WordNet
- the electrode that is the source of electrons in a cathode-ray tube or electron microscope; consists of a cathode that emits a stream of electrons and the electrostatic or electromagnetic apparatus that focuses it
- shoot with a gun
- a weapon that discharges a missile at high velocity (especially from a metal tube or barrel)
- the discharge of a firearm as signal or as a salute in military ceremonies; "two runners started before the gun"; "a twenty gun salute"
- an elementary particle with negative charge (同)negatron
- a unit of force equal to the force exerted by gravity; used to indicate the force to which a body is subjected when it is accelerated (同)gee, g-force
PrepTutorEJDIC
- 『銃』,『砲』 / (銃に似た)吹き付け(注入)器具 / (合図・儀礼としての)銃砲の発射;礼砲,祝砲,弔砲 / …‘を'銃で撃つ / 《話》(速度を増すために)〈エンジンなど〉‘の'紋り弁を急に開いてガソリンを送る / 銃で撃つ;銃で猟をする
- 『電子』,エレクトロン
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出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2013/05/03 13:02:56」(JST)
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Electron gun from a cathode ray tube
Electron gun from an oscilloscope CRT
An electron gun (also called electron emitter) is an electrical component that produces an electron beam that has a precise kinetic energy and is most often used in television sets and computer displays that use cathode ray tube (CRT) technology, as well as in other instruments, such as electron microscopes and particle accelerators. Electron guns may be classified in several ways:
- by the type of electric field generation (DC or RF),
- by emission mechanism (thermionic, photocathode, cold emission, plasmas source),
- by focusing (pure electrostatic or with magnetic fields), or
- by the number of electrodes.
Contents
- 1 Characteristics
- 2 Applications
- 3 See also
- 4 External links
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Characteristics
A direct current, electrostatic thermionic electron gun is formed from several parts: a hot cathode, which is heated to create a stream of electrons via thermionic emission, electrodes generating an electric field which focus the beam (such as a Wehnelt cylinder), and one or more anode electrodes which accelerate and further focus the electrons. A large voltage between the cathode and anode accelerates the electrons. A repulsive ring placed between them focuses the electrons onto a small spot on the anode at the expense of a lower extraction field strength on the cathode surface. Often at this spot is a hole so that the electrons that pass through the anode form a collimated beam and finally reach a second anode called a collector. This arrangement is similar to an Einzel lens.
An ion gun consists of a cylinder where gas enters from one end face, undergoes electron bombardment from the side walls, and is subjected to an extraction voltage from the other end face. The entire cage has the role of the cathode; the extractor acts as the anode, and an unnamed ring takes the role of the Wehnelt cylinder.
Most color cathode ray tubes – such as those used in color televisions – incorporate three electron guns, each one producing a different stream of electrons. Each stream travels through a shadow mask where the electrons will impinge upon either a red, green or blue phosphor to light up a color pixel on the screen. The resultant color that is seen by the viewer will be a combination of these three primary colors.
Applications
The most common use of electron guns is in cathode ray tubes, which were widely used in computer and television monitors. An electron gun can also be used to ionize particles by adding or removing electrons from an atom. This technology is sometimes used in mass spectrometry in a process called electron ionization to ionize vaporized or gaseous particles. More powerful electron guns are used for welding, metal coating, 3D metal printers, metal powder production and vacuum furnaces.
See also
- Optics
- Electron beam technology
External links
- Howstuffworks.com: electron gun
- Charged Particle Beams, free text with material on electron gun design
- Jones, Lee. "Electron Gun". Backstage Science. Brady Haran.
UpToDate Contents
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English Journal
- 3D Atomic Imaging by Internal-Detector Electron Holography.
- Uesaka A, Hayashi K, Matsushita T, Arai S.SourceTohoku Techno Arch Company, Limited, Sendai 980-8577, Japan and HORIBA Limited, Kyoto, 601-8510, Japan.
- Physical review letters.Phys Rev Lett.2011 Jul 22;107(4):045502. Epub 2011 Jul 19.
- A method of internal-detector electron holography is the time-reversed version of photoelectron holography. Using an energy-dispersive x-ray detector, an electron gun, and a computer-controllable sample stage, we measured a multiple-energy hologram of the atomic arrangement around the Ti atom in SrT
- PMID 21867018
- Variation of the chemical contents and morphology of gunshot residue in the surroundings of the shooting pistol as a potential contribution to a shooting incidence reconstruction.
- Bro?ek-Mucha Z.SourceInstitute of Forensic Research, Westerplatte St. 9, 31-033 Krakow, Poland; Jagiellonian University, Faculty of Chemistry, Ingardena St. 3, 30-060 Krakow, Poland. zbrozek@ies.krakow.pl
- Forensic science international.Forensic Sci Int.2011 Jul 15;210(1-3):31-41. Epub 2011 Feb 26.
- A study of the chemical contents and sizes of gunshot residue originating from 9×18mm PM ammunition, depositing in the vicinity of the shooting person was performed by means of scanning electron microscopy and energy dispersive X-ray spectrometry. Samples of the residue were collected from targets
- PMID 21354728
Japanese Journal
- Characterization of Deposited Films and the Electron Beam Generated in the Pulsed Plasma Deposition Gun
- Yarmolich Dmitry,Nozar Petr,Gleizer Svetlana,Krasik Yakov E.,Mittica Giuseppe,Ancora Cosimo,Brillante Aldo,Bilotti Ivano,Taliani Carlo
- Jpn J Appl Phys 50(8), 08JD03-08JD03-5, 2011-08-25
- … The channel spark discharge was used as a high-current density (up to 30 kA/cm2) relatively low-energy (${<}20$ keV) electron beam source in a pulsed plasma deposition (PPD) gun. … The PPD gun was used for the deposition of thin films by pulsed ablation of different target materials, at a background gas pressure in the $10^{-3}$--$10^{-5}$ Torr range. …
- NAID 150000057790
- Back bombardment for dispenser and lanthanum hexaboride cathodes
- Bakr Mahmoud,Kinjo R.,Choi Y.,Omer M.,Yoshida K.,Ueda S.,Takasaki M.,Ishida K.,Kimura N.,Sonobe T.,Kii T.,Masuda K.,Ohgaki H.,Zen H.
- Physical Review Special Topics - Accelerators and Beams 14(6), 2011-06
- … This paper presents a comparison of the BB effect for the case of dispenser tungsten-base (DC) and lanthanum hexaboride (LaB6) thermionic rf gun cathodes. … For each, particle simulation codes are used to simulate the BB effect and electron beam dynamics in a thermionic rf gun cathode. … This is done by solving two differential equations for the rf gun cavity equivalent circuit and one-dimensional thermal diffusion equation. …
- NAID 120003324584
Related Links
- An electron gun (also called electron emitter) is an electrical component that produces an electron beam that has a precise kinetic energy and is most often used in television sets and computer displays which use cathode ray tube (CRT) ...
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