Carbon Nanotube Electron Gun

Science.gov (United States)

Nguyen, Cattien V. (Inventor); Ribaya, Bryan P. (Inventor)

2013-01-01

An electron gun, an electron source for an electron gun, an extractor for an electron gun, and a respective method for producing the electron gun, the electron source and the extractor are disclosed. Embodiments provide an electron source utilizing a carbon nanotube (CNT) bonded to a substrate for increased stability, reliability, and durability. An extractor with an aperture in a conductive material is used to extract electrons from the electron source, where the aperture may substantially align with the CNT of the electron source when the extractor and electron source are mated to form the electron gun. The electron source and extractor may have alignment features for aligning the electron source and the extractor, thereby bringing the aperture and CNT into substantial alignment when assembled. The alignment features may provide and maintain this alignment during operation to improve the field emission characteristics and overall system stability of the electron gun.

Electron guns for accelerators

International Nuclear Information System (INIS)

Rangarajan, L.M.; Mahadevan, S.; Ramamurthi, S.S.

1995-01-01

The high voltage, high current electron guns developed elsewhere for Linacs are based on cathode pulsing with direct emitting cathodes. Our grid pulsed triode gun employs indirect emitting cathode pellet under electron bombardment or a direct cathode emitter. Electron beam from the gun is injected to the accelerator guide at 40 kV and pulse duration is 2.8μsec. The gun is limited to axially symmetric geometry and electron optical design is optimized by computer programming. The gun with a water cooled Faraday cup is connected to a vacuum system comprising of a sputter ion pump and sorption pump. Working pressure is 1x10 -6 Pa. Gun is designed to be baked as an assembly at temperatures of 400 degC while vacuum processing. Materials are therefore restricted to refractory metals, SS, OFHC copper and all the electrodes are housed inside a ceramic tube. Lower Z graphite is used as a base material of Faraday cup. Grid is non-intercepting modulator anode, a new feature introduced, as compared to meshed grid system by others. CAT gun delivers 160 mA current pulses at 40 kV and its working characteristics such as perveance, emittance and beam radius compare well with SLAC and Hermosa guns. The above guns can be used for electron beam machines such as medical Linacs, industrial accelerators and EB welding equipment. (author). 2 refs., 2 figs

Low emittance thermionic electron guns

International Nuclear Information System (INIS)

Herrmannsfeldt, W.B.

1989-01-01

The author discusses self-field effects and external field effects for electron guns. He also discusses designs of electron guns and their uses in electron cooling systems and as an injector for electrostatic free electron lasers. He closes by looking at electron guns for linear accelerators. 20 references, 3 figures

Unbalanced field RF electron gun

Science.gov (United States)

Hofler, Alicia

2013-11-12

A design for an RF electron gun having a gun cavity utilizing an unbalanced electric field arrangement. Essentially, the electric field in the first (partial) cell has higher field strength than the electric field in the second (full) cell of the electron gun. The accompanying method discloses the use of the unbalanced field arrangement in the operation of an RF electron gun in order to accelerate an electron beam.

Optimization of beam parameters of electron gun for 2.5 MeV/100 kW high power industrial accelerator

International Nuclear Information System (INIS)

Pramod, R.; Petwal, V.C.

2009-01-01

A 2.5 MeV/100 kW transformer type industrial accelerator is being developed at RRCAT. A Pierce type electron gun consisting of 10 mm diameter LaB 6 disc (indirectly heated) is used as a source of electron beam. The cathode assembly is put on the top of the accelerating structure, which consists of many electrostatic lenses of which the first lens acts as anode of the gun. The quality of the beam injected into the accelerating structure depends on the anode voltage, shape and size of anode and its distance from the cathode. The anode is subjected to variable voltage during the operation of accelerator from energy 1 MeV to 2.5 MeV, which results in variable emittance at the exit of the electron gun. The electron beam from the gun should provide parallel or slightly convergent beam with long focal length and the emittance of the beam at the exit of electron gun should match the beam acceptance limit of the accelerating structure. The EGUN code is used to optimize the shape and size of the anode, its distance from the cathode to achieve above objectives. Our study suggests that the desired beam parameters at the exit of the anode can be obtained by reducing the aperture size of the anode and by applying suitable voltage gradient to the anode. (author)

The ALS Gun Electronics system

International Nuclear Information System (INIS)

Lo, C.C.

1993-05-01

The ALS Gun Electronics system has been designed to accommodate gun with a custom made socket and high speed electronics circuit which is capable of producing single and multiple electron bunches with time jitters measured at better than 50 PS. The system generates the gated RF signal at ground level before sending it up to the 120 KV-biased gun deck via a fiber optic cable. The current pulse width as a function of grid bias, using an Eimac 8847A planar triode simulating an electron gun, was measured to show the relationship between the two parameters

The ALS gun electronics system

International Nuclear Information System (INIS)

Lo, C.C.

1993-01-01

The ALS Gun Electronics system has been designed to accommodate the gun with a custom made socket and a high speed electronics circuit which is capable of producing single and multiple electron bunches with time jitters measured at better than 50 PS. The system generates the gated RF signal at ground level before sending it up to the 120 KV-biased gun deck via a fiber optic cable. The current pulse width as a function of grid bias, using an Eimac 8847A planar triode simulating an electron gun, was measured to show the relationship between the two parameters

ORELA electron guns

International Nuclear Information System (INIS)

Christian, O.W.; Lewis, T.A.

1981-09-01

The most recent information concerning the production and performance of ORELA electron guns is presented. Included are descriptions of procedures for gun fabrication, cathode conditioning and high voltage processing. Highlights of the performance characteristics are also included

Ion plasma electron gun

International Nuclear Information System (INIS)

Wakalopulos, G.

1976-01-01

In the disclosed electron gun positive ions generated by a hollow cathode plasma discharge in a first chamber are accelerated through control and shield grids into a second chamber containing a high voltage cold cathode. These positive ions bombard a surface of the cathode causing the cathode to emit secondary electrons which form an electron beam having a distribution adjacent to the cathode emissive surface substantially the same as the distribution of the ion beam impinging upon the cathode. After passing through the grids and the plasma discharge chamber, the electron beam exits from the electron gun via a foil window. Control of the generated electron beam is achieved by applying a relatively low control voltage between the control grid and the electron gun housing (which resides at ground potential) to control the density of the positive ions bombarding the cathode

Electronic emission and electron guns

International Nuclear Information System (INIS)

Roy, Amitava

2010-01-01

This paper reviews the process of electron emission from metal surface. Although electrons move freely in conductors like metals, they normally do not leave the metal without some manipulation. In fact, heating and bombardment are the two primary ways in which electrons are emitted through the use of a heating element behind the cathode (termed thermionic emission) or as a result of bombardment with a beam of electrons, ions, or metastable atoms (termed secondary emission). Another important emission mechanism called Explosive Electron Emission (EEE) is also often used in various High Voltage Pulse Power Systems to generate very high current (few hundreds of kA) pulsed electron beams. The electron gun is the device in that it shoots off a continuous (or pulsed) stream of electrons. A brief idea about the evolution of the electron gun components and their basis of functioning are also discussed. (author)

ECR ion source with electron gun

Science.gov (United States)

Xie, Zu Q.; Lyneis, Claude M.

1993-01-01

An Advanced Electron Cyclotron Resonance ion source (10) having an electron gun (52) for introducing electrons into the plasma chamber (18) of the ion source (10). The ion source (10) has a injection enclosure (12) and a plasma chamber tank (14). The plasma chamber (18) is defined by a plurality of longitudinal magnets (16). The electron gun (52) injects electrons axially into the plasma chamber (18) such that ionization within the plasma chamber (18) occurs in the presence of the additional electrons produced by the electron gun (52). The electron gun (52) has a cathode (116) for emitting electrons therefrom which is heated by current supplied from an AC power supply (96) while bias potential is provided by a bias power supply (118). A concentric inner conductor (60) and Outer conductor (62) carry heating current to a carbon chuck (104) and carbon pusher (114) Which hold the cathode (116) in place and also heat the cathode (16). In the Advanced Electron Cyclotron Resonance ion source (10), the electron gun (52) replaces the conventional first stage used in prior art electron cyclotron resonance ion generators.

