It works by using electrodes to ionise a gas in such a way that the resulting ions (charged particles) create thrust.
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At 5 mJ in 100 femtoseconds, the peak power of such a laser is 50 gigawatts. When focused by a lens, these laser pulses will ionise any material placed in the focus, including air molecules.
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This implies the material is ionized in the polar jet, and recombines as it moves away from the star, rather than being ionized by later collisions. Shocking at the end of the jet can re-ionise some material, giving rise to bright "caps".
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Typically, monatomic oxygen plasma is created by exposing oxygen gas at a low pressure (O2) to high power radio waves, which ionise it. This process is done under vacuum in order to create a plasma. As the plasma is formed, many free radicals are created which could damage the wafer. Newer, smaller circuitry is increasingly susceptible to these particles.
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This photo shows the sterilisation effects of negative air ionization on a chamber aerosolised with Salmonella enteritidis. The left sample is untreated; the right, treated. Photo taken in a lab operated by the United States Department of Agriculture. An air ioniser (or negative ion generator or Chizhevsky's chandelier) is a device that uses high voltage to ionise (electrically charge) air molecules.
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The primary star is thought to be a post-AGB star, a highly evolved star that has ceased fusion and is ejecting its outer layers on its way to becoming a white dwarf. Although many post-AGB stars become planetary nebulae once they become hot enough to ionise their ejected outer layers, it is thought that IRAS 08544−4431 is not massive enough to do this.
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LiHe is polar and paramagnetic. The average separation between the lithium and helium atoms depends on the isotope. For 6LiHe the separation is 48.53 Å, but for 7LiHe the distance is much smaller at 28.15 Å on average. If the helium atom of LiHe is excited so that the 1s electron is promoted to 2s, it decays by transferring energy to ionise lithium, and the molecule breaks up.
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His laser systems exploit resonant four-wave mixing, which allows them to photodissociate gases observed in planetary atmospheres. He also showed that it is possible to ionise the resulting atomic fragments using a velocity imaging time-of-flight mass spectrometer. In 1996 The Planetary Society named asteroid 1081 EE37 as (4322) Billjackson in his honour. He served as Chair of the Department of Chemistry at University of California, Davis in 2000.
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The gas then scatters from the surface and is collected into a detector. In order to measure the flux of the neutral helium atoms, they must first be ionised. The inertness of helium that makes it a gentle probe now means that it is difficult to ionise and therefore reasonably aggressive electron bombardment is typically used to create the ions. A mass spectrometer setup is then used to select only the helium ions for detection.
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All alkali metals melt as a part of the reaction with water. Water molecules ionise the bare metallic surface of the liquid metal, leaving a positively charged metal surface and negatively charged water ions. The attraction between the charged metal and water ions will rapidly increase the surface area, causing an exponential increase of ionisation. When the repulsive forces within the liquid metal surface exceeds the forces of the surface tension, it vigorously explodes.
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Theremin recalled that while still in his last year of school, he had built a million- volt Tesla coil and noticed a strong glow associated with his attempts to ionise the air. He then wished to further investigate the effects using university resources. A chance meeting with Abram Fedorovich Ioffe led to a recommendation to see Karl Karlovich Baumgart, who was in charge of the physics laboratory equipment. Karl then reserved a room and equipment for Theremin's experiments.
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G–M tubes will not detect neutrons since these do not ionise the gas. However, neutron- sensitive tubes can be produced which either have the inside of the tube coated with boron, or the tube contains boron trifluoride or helium-3 as the fill gas. The neutrons interact with the boron nuclei, producing alpha particles, or directly with the helium-3 nuclei producing hydrogen and tritium ions and electrons. These charged particles then trigger the normal avalanche process.
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Negative ion track formation in the DRIFT detector. The DRIFT detector's target material is a 1 m3 cubical drift chamber filled with a low pressure mixture of carbon disulfide (CS2) and carbon tetrafluoride (CF4) gases (, respectively). It is predicted that WIMPs will occasionally collide with the nucleus of a sulfur or carbon atom in the carbon disulfide gas causing the nucleus to recoil. An energetic recoiling nucleus will ionise gas particles creating a path of free electrons.
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Accelerated by this field, the electron reaches enough energy to produce ion/electron pairs that will also ionise the gas, creating pairs; it is the avalanche effect (4). By this means, several thousand pairs are created from hundreds of primary charges, which originate from the interactions with the impinging particle. The primary charges need to be multiplied to create a significant signal. A last, we read the electronic signal on the readout electrode (5) by a charge amplifier.
