interest in the DAWN instruments as well as Small Business Innovation Research (SBIR) contracts involving the rapid detection of contaminants in water and air spurred the growth of the company which was incorporated as Wyatt Technology Corporation in 1984. Wyatt proceeded to develop batch light scattering instruments (DAWN-B) that made measurements from samples contained within scintillation vials as well as flow through instruments (DAWN-F) for use in conjunction with high performance liquid chromatography (HPLC). In the late 1980s Wyatt purchased the Optilab line of interferometric refractometers from the Swedish company Tekator.
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Widespread clinical use of nuclear medicine began in the early 1950s, as knowledge expanded about radionuclides, detection of radioactivity, and using certain radionuclides to trace biochemical processes. Pioneering works by Benedict Cassen in developing the first rectilinear scanner and Hal O. Anger's scintillation camera (Anger camera) broadened the young discipline of nuclear medicine into a full-fledged medical imaging specialty. By the early 1960s, in southern Scandinavia, Niels A. Lassen, David H. Ingvar, and Erik Skinhøj developed techniques that provided the first blood flow maps of the brain, which initially involved xenon-133 inhalation; an intra-arterial equivalent was developed soon after, enabling measurement of the local distribution of cerebral activity for patients with neuropsychiatric disorders such as schizophrenia.
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Because of the scope of this mission, several unique challenges need to be addressed in implementing hardware. Typical low Earth orbit (LEO) CubeSats can use "off-the-shelf" hardware, or parts available commercially for other uses, but because LunaH-Map is intended to run longer and travel further than most LEO CubSat missions, commercial parts cannot be expected to perform reliably for the mission duration unmodified. Also, unlike most conventional CubeSats, LunaH-Map will need to navigate to its desired orbit after leaving the launch vehicle, so it will need to be equipped with its own propulsion system. The primary science instrument will be a scintillation neutron detector composed of elpasolite (Cs2YLiCl6:Ce or CLYC).
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The Washington Area Large-scale Time-coincidence Array (WALTA) is a cosmic ray physics experiment run by the University of Washington to investigate ultra high energy cosmic rays (>1019eV). The program uses detectors placed at Seattle-area high schools and colleges which are linked via the internet, effectively forming an Extensive Air Shower array. In addition to working on the unexplained levels of Ultra High Energy cosmic ray (UHECR) flux, it hopes to serve as a pedagogical tool for increasing the physics involvement of high schools and community colleges with a University level physics experiment. Each site has three to four scintillation detectors with the goal of having enough sites to cover a 200 km2 area around the city of Seattle.
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Intensity against alpha energy for four isotopes, note that the line width is narrow and the fine details can be seen Intensity against alpha energy for four isotopes, note that the line width is wide and some of the fine details can not be seen. This is for liquid scintillation counting, where random effects cause a variation in the number of visible photons generated per alpha decay From left to right the peaks are due to 209Po, 210Po, 239Pu and 241Am. The fact that isotopes such as 239Pu and 241Am have more than one alpha line indicates that the nucleus has the ability to be in different discrete energy levels. Calibration: MCA does not work on energy, it works on voltage.
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Drawing from techniques learned during the polishing of the Centenary and the Golden Jubilee diamonds, and from his experience with the "Flower Cuts", Gabi created the Gabrielle Diamonds, the world's first triple brilliant cut diamond. The Gabrielle Diamond in the Round shape consists of 105 facets, 48 facets more than the Classic Round Brilliant cut (with additional 8 crown facets and 40 pavilion facets). The Gabrielle Diamond was shown by a Light Study to exhibit 200% more scintillation than an excellent-cut classic brilliant diamond, and at the same time exhibited significantly greater brilliance and fire.Light Study done in the US This was achieved by increasing the path of light through the diamond, so that the diamond appeares to sparkle from all angles.