Electron gun for SSRF

International Nuclear Information System (INIS)

Sheng Shugang; Lin Guoqiang; Gu Qiang; Li Deming

2003-01-01

A 100 kV triode-electron-gun has been designed and manufactured for the Linac of Shanghai Synchrotron Radiation Facility (SSRF). In this paper the performance of the gun and some key components are described

Simulation of electron beam from two strip electron guns and control of power density by rotation of gun

International Nuclear Information System (INIS)

Sahu, G K; Baruah, S; Thakur, K B

2012-01-01

Electron beam is preferably used for large scale evaporation of refractory materials. Material evaporation from a long and narrow source providing a well collimated wedge shaped atomic beam has applications in isotopic purification of metals relevant to nuclear industry. The electron beam from an electron gun with strip type filament provides a linear heating source. However, the high power density of the electron beam can lead to turbulence of the melt pool and undesirable splashing of molten metal. For obtaining quiet surface evaporation, the linear electron beam is generally scanned along its length. To further reduce the power density to maintain quiet evaporation the width of the vapour source can be controlled by rotating the electron gun on its plane, thereby scanning an inclined beam over the molten pool. The rotation of gun has further advantages. When multiple strip type electron guns are used for scaling up evaporation length, a dark zone appears between two beams due to physical separation of adjacent guns. This dark zone can be reduced by rotating the gun and thereby bringing two adjacent beams closer. The paper presented here provides the simulation results of the electron beam trajectory and incident power density originating from two strip electron guns by using in-house developed code. The effect of electron gun rotation on the electron beam trajectory and power density is studied. The simulation result is experimentally verified with the image of molten pool and heat affected zone taken after experiment. This technique can be gainfully utilized in controlling the time averaged power density of the electron beam and obtaining quiet evaporation from the metal molten pool.

Gun power source for electron gun of 3 MeV DC accelerator

International Nuclear Information System (INIS)

Dewangan, S.; Sharma, D.K.; Nanu, K.

2011-01-01

In DC electron beam accelerator electron gun is situated at high voltage terminal which requires constant power irrespective of beam energy. Floating power source is required for gun. This paper describes the scheme of static gun power source derived from parallel coupled voltage multiplier column. (author)

Pseudomonas aeruginosa necrotizing chondritis complicating high helical ear piercing case report: clinical and public health perspectives.

Science.gov (United States)

Sandhu, Amonpreet; Gross, Melissa; Wylie, John; Van Caeseele, Paul; Plourde, Pierre

2007-01-01

Auricular or high helical ear piercing is an increasingly widespread fashion trend that is associated with an increased risk of potentially serious post-piercing complications such as auricular perichondritis. An 11-year-old girl developed severe auricular perichondritis following piercing of the upper helical cartilage of her ear at a hairdressing salon. Four days post piercing, she returned to the same salon for a haircut during which the pierced site was manipulated. She presented to her family physician and was treated unsuccessfully with oral cephalexin. She was then referred to an infectious diseases consultant and received antipseudomonal intravenous antibiotics with subsequent resolution. She also required debridement and removal of necrotic cartilage. Public health investigation evaluated potential sources of infection including the piercing gun, disinfectant solutions, and hair cutting spray water bottles. Final culture results of the ear helical aspirate grew Pseudomonas aeruginosa. Pseudomonas aeruginosa was also cultured from one of the water bottles used to wet her hair during the haircut. Although the pseudomonal strains from the water bottle were different than the infecting one, this contamination presents a potential source of wound infection. Damage to the helical cartilage caused by the piercing gun may also have contributed to this infection. Initial empiric antibiotic therapy for these kinds of infection must include anti-pseudomonal coverage. Auricular or high helical ear piercing using a piercing gun is not recommended.

Practical XHV electron gun

International Nuclear Information System (INIS)

Urata, Tomohiro; Ishikawa, Tsuyoshi; Cho, Boklae; Oshima, Chuhei

2008-01-01

We have developed practical XHV chambers of a electron gun, of which the operating pressures are 1x10 -9 Pa in a stainless-steel one and 4x10 -9 Pa in a permalloy one. By mounting a noble single-atom electron source with high brightness and high spatial coherence on the electron gun including electron optics, we demonstrated highly collimated electron-beam emission: ∼80% of the total emission current entered the electron optics. This ratio was two or three orders of magnitude higher than those of the conventional electron sources. In XHV, in addition, we confirmed stable electron emission up to 20 nA, which results in the specimen current high enough for scanning electron microscopes. (author)

Electron gun for technological linear accelerator

International Nuclear Information System (INIS)

Khodak, I.V.; Kushnir, V.A.; Mirochenko, V.V.; Stepin, D.L.; Zavada, L.M.

2000-01-01

The work is purposed to the design of diode electron gun for powerful technologic electron linac and to experimental investigations of the beam parameters at the gun exit.The gun feature is the quick cathode replacement.This is very impotent for operating of the accelerator.The gun optics and beam parameters were calculated using the EGUN code.Beam parameters were investigated as at the special test stand so as component of the linac injector.The gun produces the beam current of 2 A at the anode voltage 25 kV.Measured beam parameters correspond to calculated results

Electron gun for the Fel Clio

International Nuclear Information System (INIS)

Chaput, R.

1990-01-01

A triode electron gun has been developed and manufactured at LURE (Laboratoire pour l'Utilisation du Rayonnement Electromagnetique) and LAL (Laboratoire de l'Accelerateur Lineaire) for the free electron laser CLIO 1 (Collaboration pour un laser a electrons libres dans l'infrarouge a Orsay) now under construction: this gun involves a grid-cathode assembly manufactured by EIMAC, currently used in the SLAC gun family. For the FEL requirements, the gun must be able to yield a train of short pulses at accuracy frequency or a continuous pulse. Driving together the cathode and the grid the gun produces a continous beam of 12 μs or a pulsed beam of very short pulse of 1 ns at 250 MHz, 125 MHz, 62.5 MHz or 31.25 MHz. The performances of the gun has been tested on a testing bench. A peak current of 1 Amp. for 1 ns width at any frequencies was achieved at an injection voltage of 90 kV

High perveance electron gun for the electron cooling system

International Nuclear Information System (INIS)

Korotaev, Yu.; Meshkov, I.; Petrov, A.; Sidorin, A.; Smirnov, A.; Syresin, E.; Titkova, I.

2000-01-01

The cooling time in the electron cooling system is inversely proportional to the beam current. To obtain high current of the electron beam the control electrode of the gun is provided with a positive potential and an electrostatic trap for secondary electrons appears inside the electron gun. This leads to a decrease in the gun perveance. To avoid this problem, the adiabatic high perveance electron gun with the clearing control electrode is designed in JINR (J. Bosser, Y. Korotaev, I. Meshkov, E. Syresin et al., Nucl. Instr. and Meth. A 391 (1996) 103. Yu. Korotaev, I. Meshkov, A. Sidorin, A. Smirnov, E. Syresin, The generation of electron beams with perveance of 3-6 μA/V 3/2 , Proceedings of SCHEF'99). The clearing control electrode has a transverse electric field, which clears secondary electrons. Computer simulations of the potential map were made with RELAX3D computer code (C.J. Kost, F.W. Jones, RELAX3D User's Guide and References Manual)

High perveance electron gun for the electron cooling system

CERN Document Server

Korotaev, Yu V; Petrov, A; Sidorin, A; Smirnov, A; Syresin, E M; Titkova, I

2000-01-01

The cooling time in the electron cooling system is inversely proportional to the beam current. To obtain high current of the electron beam the control electrode of the gun is provided with a positive potential and an electrostatic trap for secondary electrons appears inside the electron gun. This leads to a decrease in the gun perveance. To avoid this problem, the adiabatic high perveance electron gun with the clearing control electrode is designed in JINR (J. Bosser, Y. Korotaev, I. Meshkov, E. Syresin et al., Nucl. Instr. and Meth. A 391 (1996) 103. Yu. Korotaev, I. Meshkov, A. Sidorin, A. Smirnov, E. Syresin, The generation of electron beams with perveance of 3-6 mu A/V sup 3 sup / sup 2 , Proceedings of SCHEF'99). The clearing control electrode has a transverse electric field, which clears secondary electrons. Computer simulations of the potential map were made with RELAX3D computer code (C.J. Kost, F.W. Jones, RELAX3D User's Guide and References Manual).