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Three time projection chambers (TPCs) are gas-tight rectangular boxes, with a cathode plane in the centre and readout MicroMegas modules at both sides parallel to the cathode. TPCs are filled with argon-based drift gas under atmospheric pressure. Charged particles crossing TPC ionise the gas along their track. The ionisation electrons drift from the cathode to the sides of the TPC, where they are detected by the MicroMegas providing a 3D image of a path of the traversing charged particle.
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The acid base setting reaction begins with the mixing of the components. The first phase of the reaction involves dissolution. The acid begins to attach the surface of the glass particles, as well as the adjacent tooth substrate, thus precipitating their outer layers but also neutralising itself. As the pH of the aqueous solution rises, the polyacrylic acid begins to ionise, and becoming negatively charged it sets up a diffusion gradient and helps draw cations out of the glass and dentine.
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As helium is heated it becomes more ionised, which is more opaque. So at the dimmest part in the cycle the star has highly ionised opaque helium in its atmosphere blocking part of the light from escaping. The energy from this “blocked light” causes the helium to heat up, expand, ionise, become more transparent and therefore allow more light through. As more light is let through the star appears brighter and, with the expansion, the helium begins to cool down.
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These findings have led the research team to conclude that J0925 can ionise intergalactic material up to 40 times its own stellar mass. The study was a result of observations carried out using the Cosmic Origins Spectrograph aboard the Hubble Space Telescope. GP J0925 is thought to be similar to the most distant, and thus earliest, galaxies in the universe and has been shown to 'leak' LyC. It is about 3 billion light years away (redshift z=0.301), or approximately 75% of the current age of the universe.
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These requests were turned down. At the time there was no obvious military use, so the concept was left unclassified. This allowed Thomson and Moses Blackman to file a patent on the idea in 1946, describing a device using just enough pinch current to ionise and briefly confine the plasma while being heated by a microwave source that would also continually drive the current. As a practical device there is an additional requirement, that the reaction conditions last long enough to burn a reasonable amount of the fuel.
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When the pulse ended the gas would rapidly de-ionise, allowing signals to flow across (or around) the cavity and reach the output. Skinner took up development of the concept with Ward and Starr, initially trying helium and hydrogen, but eventually settling on a tiny amount of water vapour and argon. The resulting design, known as a soft Sutton tube, went into production as the CV43 and the first examples arrived in the summer of 1941. This testing also demonstrated two unexpected and ultimately very useful features of the spiral scan system.
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Solid samples can also be introduced using laser ablation. The sample enters the central channel of the ICP, evaporates, molecules break apart, and then the constituent atoms ionise. At the temperatures prevailing in the plasma a significant proportion of the atoms of many chemical elements are ionized, each atom losing its most loosely bound electron to form a singly charged ion. The plasma temperature is selected to maximise ionisation efficiency for elements with a high first ionisation energy, while minimising second ionisation (double charging) for elements that have a low second ionisation energy.
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While passing through the detector, a particle will ionise the gas atoms by pulling up an electron creating an electron/ion pair (1). When no electric field is applied, the ion/electron pair recombines and nothing happens. But here, within an electric field in the order of 400 V/cm the electron will drift (2) toward the amplification electrode (the mesh) and the ion toward the cathode. When the electron arrives close to the mesh (3), it enters an intense electric field (typically on the order of 40 kV/cm in the amplification gap).
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Rapidly the insulator becomes filled with mobile charge carriers, and its resistance drops to a low level. In a solid, the breakdown voltage is proportional to the band gap energy. When corona discharge occurs, the air in a region around a high- voltage conductor can break down and ionise without a catastrophic increase in current. However, if the region of air breakdown extends to another conductor at a different voltage it creates a conductive path between them, and a large current flows through the air, creating an electric arc.
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As stars are born within a GMC, the most massive will reach temperatures hot enough to ionise the surrounding gas. Soon after the formation of an ionising radiation field, energetic photons create an ionisation front, which sweeps through the surrounding gas at supersonic speeds. At greater and greater distances from the ionising star, the ionisation front slows, while the pressure of the newly ionised gas causes the ionised volume to expand. Eventually, the ionisation front slows to subsonic speeds, and is overtaken by the shock front caused by the expansion of the material ejected from the nebula.