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The Liquid Scintillator Neutrino Detector (LSND) was a scintillation counter at Los Alamos National Laboratory that measured the number of neutrinos being produced by an accelerator neutrino source. The LSND project was created to look for evidence of neutrino oscillation, and its results conflict with the standard model expectation of only three neutrino flavors, when considered in the context of other solar and atmospheric neutrino oscillation experiments. Cosmological data bound the mass of the sterile neutrino to ms < 0.26eV (0.44eV) at 95% (99.9%) confidence limit, excluding at high significance the sterile neutrino hypothesis as an explanation of the LSND anomaly. The controversial LSND result was tested by the MiniBooNE experiment at Fermilab, which refuted a simple 2-neutrino oscillation interpretation of the LSND result.
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The Third Orbiting Solar Observatory, OSO 3, carried a hard X-ray experiment (7.7 to 210 keV) and an MIT gamma-ray instrument (>50 MeV), besides a complement of solar physics instruments. The third Orbiting Solar Observatory (OSO 3) was launched on March 8, 1967, into a nearly circular orbit of mean altitude 550 km, inclined at 33° to the equatorial plane, deactivated on June 28, 1968, followed by reentry on April 4, 1982. Its XRT consisted of a continuously spinning wheel (1.7 s period) in which the hard X-ray experiment was mounted with a radial view. The XRT assembly was a single thin NaI(Tl) scintillation crystal plus phototube enclosed in a howitzer-shaped CsI(Tl) anti-coincidence shield.
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AGILE's instrumentation includes a Gamma Ray Imaging Detector (GRID) sensitive in the 30 MeV – 50 GeV energy range, a SuperAGILE (SA) hard X-ray monitor sensitive in the 18–60 keV energy range, a Mini-Calorimeter (MCAL) non-imaging gamma-ray scintillation detector sensitive in the 350 keV – 100 MeV energy range,Scientific Goals and Instrument Performance of the Gamma-Ray Imaging Detector AGILE and an Anti-coincidence System (AC), based on a plastic scintillator, to assist with suppressing unwanted background events. The SuperAGILE SA is an instrument based on a set of four silicon strip detectors, each equipped with one-dimensional coded mask. The SA is designed to detect X-Ray signals from known sources and burst-like signals. It provides long-term monitoring of flux and spectral features.
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Because solid scintillating material was unavailable, they decided to use terphenyl dissolved in benzine, which is an efficient liquid scintillator. With the aid of three counters deployed on the roof of the MIT Physics building during the winter of 1952/53, they found that shower particles arrived within only one or two meters of a disk, which travels at nearly the speed of light in the direction of the shower axis. This result showed that scintillation counters can not only determine of the arrival times of shower disks at many detectors spread over a large area, but also to estimate the number of particles striking each detector. These capabilities combine the "fast-timing" method of determining shower arrival directions with the density sampling method of determining their size and the location of their axes.
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Described as a "very refined" artist by the critics (La Presse, Montreal), the young Québec harpist Valérie Milot has a flawless technique and a style that is both colourful and powerful, thus challenging the clichés one associates with the instrument. After the jury unanimously awarded her the ‘'Prize of Great Distinction'’ and the Wilfred-Pelletier bursary when she finished her studies at the Conservatoire de musique de Trois-Rivières with Caroline Lizotte, Milot pursued her training in New York City with the internationally renowned harpist Rita Costanzi. The winner of numerous competitions, Milot was the first harpist in nearly 100 years to receive the Prix d’Europe (2008). In 2005, she was a laureate at the American Harp Society National Competition, where she won the "Salzedo Centennial Fund" award for her interpretation of Carlos Salzedo's Scintillation.
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This is comparatively (on the order of 1000 times) shorter than the time taken by the freed electrons to drift to the wire planes, so it is often sufficient to demarcate the collection time of scintillation photons as a trigger time (t0) for an event. With this trigger time, one can then find electron drift times, which enables three-dimensional reconstruction of an event. While such systems are not the only means by which a LArTPC can identify a trigger time, they are necessary for studying phenomena like supernovae and proton decay, where the particles undergoing decay or interaction are not produced in a human-made accelerator and the timing of a beam of particles is therefore not known. Photomultiplier tubes, light guides, and silicon photomultipliers are examples of instruments used to collect this light.