A ferroelectric electron gun in a free-electron maser experiment

International Nuclear Information System (INIS)

Einat, M.; Jerby, E.; Rosenman, G.

2002-01-01

An electron-gun based on a ferroelectric cathode is studied in a free-electron maser (FEM) experiment. In this gun, the electrons are separated from the cathode surface plasma, and are accelerated in two stages. The electron energy-spread is reduced sufficiently for an FEM operation in the microwave regime. A 14 keV, 1-2 A e-beam is obtained in a 0.1-2.1 μs pulse width. The pulse repetition frequency attains 3.1 MHz in ∼50% duty-cycle. This gun is implemented in an FEM oscillator experiment operating around 3 GHz. The paper presents experimental results and discusses the applicability of ferroelectric guns in free-electron laser devices

A ferroelectric electron gun in a free-electron maser experiment

CERN Document Server

Einat, M; Rosenman, G

2002-01-01

An electron-gun based on a ferroelectric cathode is studied in a free-electron maser (FEM) experiment. In this gun, the electrons are separated from the cathode surface plasma, and are accelerated in two stages. The electron energy-spread is reduced sufficiently for an FEM operation in the microwave regime. A 14 keV, 1-2 A e-beam is obtained in a 0.1-2.1 mu s pulse width. The pulse repetition frequency attains 3.1 MHz in approx 50% duty-cycle. This gun is implemented in an FEM oscillator experiment operating around 3 GHz. The paper presents experimental results and discusses the applicability of ferroelectric guns in free-electron laser devices.

Control electron beam oscillation regimes in Pierce diode with overcritical current

International Nuclear Information System (INIS)

Rempen, I.S.; Khramov, A.E.

2001-01-01

The effect of the delayed feedback on the complex oscillation regimes in the electron flux with the overcritical current in the Pierce diode is studied. The possibility of controlling the oscillation regimes through changing the feedback parameters is shown. The finite-dimensional model, describing the behavior of the electron flux in the Pierce diode hydrodynamic model, is constructed. Its behavior under the effect of the delayed feedback is studied [ru

Gridded X-ray tube gun

International Nuclear Information System (INIS)

1975-01-01

An X-ray generator has a Pierce type electron gun comprising an electron emissive cathode with field shaping electrodes, a first accelerating anode spaced from the cathode, and an X-ray target anode spaced from the accelerating anode for being impinged upon by a focused electron beam. Control grid means are disposed between the cathode and the first anode. The grid means are constructed such that with use of proper grid potentials, the electron beam may be selectively biased to cutoff, or electrons can be withdrawn from selected areas of the cathode or from the entire cathode to produce focal spots of different sizes and various electron current magnitudes on the target anode

Rate control for electron gun evaporation

International Nuclear Information System (INIS)

Schellingerhout, A.J.G.; Janocko, M.A.; Klapwijk, T.M.; Mooij, J.E.

1989-01-01

Principles for obtaining high-quality rate control for electron gun evaporation are discussed. The design criteria for rate controllers are derived from this analysis. Results are presented which have been obtained with e-guns whose evaporation rate is controlled by a Wehnelt electrode or by sweeping of the electron beam. Further improvements of rate stability can be obtained by improved design of e-guns and power supplies

Electron gun

International Nuclear Information System (INIS)

Chen, H.-Y.; Hughes, R.H.

1979-01-01

The invention described relates to cathode ray tubes, and particularly to color picture tubes of the type useful in home television receivers and therefore to electron guns. The invention is especially applicable to self-converging tube-yoke combinations with shadow mask tubes of the type having plural-beam in-line guns disposed in a horizontal plane, an apertured mask with vertically oriented slit-shaped apertures, and a screen with vertically oriented phosphor stripes. The invention is not, however, limited to use in such tubes and may in fact be used, e.g., in dot-type shadow mask tubes and index-type tubes. (Auth.)

The electron gun for the Daresbury SRS linac

International Nuclear Information System (INIS)

Dykes, D.M.

1996-01-01

The electron gun for the Daresbury SRS linac injector has been modified to use the cathode-grid assembly from the Eimac planar triode 8755. The gun now has improved beam characteristics, is more reliable and the cathode assembly is quicker and easier to change. This paper describes the assembly of the electron gun, and then the re-conditioning of the cathode highlighting the vacuum environment. The action of the grid modulation system on the electron beam, which pre-bunches the electron beam, is described, and typical gun characteristics are shown. Proposed developments to the gun system are discussed. (author)

PHERMEX electron gun development

International Nuclear Information System (INIS)

Builta, L.A.; Elliott, J.C.; Moir, D.C.; Starke, T.P.; Vecere, C.A.

1983-01-01

The PHERMEX facility is a 50-MHz standing-wave linear accelerator. Electrons are injected, accelerated, and transported to a tungsten target where bremsstrahlung x rays are generated for flash radiography of hydrodynamic systems. The purpose of this article is to describe the progress of PHERMEX electron gun development. The goal of this program is to generate and transport a 200-ns, 1-MV, 1-kA electron beam into the first PHERMEX accelerating cavity. The standard gun is operated at a pulse voltage of 550 kV, which is the limit determined by internal breakdown of the vacuum insulator. This insulator has been redesigned, and the gun has been pulsed at 750 kV without internal breakdown. At present, the current output is not limited by voltage but by a phenomenon called pulse shortening, which occurs at a pulse voltage of approximately 650 kV. The phenomenon has been investigated and the results are presented

ELECTRON GUN

Science.gov (United States)

Christofilos, N.C.; Ehlers, K.W.

1960-04-01

A pulsed electron gun capable of delivering pulses at voltages of the order of 1 mv and currents of the order of 100 amperes is described. The principal novelty resides in a transformer construction which is disposed in the same vacuum housing as the electron source and accelerating electrode structure of the gun to supply the accelerating potential thereto. The transformer is provided by a plurality of magnetic cores disposed in circumferentially spaced relation and having a plurality of primary windings each inductively coupled to a different one of the cores, and a helical secondary winding which is disposed coaxially of the cores and passes therethrough in circumferential succession. Additional novelty resides in the disposition of the electron source cathode filament input leads interiorly of the transformer secondary winding which is hollow, as well as in the employment of a half-wave filament supply which is synchronously operated with the transformer supply such that the transformer is pulsed during the zero current portions of the half-wave cycle.

Highly efficient electron gun with a single-atom electron source

International Nuclear Information System (INIS)

Ishikawa, Tsuyoshi; Urata, Tomohiro; Cho, Boklae; Rokuta, Eiji; Oshima, Chuhei; Terui, Yoshinori; Saito, Hidekazu; Yonezawa, Akira; Tsong, Tien T.

2007-01-01

The authors have demonstrated highly collimated electron-beam emission from a practical electron gun with a single-atom electron source; ∼80% of the total emission current entered the electron optics. This ratio was two or three orders of magnitude higher than those of the conventional electron sources such as a cold field emission gun and a Zr/O/W Schottky gun. At the pressure of less than 1x10 -9 Pa, the authors observed stable emission of 20 nA, which generates the specimen current of 5 pA required for scanning electron microscopes

A compact electron gun using field emitter array

International Nuclear Information System (INIS)

Asakawa, M.R.; Ikeda, A.; Miyabe, N.; Yamaguchi, S.; Kusaba, M.; Tsunawaki, Y.