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Fig. 1. The surface of a MEMS device is cleaned with bright, blue oxygen plasma in a plasma etcher to rid it of carbon contaminants. (100mTorr, 50W RF) Plasma cleaning is the removal of impurities and contaminants from surfaces through the use of an energetic plasma or dielectric barrier discharge (DBD) plasma created from gaseous species. Gases such as argon and oxygen, as well as mixtures such as air and hydrogen/nitrogen are used. The plasma is created by using high frequency voltages (typically kHz to >MHz) to ionise the low pressure gas (typically around 1/1000 atmospheric pressure), although atmospheric pressure plasmas are now also common.
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The deliming process can be done with acids that can be rapid in their pH adjustment. Buffering salts like ammonium salts predominated the 20th century. Ammonium sulfate and ammonium chloride can be used as deliming agents and they follow the following chemistry: :(NH4)SO4 → NH4+ (ammonium) + SO42− (sulfate) The ammonium ion is then free to penetrate the pelt cross-section and further ionise to act as an acid: :NH4+ (ammonium) + H2O → NH3 (ammonia) + H3O+ (hydronium) The protons can then serve two functions, namely to protonate basic groups of the collagen and neutralize solution alkali chemicals. Other weak acids can be used such as boric acid.
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The team had originally predicted that the system would have a practical detection range on the order of , but never managed to stretch this much beyond 3 miles. Much of this was due to the inefficient system being used to blank out the receiver during the transmission pulse, which wasted most of the radio energy. This final piece of the puzzle was provided by Arthur Cooke, who suggested using the Sutton tube filled with a dilute gas as a switch, replacing the spark gap system. During transmission, the power of the magnetron would cause the gas to ionise, presenting an almost perfect radio mirror that would prevent the signal from reaching the output.
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Plot of variation of ionisation current against applied voltage for a co-axial wire cylinder gaseous radiation detector. Townsend avalanche discharges are fundamental to the operation of gaseous ionisation detectors such as the Geiger–Müller tube and the proportional counter in either detecting ionising radiation or measuring its energy. The incident radiation will ionise atoms or molecules in the gaseous medium to produce ion pairs, but different use is made by each detector type of the resultant avalanche effects. In the case of a GM tube the high electric field strength is sufficient to cause complete ionisation of the fill gas surrounding the anode from the initial creation of just one ion pair.
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To make gaseous ions from elements it is necessary to atomise the elements (turn each into gaseous atoms) and then to ionise the atoms. If the element is normally a molecule then we first have to consider its bond dissociation enthalpy (see also bond energy). The energy required to remove one or more electrons to make a cation is a sum of successive ionization energies; for example, the energy needed to form Mg2+ is the ionization energy required to remove the first electron from Mg, plus the ionization energy required to remove the second electron from Mg+. Electron affinity is defined as the amount of energy released when an electron is added to a neutral atom or molecule in the gaseous state to form a negative ion.
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However, if the ICP-MS is to be used routinely and is on and running for eight or more hours each day for several days a week, then going with liquid argon will be the most suitable. If there are to be multiple ICP-MS instruments running for long periods of time, then it will most likely be beneficial for the laboratory to install a bulk or micro bulk argon tank which will be maintained by a gas supply company, thus eliminating the need to change out tanks frequently as well as minimizing loss of argon that is left over in each used tank as well as down time for tank changeover. Helium can be used either in place of, or mixed with, argon for plasma generation. Helium's higher first ionisation energy allows greater ionisation and therefore higher sensitivity for hard-to-ionise elements.
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To make experiments under reactor-like conditions possible, essential plasma properties, particularly the plasma density and pressure and the wall load, have been adapted in ASDEX Upgrade to the conditions that will be present in a future fusion power plant. ASDEX Upgrade is, compared to other international tokamaks, a midsize tokamak experiment. It began operation in 1991 and it succeeds the ASDEX experiment, which was in operation from 1980 until 1990. One innovative feature of the ASDEX Upgrade experiment is its all-tungsten first wall; tungsten is a good choice for the first wall of a tokamak because of its very high melting point (over 3000 degrees Celsius) which enables it to stand up to the very high heat fluxes emanating from the hot plasma at the heart of the tokamak; however there are also problems associated with a tungsten first wall, such as tungsten's tendency to ionise at high temperatures, "polluting" the plasma and diluting the deuterium-tritium fuel mix.
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