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The practical choice of a scintillator material is usually a compromise among those properties to best fit a given application. Among the properties listed above, the light output is the most important, as it affects both the efficiency and the resolution of the detector (the efficiency is the ratio of detected particles to the total number of particles impinging upon the detector; the energy resolution is the ratio of the full width at half maximum of a given energy peak to the peak position, usually expressed in %). The light output is a strong function of the type of incident particle or photon and of its energy, which therefore strongly influences the type of scintillation material to be used for a particular application. The presence of quenching effects results in reduced light output (i.e.
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Measurements of the energy and arrival directions of the ultra-high-energy primary cosmic rays by the techniques of density sampling and fast timing of extensive air showers were first carried out in 1954 by members of the Rossi Cosmic Ray Group at the Massachusetts Institute of Technology. The experiment employed eleven scintillation detectors arranged within a circle 460 metres in diameter on the grounds of the Agassiz Station of the Harvard College Observatory. From that work, and from many other experiments carried out all over the world, the energy spectrum of the primary cosmic rays is now known to extend beyond 1020 eV. A huge air shower experiment called the Auger Project is currently operated at a site on the pampas of Argentina by an international consortium of physicists.
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Antineutrinos with an energy above the threshold of caused charged current interactions with the protons in the water, producing positrons and neutrons. This is very much like decay, where energy is used to convert a proton into a neutron, a positron () and an electron neutrino () is emitted: From known decay: : Energy + → + + In the Cowan and Reines experiment, instead of an outgoing neutrino, you have an incoming antineutrino () from a nuclear reactor: : Energy (>) + + → + The resulting positron annihilation with electrons in the detector material created photons with an energy of about . Pairs of photons in coincidence could be detected by the two scintillation detectors above and below the target. The neutrons were captured by cadmium nuclei resulting in gamma rays of about that were detected a few microseconds after the photons from a positron annihilation event.
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Direct detection experiments aim to observe low-energy recoils (typically a few keVs) of nuclei induced by interactions with particles of dark matter, which (in theory) are passing through the Earth. After such a recoil the nucleus will emit energy in the form of scintillation light or phonons, as they pass through sensitive detection apparatus. To do this effectively, it is crucial to maintain a low background, and so such experiments operate deep underground to reduce the interference from cosmic rays. Examples of underground laboratories with direct detection experiments include the Stawell mine, the Soudan mine, the SNOLAB underground laboratory at Sudbury, the Gran Sasso National Laboratory, the Canfranc Underground Laboratory, the Boulby Underground Laboratory, the Deep Underground Science and Engineering Laboratory and the China Jinping Underground Laboratory.
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ReActive Transport (RAT) has been developed to solve reactive transport problems in subsurface porous media that involves highly nonlinearly coupled physical processes of fluid flow, solute transport, biogeochemical reactions and media-solution interactions. These problems are common in various subsurface-engineered systems, such as engineered environmental remediation, enhanced geothermal systems and carbon dioxide geological sequestration. Currently, the physics that could be coupled in RAT include: single-phase fluid flow in porous media, advection, dispersion and diffusion transport, aqueous kinetic reaction, aqueous equilibrium reaction, kinetic mineral precipitation/dissolution reaction, and Carmen-Kozeny porosity-permeability relationship. This software is not to be confused with the Reactor Analysis Tool (RAT) which is a toolkit based on ROOT and GEANT4 for microphysical simulations of scintillation detectors used in neutrino and dark matter experiments including Braidwood, SNO+, and DEAP-3600.