2008-01-01

A compact electron gun using field emitter array has been developed. With a simple triode configuration consisting of FEA, mid-electrode and anode electrode, the electron gun produces a parallel beam with a diameter of 0.5 mm. This electron gun is applicable for compact radiation sources such as Cherenkov free-electron lasers

RF Electron Gun with Driven Plasma Cathode

CERN Document Server

Khodak, Igor

2005-01-01

It's known that RF guns with plasma cathodes based on solid-state dielectrics are able to generate an intense electron beam. In this paper we describe results of experimental investigation of the single cavity S-band RF gun with driven plasma cathode. The experimental sample of the cathode based on ferroelectric ceramics has been designed. Special design of the cathode permits to separate spatially processes of plasma development and electron acceleration. It has been obtained at RF gun output electron beam with particle energy ~500 keV, pulse current of 4 A and pulse duration of 80 ns. Results of experimental study of beam parameters are referred in. The gun is purposed to be applied as the intense electron beam source for electron linacs.

Development techniques and electron optical studies of high voltage, high current electron guns

International Nuclear Information System (INIS)

Rangarajan, L.M.; Mahadevan, S.; Ramamurthi, S.S.

1992-01-01

The progress of the electron gun design, limiting to axially symmetric geometries is discussed here with a view to utilise such guns for electron accelerators. The mechanical design features leading to the physical configuration of the gun with stringent tolerances are outlined. Vacuum processing is done at pressures of 1.3x10 -5 Pa. The gun employs W-filament emitter or a cathode pellet with bombarder service. A water cooled compact faraday cup is used to measure the electron current. Electron gun geometries have been studied using the computer programme. The preveance of the gun is 0.7x10 -7 A/Vsup(1.5) at 80 kV. Developmental techniques of such pulsed electron guns are described. (author). 7 refs., 5 figs

Development of plasma cathode electron guns

Science.gov (United States)

Oks, Efim M.; Schanin, Peter M.

1999-05-01

The status of experimental research and ongoing development of plasma cathode electron guns in recent years is reviewed, including some novel upgrades and applications to various technological fields. The attractiveness of this kind of e-gun is due to its capability of creating high current, broad or focused beams, both in pulsed and steady-state modes of operation. An important characteristic of the plasma cathode electron gun is the absence of a thermionic cathode, a feature which leads to long lifetime and reliable operation even in the presence of aggressive background gas media and at fore-vacuum gas pressure ranges such as achieved by mechanical pumps. Depending on the required beam parameters, different kinds of plasma discharge systems can be used in plasma cathode electron guns, such as vacuum arcs, constricted gaseous arcs, hollow cathode glows, and two kinds of discharges in crossed E×B fields: Penning and magnetron. At the present time, plasma cathode electron guns provide beams with transverse dimension from fractional millimeter up to about one meter, beam current from microamperes to kiloamperes, beam current density up to about 100 A/cm2, pulse duration from nanoseconds to dc, and electron energy from several keV to hundreds of keV. Applications include electron beam melting and welding, surface treatment, plasma chemistry, radiation technologies, laser pumping, microwave generation, and more.

Dynamics of Pierce instability of hot electron beams

International Nuclear Information System (INIS)

Ignatov, A.M.; Novikov, V.N.

1986-01-01

On the base of a new method of numerical solution of the Vlasov equation evolution of complete function of electron distribution at the injection of hot electron beams into plasma bounded with electrodes is investigated. It is shown that despite the development of electrostatic instabilities in the system the currents can run substantially exceeding the Pierce critical current

Development of the Antares electron gun

International Nuclear Information System (INIS)

Stine, R.; Leland, W.; Mansfield, C.; Rosocha, L.; Jansen, J.; Gibson, R.; Allen, G.

1984-01-01

Antares is the Los Alamos National Laboratory 40-kJ, 1-ns, CO 2 laser system that is now operational. This laser system was developed for the Intertial Confinement Fusion (ICF) program and is beginning target experiments. The distributed circuit modeling, design and operation of the large electron gun developed for the final laser power amplifier are reviewed. This gun is significant because of the large electron current area, 9 m 2 ; the number of emitter blades, 48; the dual cathode current return; and the coaxial geometry and grid control. The gun components and their development are discussed. These include the emitter blades, the coaxial grid (to maintain constant electron current during the 5-μs pulse), the bonded stacked-ring insulator (to electrically insulate the grid/cathode), the Kapton/aluminum electron transmission windows (to provide an interface between gun vacuum and laser gas) and the vacuum shell (operated at a vacuum of 10 -6 torr). A unique pressure diagnostic is also discussed

Development of the electron gun control system of SSRF

International Nuclear Information System (INIS)

Zhou Dayong; Lin Guoqiang; Liu Dekang; Shen Liren

2010-01-01

An electron gun is the key part of a linac, the beam quality of which depends on beam quality of the electron gun, hence the need of a stable control system of the electron gun to ensure its safe operation.In this paper, we report our progresses in developing the linac's electron gun control system of Shanghai Synchrotron Radiation Facility (SSRF). It uses PLC as the device controllers, with the monitoring software developed on EPICS. The whole system is connected by Ethernet. The PLC and Ethernet technology ensures good reliability and easy maintenance of the electron gun control system. (authors)

Mechanical design of a RF electron gun

International Nuclear Information System (INIS)

Woodle, M.H.; Batchelor, K.; Sheehan, J.

1989-01-01

Brookhaven National Laboratory is building an Accelerator Test Facility at which we plan to study laser acceleration of electrons, inverse free electron lasers and the production of X-rays by non-linear Compton scattering. The facility contains an electron gun, linac, lasers and ancillary systems which will enable the production of 6 ps duration pulses of 50-100 MeV electrons. The electron source is an one and one half cell RF Electron gun which utilizes either a thermionic or photoemissive cathode to produce 5 MeV electrons. This paper discusses how gun mechanical design considerations such as material, vacuum maintenance, surface finish, fabrication methods, cavity tuning, and cathode replacement were reconciled to arrive at the final design. 9 refs., 2 figs., 2 tabs

Mechanical design of a rf electron gun

International Nuclear Information System (INIS)

Woodle, M.H.; Batchelor, K.; Sheehan, J.

1988-01-01

Brookhaven National Laboratory is building an Accelerator Test Facility at which we plan to study laser acceleration of electrons inverse free electron lasers and the production of X-rays by non- linear Compton scattering. The facility contains an electron gun, linac, lasers and ancillary systems which will enable the production of 6 ps duration pulses of 50--100 MeV electrons. The electron source is an one and one half cell RF Electron gun which utilizes either a thermionic or photoemissive cathode to produce 5 MeV electrons. This paper discusses how gun mechanical design considerations such as material, vacuum maintenance, surface finish, fabrication methods, cavity tuning, and cathode replacement were reconciled to arrive at the final design. 9 refs., 2 figs., 2 tabs

Klystron - Space-charge limited flow, guns, Perveance

International Nuclear Information System (INIS)

Isagawa, S.

1999-01-01

This paper treats Thermionic emission, Cathode as an e - emitter, Space-charge limited effect and 3/2 power law, Perveance, Beam spread due to space charge, Pierce guns, Magnetically immersed guns, Method of gun design including simulations, and Examples, mainly treating E3786, which attendees will operate above 1 MW-CW in a practical exercise course at KEK. (author). 74 refs

Design of triode electron gun for electron LINAC

International Nuclear Information System (INIS)

Prasad, M.; Pande, S.A.; Hannurkar, P.R.