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It performs key quasar-based reference frame operations, transit detections of exoplanets, Vilnius photometry, M-Dwarf star analysis, dynamical system analysis, reference support to orbiting space object information, horizontal parallax guide support to NPOI, and it performs photometric operations support to astrometric studies (along with its newer siblings). The 40-inch telescope can carry a number of liquid nitrogen-cooled cameras, a coronagraph, and a nine-stellar magnitude neutral density spot focal plane array camera, through which star positions are cross-checked before use in fundamental NPOI reference frame astrometry. This telescope is also used to test internally developed optical adaptive optics (AO) systems, using tip-tilt and deformable mirror optics. The Shack–Hartmann AO system allows for corrections of the wavefront's aberrations caused by scintillation (degraded seeing), to higher Zernike polynomials.
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Within the Solar System, space weather is influenced by the solar wind and the interplanetary magnetic field (IMF) carried by the solar wind plasma. A variety of physical phenomena are associated with space weather, including geomagnetic storms and substorms, energization of the Van Allen radiation belts, ionospheric disturbances and scintillation of satellite-to-ground radio signals and long-range radar signals, aurora, and geomagnetically induced currents at Earth's surface. Coronal mass ejections (CMEs), their associated shock waves and coronal clouds are also important drivers of space weather as they can compress the magnetosphere and trigger geomagnetic storms. Solar energetic particles (SEP) accelerated by coronal mass ejections or solar flares can trigger solar particle events (SPEs), a critical driver of human impact space weather as they can damage electronics onboard spacecraft (e.g.
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Kenneth John Frost (October 3, 1934 – August 5, 2013)Kenneth J. Frost (1934 - 2013) was a pioneer in the early space program, designing and flying instruments to detect and measure X-rays and gamma-rays in space, primarily from the Sun. He was the first to suggest the use of an active scintillation shield operated in electronic anticoincidence with the primary detector to reduce the background from cosmic ray interactions, an innovation that made sensitive hard X-ray and gamma-ray astronomy possible. He was an American astrophysicist at Goddard Space Flight Center working as a civil servant for the National Aeronautics and Space Administration. During his career, he was the project scientist of the Solar Maximum Mission, principal investigator of six science instruments, the head of the Solar Physics Branch, and the Associate Director of Space Sciences.
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A technique for identifying these non-dark matter events is pulse shape discrimination (PSD), which characterizes an event based on the timing signature of the scintillation light from liquid argon. PSD is possible in a liquid argon detector because interactions due to different incident particles such as electrons, high energy photons, alphas, and neutrons create different proportions of excited states of the recoiling argon nuclei, these are known as singlet and triplet states and they decay with characteristic lifetimes of 6 ns and 1300 ns respectively. Interactions from gammas and electrons produce primarily triplet excited states through electronic recoils, while neutron and alpha interactions produce primarily singlet excited states through nuclear recoils. It is expected that WIMP-nucleon interactions also produce a nuclear recoil type signal due to the elastic scattering of the dark matter particle with the argon nucleus.
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NEVOD building NEVOD (, Neutrino Water Detector; nevod means "dragnet" in Russian) is a neutrino detector and cosmic ray experiment that attempts to detect Cherenkov radiation arising from interactions between water and charged particles (mostly muons). It represents the first attempt to perform such measurements at the Earth's surface; it is because of this surface deployment that the experiment is also able to investigate cosmic rays. NEVOD is situated at the Moscow Engineering Physics Institute (MEPhI). The term NEVOD experimental complex is used of the experimental complex built around the original water Cherenkov detector for the study of cosmic rays; as of 2018, the experimental complex consists of: the Cherenkov water detector (the eponymous NEVOD detector), a coordinate-tracking detector DECOR, an array of scintillation detectors forming the calibration telescopes system CTS, and PRISMA array of thermal neutron detectors.
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In 2002 Dwyer, along with colleagues from Florida Institute of Technology and the University of Florida, launched rockets during thunderstorms at a facility now known as the UF/Florida Tech International Center for Lightning Research and Testing (ICLRT) at Camp Blanding, Florida. Using a heavily shielded instrument containing a scintillation detector, built by Dwyer and his students, they found that lightning does indeed produce x-rays and that x-ray emission is common for lightning. This research was published in Science (Dwyer et al. 2003). Since that time, Dwyer and his collaborators have established many key properties of the x-ray emissions from lightning, including the fact that the x-ray emission is produced during the lightning stepping process, has energies up to approximately 1 MeV and the x-rays are produced in the high field regions generated by the leader as it propagates.