2003-01-01

A 10 MeV, 10 kW, electron linear accelerator is being developed at Centre for Advanced Technology, CAT for irradiation of agricultural products such as onions and potatoes. This facility required electron beam of variable energy and power. The linac structure consists of a thermionic triode gun, TW buncher and accelerator waveguide, focusing and centering coils, beam scanning system etc. The accelerator structure is disk loaded waveguide operating in TW 27π/3 mode at 2856 MHz. The triode gun is designed for operation at 50 kV. The gun is optimized for minimum grid voltage and minimum transverse beam dimensions. In this paper, the results of our optimization studies using computer code EGUN are presented. (author)

Self-bunching electron guns

CERN Document Server

Mako, F; Weilhammer, Peter

1999-01-01

We report on three electron gun projects that are aimed at power tube and injector applications. The purpose of the work is to develop robust electron guns which produce self-bunched, high-current-density beams. We have demonstrated cold emission, long life, and tolerance to contamination. The cold emission process is based on secondary electron emission. FMT has studied this resonant bunching process which gives rise to high current densities (0.01-5 kA/cm/sup 2/), high charge bunches (up to 100 nC/bunch), and short pulses (1-100 ps) for frequencies from 1 to 12 GHz. The beam pulse width is nominally ~5% of the RF period. The first project is the L-Band Micro-Pulse Gun (MPG). Measurements show ~40 ps long microbunches at ~20 A/cm/sup 2/ without contamination due to air exposure. Lifetime testing has been carried out for about 18 months operating at 1.25 GHz for almost 24 hours per day at a repetition rate of 300 Hz and 5 mu s-long macro- pulses. About 5.8*10/sup 13/ micro-bunches or 62,000 coulombs have pass...

Development of an electron gun for high power CW electron linac (1). Beam experiment for basic performance of electron gun

International Nuclear Information System (INIS)

Yamazaki, Yoshio; Nomura, Masahiro; Komata, Tomoki

1999-05-01

Presently, the Beam Group of Oarai Engineering Center in Japan Nuclear Cycle Development Institute (JNC) completed the high power CW electron linac. Then we started full-scale beam experiments after the government permission for a radiation equipment had given last January. Measurements of basic performance for the mesh-grid type electron gun have been done to launch stable beam at 300 mA peak current downstream of the accelerator. These experiments disclosed to increase beam loss in the electron gun in some cases of voltage supplied the mesh-grid in spite of same beam current from gun. Consequently, we could find the best condition for mesh-grid voltage and heater current to supply stable beam at 300 mA peak current for accelerator study. (author)

Advances in DC photocathode electron guns

International Nuclear Information System (INIS)

Dunham M, Bruce; Heartmann, P.; Reza Kazimi; Hongxiu Liu; Poelker, B.M.; Price, J.S.; Rutt, P.M.; Schneider, W.J.; Sinclair K, Charles

1998-01-01

At Jefferson Lab, a DC photoemission gun using GaAs and GaAs-like cathodes provides a source of polarized electrons for the main accelerator. The gun is required to produce high average current with long operational lifetimes and high system throughout. Recent work has shown that careful control of the parameters affecting cathode lifetime lead to dramatic improvements in source operation. These conditions include vacuum and the related effect of ion back-bombardment, and precise control of all of the electrons emitted from the cathode. In this paper, the authors will review recent results and discuss implications for future photocathode guns

Advances in DC photocathode electron guns

International Nuclear Information System (INIS)

Dunham, B. M.; Hartmann, P.; Kazimi, R.; Liu, H.; Poelker, B. M.; Price, J. S.; Rutt, P. M.; Schneider, W. J.; Sinclair, C. K.

1999-01-01

At Jefferson Lab, a DC photoemission gun using GaAs and GaAs-like cathodes provides a source of polarized electrons for the main accelerator. The gun is required to produce high average current with long operational lifetimes and high system throughput. Recent work has shown that careful control of the parameters affecting cathode lifetime lead to dramatic improvements in source operation. These conditions include vacuum and the related effect of ion backbombardment, and precise control of all of the electrons emitted from the cathode. In this paper, we will review recent results and discuss implications for future photocathode guns

Progress on a cryogenically cooled RF gun polarized electron source

Energy Technology Data Exchange (ETDEWEB)

Fliller, R.P., III; Edwards, H.; /Fermilab

2006-08-01

RF guns have proven useful in multiple accelerator applications. An RF gun capable of producing polarized electrons is an attractive electron source for the ILC or an electron-ion collider. Producing such a gun has proven elusive. The NEA GaAs photocathode needed for polarized electron production is damaged by the vacuum environment in an RF gun. Electron and ion back bombardment can also damage the cathode. These problems must be mitigated before producing an RF gun polarized electron source. In this paper we report continuing efforts to improve the vacuum environment in a normal conducting RF gun by cooling it with liquid nitrogen after a high temperature vacuum bake out. We also report on a design of a cathode preparation chamber to produce bulk GaAs photocathodes for testing in such a gun. Future directions are also discussed.

Design of the BEPCII electron gun system

International Nuclear Information System (INIS)

Liu Bo; Gu Mengping; Chi Yunlong

2006-01-01

BEPCII upgrading project needs a new high current electron gun. The design stage such as physical design, mechanical design and control system design of this new electron gun is described. The emission current is designed to be higher than 10 A for the pulse width of 1 ns with repetition rate of 50 Hz. The gun will operate with a pulsed high voltage power supply which can provide up to 200 kV high voltage. Computer simulations and optimizations have been carried out in the design stage, including the gun geometry and beam transport. EGUN and DGUN codes are used to simulate the gun geometry, and the results show that the perveance is about 0.22 μA·V -3/2 , and the emittance at gun exit is about 16 π·mm·mrad. PARMELA code shows that the electron beam can be easily transported to the end of the first accelerating tube with a capture efficiency of 67% and root mean square emittance of 25 mm·mrad. New scheme of the gun control system based on EPICS is also presented. Two-bunch operation mode and 2.5 μs long pulse operation mode are available in the control system. (authors)

A high-brightness thermionic microwave electron gun

Energy Technology Data Exchange (ETDEWEB)

Borland, Michael [Stanford Univ., CA (United States)

1991-02-01

In a collaborative effort by SSRL, AET Associates, and Varian Associates, a high-brightness microwave electron gun using a thermionic cathode has been designed, built, tested, and installed for use with the SSRL 150 MeV linear accelerator. This thesis discusses the physics behind the design and operation of the gun and associated systems, presenting predictions and experimental tests of the gun`s performance. The microwave gun concept is of increasing interest due to its promise of providing higher-current, lower-emittance electron beams than possible from conventional, DC gun technology. In a DC guns, accelerating gradients are less than 8 MV/m, while those in a microwave gun can exceed 100 MV/m, providing much more rapid initial acceleration, thereby reducing the deleterious effects of space-charge. Microwave guns produce higher momentum beams than DC guns, thus lessening space-charge effects during subsequent beam transport. Typical DC guns produce kinetic energies of 80--400 KeV, compared to 2--3 MeV for the SSRL microwave gun. ``State-of-the-art`` microwave gun designs employ laser-driven photocathodes, providing excellent performance but with greater complexity and monetary costs. A thermionic microwave gun with a magnetic bunching system is comparable in cost and complexity to a conventional system, but provides performance that is orders of magnitude better. Simulations of the SSRL microwave gun predict a normalized RMS emittance at the gun exist of < 10 π • m_ec • μm for a beam consisting of approximately 50% of the particles emitted from the gun, and having a momentum spread ±10%. These emittances are for up to 5 x 10⁹e^- per bunch. Chromatic aberrations in the transport line between the gun and linear accelerator increase this to typically < 30 π • m_e • μm.

A high-brightness thermionic microwave electron gun

International Nuclear Information System (INIS)

Borland, M.