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Elektron 2 and 4 had design masses of , were in diameter and long, also cylindrical, but with a skirt of solar cells with a combined area of 20 m2 for power generation rather than solar panels. The satellites were to be boosted into highly eccentric × orbits to map the outer Van Allen belt while, simultaneously, Elektron 1 and 3 probed the inner radiation belt. To achieve this orbit, Elektron 2 and 4 were each equipped with solid-propellant perigee kick motor of 3,350 kgf and 12 to 15 seconds duration. The experiment packages for Elektron 2 and 4 were also identical and each included a radio frequency mass spectrometer; Geiger counters, scintillation counters, and semiconductor detectors for radiation studies; a spherical ion trap; two three-axis fluxgate magnetometers; a galactic radio-noise receiver; solar X-ray photometers; and a Cerenkov-scintillator cosmic-ray telescope.
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The HEAO "C-1" instrument (as it was known before launch) was a sky-survey experiment, operating in the hard X-ray and low- energy gamma-ray bands. The gamma-ray spectrometer was especially designed to search for the 511 keV gamma-ray line produced by the annihilation of positrons in stars, galaxies, and the interstellar medium (ISM), nuclear gamma-ray line emission expected from the interactions of cosmic rays in the ISM, the radioactive products of cosmic nucleosynthesis, and nuclear reactions due to low-energy cosmic rays. In addition, careful study was made of the spectral and time variations of known hard X-ray sources. The experimental package contained four cooled, p-type high-purity Ge gamma-ray detectors with a total volume of about 100 cm^3, enclosed in a thick (6.6 cm average) caesium iodide (CsI) scintillation shield in active anti-coincidenceL.
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There are several older modified brilliant cuts of uncertain age that, while no longer widely used, are notable for history's sake. They are all round in outline and modify the standard round brilliant by adding facets and changing symmetry, either by dividing the standard facets or by placing new ones in different arrangements. These cuts include: the King and Magna cuts, both developed by New York City firms, with the former possessing 86 facets and 12-fold symmetry and the latter with 102 facets and 10-fold symmetry; the High-Light cut, developed by Belgian cutter M. Westreich, with 16 additional facets divided equally between the crown and pavilion; and the Princess 144, introduced in the 1960s, with 144 facets and 8-fold symmetry. Not to be confused with the mixed Princess cut, the Princess 144 cut makes for a lively stone with good scintillation; the extra facets are cut under the girdle rather than subdivided.
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The term "plastic scintillator" typically refers to a scintillating material in which the primary fluorescent emitter, called a fluor, is suspended in the base, a solid polymer matrix. While this combination is typically accomplished through the dissolution of the fluor prior to bulk polymerization, the fluor is sometimes associated with the polymer directly, either covalently or through coordination, as is the case with many Li6 plastic scintillators. Polyethylene naphthalate has been found to exhibit scintillation by itself without any additives and is expected to replace existing plastic scintillators due to higher performance and lower price. The advantages of plastic scintillators include fairly high light output and a relatively quick signal, with a decay time of 2–4 nanoseconds, but perhaps the biggest advantage of plastic scintillators is their ability to be shaped, through the use of molds or other means, into almost any desired form with what is often a high degree of durability.
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In the apparatuses that detect photons, the locations on its detection screen that indicate reception of the photon give an indication of whether or not it was manifesting its wave nature during its flight from photon source to the detection device. Therefore, it is commonly said that in a double-slit experiment a photon exhibits its wave nature when it passes through both of the slits and appears as a dim wash of illumination across the detection screen, and manifests its particle nature when it passes through only one slit and appears on the screen as a highly localized scintillation. Given the interpretation of quantum physics that says a photon is either in its guise as a wave or in its guise as a particle, the question arises: When does the photon decide whether it is going to travel as a wave or as a particle? Suppose that a traditional double-slit experiment is prepared so that either of the slits can be blocked.