1991-02-01

In a collaborative effort by SSRL, AET Associates, and Varian Associates, a high-brightness microwave electron gun using a thermionic cathode has been designed, built, tested, and installed for use with the SSRL 150 MeV linear accelerator. This thesis discusses the physics behind the design and operation of the gun and associated systems, presenting predictions and experimental tests of the gun's performance. The microwave gun concept is of increasing interest due to its promise of providing higher-current, lower-emittance electron beams than possible from conventional, DC gun technology. In a DC guns, accelerating gradients are less than 8 MV/m, while those in a microwave gun can exceed 100 MV/m, providing much more rapid initial acceleration, thereby reducing the deleterious effects of space-charge. Microwave guns produce higher momentum beams than DC guns, thus lessening space-charge effects during subsequent beam transport. Typical DC guns produce kinetic energies of 80--400 KeV, compared to 2--3 MeV for the SSRL microwave gun. ''State-of-the-art'' microwave gun designs employ laser-driven photocathodes, providing excellent performance but with greater complexity and monetary costs. A thermionic microwave gun with a magnetic bunching system is comparable in cost and complexity to a conventional system, but provides performance that is orders of magnitude better. Simulations of the SSRL microwave gun predict a normalized RMS emittance at the gun exist of e c · μm for a beam consisting of approximately 50% of the particles emitted from the gun, and having a momentum spread ±10%. These emittances are for up to 5 x 10 9 e - per bunch. Chromatic aberrations in the transport line between the gun and linear accelerator increase this to typically e · μm

Simulation of diode electron source of PSTA latex EBM using OPERA-3D software

International Nuclear Information System (INIS)

Taufik; Darsono

2014-01-01

Electron beam transport from E-gun to the atmospheres in EBM is determined by main parameters of beam transports such as E-gun, accelerator tube, beam optics (focusing and scanning magnets). In principle the beam transport will optimum if the electron beam travels in axial axes of accelerator tubes, and the beam optics works properly. The EBM E-gun structure of PSTA uses diode type with Pierce cathode where beam transport yield will be affected by electrode voltage of the accelerator tube. To answer above hypothesis the E-gun and accelerator tube will be simulated by making a model used accelerator software programme which is called OPERA-3D. Beam transport parameters, such as distance between cathode and anode of E-gun, accelerator electrode HV, and the symmetry of cathode Pierce E-gun with anode electrode of accelerator tube, will be investigated their impacts to direction and shape of beam transports. The simulation results shows that the three parameters affects to the direction and shape of the beam transport. Diode type of electron gun cannot result parallel electron beam, but the best beam transport of this type electron gun are obtained at the accelerator voltage 300 kV, and the distance between cathode and anode of E-gun 6.1 mm where they are in the symmetry condition. (author)

A high voltage test stand for electron gun qualification for LINACs

International Nuclear Information System (INIS)

Wanmode, Yashwant D.; Mulchandani, J.; Acharya, M.; Bhisikar, A.; Singh, H.G.; Shrivastava, Purushottam

2011-01-01

An electron gun lest stand has been developed at RRCAT. The test stand consists of a high voltage pulsed power supply, electron gun filament supply, grid supply, UHV system and electron gun current measurement system. Several electron guns developed indigenously were evaluated on this test stand. The shielding is provided for the electron gun set up. Electron gun tests can be tested upto 55 kV with pulse width of 15 microsecs and pulse repetition rates up to 200 Hz. The technical details of the subsystems are furnished and results of performance of the test stand have been reported in this paper. (author)

Advances in DC photocathode electron guns

International Nuclear Information System (INIS)

Dunham, B.M.; Hartmann, P.; Kazimi, R.; Liu, H.; Poelker, B.M.; Price, J.S.; Rutt, P.M.; Schneider, W.J.; Sinclair, C.K.

1999-01-01

At Jefferson Lab, a DC photoemission gun using GaAs and GaAs-like cathodes provides a source of polarized electrons for the main accelerator. The gun is required to produce high average current with long operational lifetimes and high system throughput. Recent work has shown that careful control of the parameters affecting cathode lifetime lead to dramatic improvements in source operation. These conditions include vacuum and the related effect of ion backbombardment, and precise control of all of the electrons emitted from the cathode. In this paper, we will review recent results and discuss implications for future photocathode guns. copyright 1999 American Institute of Physics

Development of beam diagnostic devices for characterizing electron guns

International Nuclear Information System (INIS)

Bhattacharjee, D.; Tiwari, R.; Jayaprakash, D.; Mishra, R.L.; Sarukte, H.; Waghmare, A.; Thakur, N.; Dixit, K.P.

2015-01-01

The electron guns for the DC accelerators and RF Linacs are designed and developed at EBC/APPD/BARC, Kharghar. These electron guns need to be characterized for its design and performance. Two test benches were developed for characterizing the electron guns. Various beam diagnostic devices for measuring beam currents and beam sizes were developed. Conical faraday cup, segmented faraday cup, slit scanning bellows movement arrangement, multi-plate beam size measurement setup, multi- wire beam size measurement setup, Aluminum foil puncture assembly etc. were developed and used. The paper presents the in-house development of various beam diagnostics for characterizing electron guns and their use. (author)

Development of laser heated high current DC electron gun

International Nuclear Information System (INIS)

Banerjee, Srutarshi; Bhattacharjee, Dhruva; Kandaswamy, E.; Ghodke, S.R.; Tiwari, Rajnish; Bakhtsingh, R.I.

2015-01-01

The paper deals with the development of a Laser heated cathode for Electron Accelerator. The electron gun is meant for Megawatt-class DC Accelerator for Electron Beam Flue Gas Treatment applications. Conventionally, LaB 6 cathode is indirectly heated by tungsten filaments whereas in the newly proposed gun, Laser is utilized for heating. A Nd:YAG Laser is used to heat the LaB 6 cathode to emission temperatures. The characterization of cathode heating at various Laser powers has been carried out. In initial trials, it has been observed that with 125 W of Laser power, the LaB 6 pellet was heated to 1315 ° C. Based on these experimental results, an electron gun rated for 30 kV, 350 mA CW has been designed. The optimization of gun electrode geometry has been done using CST Particle Studio in order to tune the various electron gun parameters. The beam diameter obtained in simulation is 8 mm at 100 mm from the LaB 6 cathode. The perveance obtained is 7.1 x 10 -8 A/V 3/2 . The Laser heated cathode has the advantages of eliminating the magnetic field effects of filament on the electron beam, electrical isolation needed for gun filament power supplies and better electron beam emittances. (author)

Performance of photocathode rf gun electron accelerators

International Nuclear Information System (INIS)

Ben-Zvi, I.

1993-01-01

In Photo-Injectors (PI) electron guns, electrons are emitted from a photocathode by a short laser pulse and then accelerated by intense rf fields in a resonant cavity. The best known advantage of this technique is the high peak current with a good emittance (high brightness). This is important for short wavelength Free-Electron Lasers and linear colliders. PIs are in operation in many electron accelerator facilities and a large number of new guns are under construction. Some applications have emerged, providing, for example, very high pulse charges. PIs have been operated over a wide range of frequencies, from 144 to 3000 MHz (a 17 GHz gun is being developed). An exciting new possibility is the development of superconducting PIs. A significant body of experimental and theoretical work exists by now, indicating the criticality of the accelerator elements that follow the gun for the preservation of the PI's performance as well as possible avenues of improvements in brightness. Considerable research is being done on the laser and photocathode material of the PI, and improvement is expected in this area

Performance of a carbon nanotube field emission electron gun

Science.gov (United States)

Getty, Stephanie A.; King, Todd T.; Bis, Rachael A.; Jones, Hollis H.; Herrero, Federico; Lynch, Bernard A.; Roman, Patrick; Mahaffy, Paul

2007-04-01

A cold cathode field emission electron gun (e-gun) based on a patterned carbon nanotube (CNT) film has been fabricated for use in a miniaturized reflectron time-of-flight mass spectrometer (RTOF MS), with future applications in other charged particle spectrometers, and performance of the CNT e-gun has been evaluated. A thermionic electron gun has also been fabricated and evaluated in parallel and its performance is used as a benchmark in the evaluation of our CNT e-gun. Implications for future improvements and integration into the RTOF MS are discussed.

Technological guns which form the profiled electron beans

International Nuclear Information System (INIS)

Mel'nik, V.I.

1998-01-01

Electron guns with high-voltage glow discharge are developed which form disc - and tubule-like,hollow conic and linear electron beams,as well as devices and systems for control of gun parameter and technological processes in low and intermediate vacuum

A 20 keV electron gun system for the electron irradiation experiments

International Nuclear Information System (INIS)

Mahapatra, S.K.; Dhole, S.D.; Bhoraskar, V.N.