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Chart on which Burnell first recognised evidence of a pulsar, exhibited at Cambridge University Library Composite Optical/X-ray image of the Crab Nebula, showing synchrotron emission in the surrounding pulsar wind nebula, powered by injection of magnetic fields and particles from the central pulsar She graduated from the University of Glasgow with a Bachelor of Science degree in Natural Philosophy (physics), with honours, in 1965 and obtained a PhD degree from the University of Cambridge in 1969. At Cambridge, she attended New Hall, Cambridge, and worked with Hewish and others to construct the Interplanetary Scintillation Array just outside Cambridge to study quasars, which had recently been discovered. On 28 November 1967, she detected a "bit of scruff" on her chart-recorder papers that tracked across the sky with the stars. The signal had been visible in data taken in August, but as the papers had to be checked by hand, it took her three months to find it.
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According to Bragg's law, when an X-ray beam of wavelength "λ" strikes the surface of a crystal at an angle "Θ" and the crystal has atomic lattice planes a distance "d" apart, then constructive interference will result in a beam of diffracted x-rays that will be emitted from the crystal at angle "Θ" if ::nλ = 2d sinΘ, where n is an integer. This means that a crystal with a known lattice size will deflect a beam of x-rays from a specific type of sample at a pre-determined angle. The x-ray beam can be measured by placing a detector (usually a scintillation counter or a proportional counter) in the path of the deflected beam and, since each element has a distinctive x-ray wavelength, multiple elements can be determined by having multiple crystals and multiple detectors. To improve accuracy the x-ray beams are usually collimated by parallel copper blades called a Söller collimator.
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Early experimenters in X-ray and gamma-ray astronomy found that their detectors, flown on balloons or sounding rockets, were corrupted by the large fluxes of high-energy photon and cosmic-ray charged-particle events. Gamma-rays, in particular, could be collimated by surrounding the detectors with heavy shielding materials made of lead or other such elements, but it was quickly discovered that the high fluxes of very penetrating high-energy radiation present in the near-space environment created showers of secondary particles that could not be stopped by reasonable shielding masses. To solve this problem, detectors operating above 10 or 100 keV were often surrounded by an active anticoincidence shield made of some other detector, which could be used to reject the unwanted background events.Laurence E. Peterson, Instrumental Technique in X-Ray Astronomy. Annual Review of Astronomy and Astrophysics 13, 423 (1975) Drawing of an active anticoincidence collimated scintillation spectrometer designed for gamma-ray astronomy in the energy range from 0.1 to 3 MeV.
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A more thorough description of the astronomical seeing at an observatory is given by producing a profile of the turbulence strength as a function of altitude, called a C_n^2 profile. C_n^2 profiles are generally performed when deciding on the type of adaptive optics system which will be needed at a particular telescope, or in deciding whether or not a particular location would be a good site for setting up a new astronomical observatory. Typically, several methods are used simultaneously for measuring the C_n^2 profile and then compared. Some of the most common methods include: # SCIDAR (imaging the shadow patterns in the scintillation of starlight) # LOLAS (a small-aperture variant of SCIDAR designed for low- altitude profiling) # SLODAR # MASS # MooSci (11-channel lunar scintillometer for ground level profiling) # RADAR mapping of turbulence # Balloon-borne thermometers to measure how quickly the air temperature is fluctuating with time due to turbulence # V2 Precision Data Collection Hub (PDCH) with differential temperature sensors use to measure atmospheric turbulence There are also mathematical functions describing the C_n^2 profile.