2005-01-01

An electron gun consisting of cathode, focusing electrode, control electrode and anode has been designed and fabricated for the electron irradiation experiments. This electron gun can provide electrons of any energy over the range 1-20 keV, with current upto 50 μA. This electron gun and a Faraday cup are mounted in the cylindrical chamber. The samples are fixed on the Faraday cup and irradiated with electrons at a pressure ∼10 -7 mbar. The special features of this electron gun system are that, at any electron energy above 1 keV, the electron beam diameter can be varied from 5 to 120 mm on the Faraday cup mounted at a distance of 200 mm from the anode in the chamber. The variation in the electron current over the beam spot of 120 mm diameter is less than 15% and the beam current stability is better than 5%. This system is being used for studying the irradiation effects of 1-20 keV energy electrons on the space quality materials in which the irradiation time may vary from a few tens of seconds to hours

A 20 keV electron gun system for the electron irradiation experiments

Energy Technology Data Exchange (ETDEWEB)

Mahapatra, S.K. [Department of Physics, University of Pune, Pune 411007 (India); Dhole, S.D. [Department of Physics, University of Pune, Pune 411007 (India); Bhoraskar, V.N. [Department of Physics, University of Pune, Pune 411007 (India)]. E-mail: vnb@physics.unipune.ernet.in

2005-01-01

An electron gun consisting of cathode, focusing electrode, control electrode and anode has been designed and fabricated for the electron irradiation experiments. This electron gun can provide electrons of any energy over the range 1-20 keV, with current upto 50 {mu}A. This electron gun and a Faraday cup are mounted in the cylindrical chamber. The samples are fixed on the Faraday cup and irradiated with electrons at a pressure {approx}10{sup -7} mbar. The special features of this electron gun system are that, at any electron energy above 1 keV, the electron beam diameter can be varied from 5 to 120 mm on the Faraday cup mounted at a distance of 200 mm from the anode in the chamber. The variation in the electron current over the beam spot of 120 mm diameter is less than 15% and the beam current stability is better than 5%. This system is being used for studying the irradiation effects of 1-20 keV energy electrons on the space quality materials in which the irradiation time may vary from a few tens of seconds to hours.

Formation of a high quality electron beam using photo cathode RF electron gun

International Nuclear Information System (INIS)

Washio, Masakazu

2000-01-01

Formation of a high quality electron beam using photo cathode RF electron gun is expected for formation of a next generation high brilliant X-ray beam and a source for electron and positron collider. And, on a field of material science, as is possible to carry out an experiment under ultra short pulse and extremely high precision in time, it collects large expectation. Recently, formation of high quality beam possible to develop for multi directions and to use by everyone in future has been able to realize. Here were explained on electron beam source, principle and component on RF electron gun, working features on RF gun, features and simulation of RF gun under operation, and some views in near future. (G.K.)

Self-bunching electron guns

Science.gov (United States)

Mako, Frederick M.; Len, L. K.

1999-05-01

We report on three electron gun projects that are aimed at power tube and injector applications. The purpose of the work is to develop robust electron guns which produce self-bunched, high-current-density beams. We have demonstrated, in a microwave cavity, self-bunching, cold electron emission, long life, and tolerance to contamination. The cold process is based on secondary electron emission. FMT has studied using simulation codes the resonant bunching process which gives rise to high current densities (0.01-5 kA/cm2), high charge bunches (up to 500 nC/bunch), and short pulses (1-100 ps) for frequencies from 1 to 12 GHz. The beam pulse width is nominally ˜5% of the rf period. The first project is the L-Band Micro-Pulse Gun (MPG). Measurements show ˜40 ps long micro-bunches at ˜20 A/cm2 without contamination due to air exposure. Lifetime testing has been carried out for about 18 months operating at 1.25 GHz for almost 24 hours per day at a repetition rate of 300 Hz and 5 μs-long macro-pulses. Approximately 5.8×1013 micro-bunches or 62,000 coulombs have passed through this gun and it is still working fine. The second project, the S-Band MPG, is now operational. It is functioning at a frequency of 2.85 GHz, a repetition rate of 30 Hz, with a 2 μs-long macro-pulse. It produces about 45 A in the macro-pulse. The third project is a 34.2 GHz frequency-multiplied source driven by an X-Band MPG. A point design was performed at an rf output power of 150 MW at 34.2 GHz. The resulting system efficiency is 53% and the gain is 60 dB. The system efficiency includes the input cavity efficiency, input driver efficiency (a 50 MW klystron at 11.4 GHz), output cavity efficiency, and the post-acceleration efficiency.

Development of an electron gun for high power CW electron linac

International Nuclear Information System (INIS)

Yamazaki, Yoshio; Nomura, Masahiro

1994-01-01

An electron gun launching high average current beam has been designed for the high power CW electron linac at PNC. A peak electron beam current of 400mA with beam energy 200keV is required from the buncher design. However its average current is very high(duty factor 20%), a mesh grid is not able to be used for current control because of heating up or melting of grid. Furthermore, the beam current have to be variable up to 400mA to match with downstream modules, especially the accelerating guides including recirculating system. We employed the electron gun with two aperture grids to control beam current. The dimension of the electrodes, electron trajectory, the size of beam radius, and gun emittance was simulated by EGUN. (author)

The structural design and the electron optics of a hybrid electron-ion gun

International Nuclear Information System (INIS)

Bas, E.B.; Gisler, E.; Stucki, F.

1984-01-01

This paper describes a new kind of a particle gun called the hybrid gun. It is able to deliver a finely focused electron or ion beam simply by reversing the polarity of the acceleration voltage. The detailed design features of the gun are given and the electron-ion optical properties are discussed. (author)

Low-energy plasma-cathode electron gun with a perforated emission electrode

Science.gov (United States)

Burdovitsin, Victor; Kazakov, Andrey; Medovnik, Alexander; Oks, Efim; Tyunkov, Andrey

2017-11-01

We describe research of influence of the geometric parameters of perforated electrode on emission parameters of a plasma cathode electron gun generating continuous electron beams at gas pressure 5-6 Pa. It is shown, that the emission current increases with increasing the hole diameters and decreasing the thickness of the perforated emission electrode. Plasma-cathode gun with perforated electron can provide electron extraction with an efficiency of up to 72 %. It is shown, that the current-voltage characteristic of the electron gun with a perforated emission electrode differs from that of similar guns with fine mesh grid electrode. The plasma-cathode electron gun with perforated emission electrode is used for electron beam welding and sintering.

To the theory of the Pierce instability of neutralized electron flows

International Nuclear Information System (INIS)

Ignatov, A.M.; Rukhadze, A.A.

1984-01-01

The Pierce instability of a nonrelativistic electron beam in an exernal fi inite magnetic field is investigated. Analytical expressions for a critical electron density in limiting cases of strong or weak magnetic field have been fo ound. The critical electron density is shown to increase with a decrease in the magnetic field strength

Plural beam electron gun assembly

International Nuclear Information System (INIS)

Stratton, M.G.

1977-01-01

The invention relates to a cathode ray tube plural-beam-in-line bi-potential electron gun assembly, having applied beam currents of differing levels, manifests structurally modified gun structures to effect focused beam landings at the screen that are evidenced as substantially equi-sized spots thereby providing improved resolution and brightness of the screen imagery. The structural changes embody modifications of the related focusing and accelerator electrodes of the respective guns to provide a partial telescoping arrangement for effecting the discrete placement, forming and shielding of the final focusing lenses. The three lenses so formed are in different planes in partial overlapping axial relationship

Modular Low-Heater-Power Cathode/Electron Gun Assembly for Microwave and Millimeter Wave Traveling Wave Tubes

Science.gov (United States)

Wintucky, Edwin G.