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Instruments that measure geoneutrinos are large scintillation detectors. They use the inverse beta decay reaction, a method proposed by Bruno Pontecorvo that Frederick Reines and Clyde Cowan employed in their pioneering experiments in 1950s. Inverse beta decay is a charged current weak interaction, where an electron antineutrino interacts with a proton, producing a positron and a neutron: :\bar u_e + p \rightarrow e^+ + n Only antineutrinos with energies above the kinematic threshold of 1.806 MeV—the difference between rest mass energies of neutron plus positron and proton—can participate in this interaction. After depositing its kinetic energy, the positron promptly annihilates with an electron: :e^+ + e^- \rightarrow \gamma + \gamma With a delay of few tens to few hundred microseconds the neutron combines with a proton to form a deuteron: :n + p \rightarrow d + \gamma The two light flashes associated with the positron and the neutron are coincident in time and in space, which provides a powerful method to reject single-flash (non-antineutrino) background events in the liquid scintillator.
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Despite the beam being narrow, it will eventually spread over long distances due to the divergence of the laser beam, as well as due to scintillation and beam wander effects, caused by the presence of air bubbles in the air acting as lenses ranging in size from microscopic to roughly half the height of the laser beam's path above the earth. These atmospheric distortions coupled with the divergence of the laser itself and with transverse winds that serve to push the atmospheric heat bubbles laterally may combine to make it difficult to get an accurate reading of the distance of an object, say, beneath some trees or behind bushes, or even over long distances of more than 1 km in open and unobscured desert terrain. Some of the laser light might reflect off leaves or branches which are closer than the object, giving an early return and a reading which is too low. Alternatively, over distances longer than 1200 ft (365 m), the target, if in proximity to the earth, may simply vanish into a mirage, caused by temperature gradients in the air in proximity to the heated surface bending the laser light.
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The European X-ray Observatory Satellite (EXOSAT), originally named HELOS, was an X-ray telescope operational from May 1983 until April 1986 and in that time made 1780 observations in the X-ray band of most classes of astronomical object including active galactic nuclei, stellar coronae, cataclysmic variables, white dwarfs, X-ray binaries, clusters of galaxies, and supernova remnants. This European Space Agency (ESA) satellite for direct-pointing and lunar-occultation observation of X-ray sources beyond the solar system was launched into a highly eccentric orbit (apogee 200,000 km, perigee 500 km) almost perpendicular to that of the moon on 26 May 1983. The instrumentation includes two low-energy imaging telescopes (LEIT) with Wolter I X-ray optics (for the 0.04–2 keV energy range), a medium-energy experiment using Ar/CO2 and Xe/CO2 detectors (for 1.5–50 keV), a Xe/He gas scintillation spectrometer (GSPC) (covering 2–80 keV), and a reprogrammable onboard data-processing computer. Exosat was capable of observing an object (in the direct-pointing mode) for up to 80 hours and of locating sources to within at least 10 arcsec with the LEIT and about 2 arcsec with GSPC.
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Since 2013 he has been the chair of the Electronic Engineering bachelor and master programs of the Sapienza University of Rome and since 2018 the vice-chair of the Master program (Laurea Magistrale) in Atmospheric Science and Technology (LMAST), a joint MSc program between Sapienza University of Rome and University of L'Aquila. Since 2017 he is also the chair of IEEE Geoscience and Remote Sensing Chapter of Central-North Italy (GRS29-CNI). The research of Dr. Frank S. Marzano, published in more than 200 peer-reviewed papers, concerns passive and active remote sensing of the atmosphere from ground-based , airborne , and spaceborne platforms , development of inversion methods , radiative transfer modeling of scattering media as well as radar meteorology and microwave volcanology from ground and space . He is also involved on radiopropagation and optical propagation topics in relation to incoherent wave modeling , scintillation prediction , free space optics and rain fading analysis along terrestrial and satellite links for deep space . Dr. Marzano has published more than 150 papers on international refereed journals, 30 book chapters and more than 350 extended abstracts in conference proceedings. He co-edited a book on satellite remote sensing and ground-based remote sensing for Springer-Verlag (Berlin, Germany) in 2002 and 2010 .
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