2000-01-01

cathode/electron gun assembly consists of four subassemblies the cathode, the focus electrode, the header (including the electrical feedthroughs), and the gun envelope (including the anode) a diagram of which is shown. The modular construction offers a number of significant advantages, including flexibility of design, interchangeability of parts, and a drop-in final assembly procedure for quick and accurate alignment. The gun can accommodate cathodes ranging in size from 0.050 to 0.250-in. in diameter and is applicable to TWT's over a broad range of sizes and operating parameters, requiring the substitution of only a few parts: that is, the cathode, focus electrode, and anode. The die-pressed cathode pellets can be made with either flat or concave (Pierce gun design) emitting surfaces. The gun can be either gridded (pulse operation) or ungridded (continuous operation). Important factors contributing to low cost are the greater use of CRT materials and parts, the standardization of processes (welding and mechanical capture), and tooling amenable to automated production. Examples are the use of simple shapes, drawn or stamped metal parts, and parts joined by welding or mechanical capture. Feasibility was successfully demonstrated in the retrofit and testing of a commercial Kaband (22-GHz) TWT. The modular cathode/electron gun assembly was computer modeled to replicate the performance of the original electron gun and fabricated largely from existing CRT parts. Significant test results included demonstration of low heater power (1.5-W, 1010 C brightness temperature for a 0.085-in.-diameter cathode), mechanical ruggedness (100g shock and vibration tests in accordance with military specifications (MIL specs)), and a very fast warmup. The results of these tests indicate that the low-cost CRT manufacturing approach can be used without sacrificing performance and reliability.

Study of the hollow cathode plasma electron-gun

International Nuclear Information System (INIS)

Zhang Yonghui; Jiang Jinsheng; Chang Anbi

2003-01-01

For developing a novel high-current, long pulse width electron source, the theoretics and mechanism of the hollow cathode plasma electron-gun are analyzed in detail in this paper, the structure and the physical process of hollow cathode plasma electron-gun are also studied. This gun overcomes the limitations of most high-power microwave tubes, which employ either thermionic cathodes that produce low current-density beams because of the limitation of the space charge, or field-emission cathodes that offer high current density but provide only short pulse width because of plasma closure of the accelerating gap. In the theories studying on hollow cathode plasma electron-gun, the characteristic of the hollow-cathode discharge is introduced, the action during the forming of plasma of the stimulating electrode and the modulating anode are discussed, the movement of electrons and ions and the primary parameters are analyzed, and the formulas of the electric field, beam current density and the stabilization conditions of the beam current are also presented in this paper. The numerical simulation is carried out based on Poisson's equation, and the equations of current continuity and movement. And the optimized result is reported. On this basis, we have designed a hollow-cathode-plasma electron-gun, whose output pulse current is 2 kA, and pulse width is 1 microsecond

Performance of the Antares large area cold cathode electron gun

International Nuclear Information System (INIS)

Rosocha, L.A.; Mansfield, C.R.

1983-01-01

The performance of the electron gun which supplies ionization for the Antares high power electron beam sustained CO 2 laser power amplifier is described. This electron gun is a coaxial cylindrical cold cathode vacuum triode having a total electron aperture area of approximately 9 m 2 . Electrons are extracted from the gun in pulses of 3-6 μs duration, average current densities of 40-60 ma/cm2, and electron energies of 450-500 keV. The main areas of discussion in this paper are the performance in terms of grid control, current density balance, and current runaway due to breakdown limitations. Comparison of the experimental results with the predictions of a theoretical model for the electron gun will also be presented

Performance of the Antares large area cold cathode electron gun

International Nuclear Information System (INIS)

Rosocha, L.A.; Mansfield, C.R.

1983-01-01

The performance of the electron gun which supplies ionization for the Antares high-power electron-beam-sustained CO 2 -laser power amplifier is described. This electron gun is a coaxial cylindrical cold cathode vacuum triode having a total electron aperture area of approximately 9 m 2 . Electrons are extracted from the gun in pulses of 3 to 6 μs duration, average current densities of 40 to 60 mA/cm 2 , and electron energies of 450 to 500 keV. The main areas of discussion in this paper are the performance in terms of grid control, current-density balance, and current runaway due to breakdown limitations. Comparison of the experimental results with the predictions of a theoretical model for the electron gun are also presented

Enhanced ECR ion source performance with an electron gun

International Nuclear Information System (INIS)

Xie, Z.; Lyneis, C.M.; Lam, R.S.; Lundgren, S.A.

1991-01-01

An electron gun for the advanced electron cyclotron resonance (AECR) source has been developed to increase the production of high charge state ions. The AECR source, which operates at 14 GHz, is being developed for the 88-in. cyclotron at Lawrence Berkeley Laboratory. The electron gun injects 10 to 150 eV electrons into the plasma chamber of the AECR. With the electron gun the AECR has produced at 10 kV extraction voltage 131 e μA of O 7+ , 13 e μA of O 8+ , 17 e μA of Ar 14+ , 2.2 e μA of Kr 25+ , 1 e μA of Xe 31+ , and 0.2 e μA of Bi 38+ . The AECR was also tested as a single stage source with a coating of SiO 2 on the plasma chamber walls. This significantly improved its performance compared to no coating, but direct injection of electrons with the electron gun produced the best results

Research and design of electron gun of electrocurtain

International Nuclear Information System (INIS)

Chen Pengfei; Zhang Mingchao; Li Xinmin; Wang Yuhong

1998-01-01

The characteristics of the electron beam current transport in the electron gun of the electrocurtain accelerator were studied and the origin of the influence on longitudinal uniformity of beam current was analysed. The deflection of the cathode is considered under the boundary condition of perfect constraint. Then a newly designed electron gun is introduced with longitudinal uniformity of current within +-10%

New Electron Gun System for BEPCII

CERN Document Server

Liu, Bo; Long Chi, Yun; Zhang, Chuang

2005-01-01

The new electron gun system for BEPCII has been put into operation since Nov. 2004. The article describes the design, experiment and operation of this new system. The design current of the gun is 10 A for the pulse lengths of 1 ns, 2.5 ns and 1 μs with repetition rate of 50 Hz. The gun is operated with a pulsed high voltage power supply which can provide up to 200 kV high voltage. Computer simulations have been carried out in the design stage, including simulation of the gun geometry and beam transportation. Some important relation curves are obtained during the experiment. Two-bunch operation is available and some elementary tests have been performed. New scheme of the gun control system based on EPICS is also presented. The real operation shows that the design and manufacturing is basically successful.

rf traveling-wave electron gun for photoinjectors

Science.gov (United States)

Schaer, Mattia; Citterio, Alessandro; Craievich, Paolo; Reiche, Sven; Stingelin, Lukas; Zennaro, Riccardo

2016-07-01

The design of a photoinjector, in particular that of the electron source, is of central importance for free electron laser (FEL) machines where a high beam brightness is required. In comparison to standard designs, an rf traveling-wave photocathode gun can provide a more rigid beam with a higher brightness and a shorter pulse. This is illustrated by applying a specific optimization procedure to the SwissFEL photoinjector, for which a brightness improvement up to a factor 3 could be achieved together with a double gun output energy compared to the reference setup foreseeing a state-of-the-art S-band rf standing-wave gun. The higher brightness is mainly given by a (at least) double peak current at the exit of the gun which brings benefits for both the beam dynamics in the linac and the efficiency of the FEL process. The gun design foresees an innovative coaxial rf coupling at both ends of the structure which allows a solenoid with integrated bucking coil to be placed around the cathode in order to provide the necessary focusing right after emission.

High quality flux control system for electron gun evaporation

International Nuclear Information System (INIS)

Appelbloom, A.M.; Hadley, P.; van der Marel, D.; Mooij, J.E.

1991-01-01

This paper reports on a high quality flux control system for electron gun evaporation developed and tested for the MBE growth of high temperature superconductors. The system can be applied to any electron gun without altering the electron gun itself. Essential elements of the system are a high bandwidth mass spectrometer, control electronics and a high voltage modulator to sweep the electron beam over the melt at high frequencies. the sweep amplitude of the electron beam is used to control the evaporation flux at high frequencies. The feedback loop of the system has a bandwidth of over 100 Hz, which makes it possible to grow superlattices and layered structures in a fast and precisely controlled manner

Recent advances in high-brightness electron guns at AES

International Nuclear Information System (INIS)

Bluem, H.; Todd, A.M.M.; Cole, M.D.; Rathke, J.; Schultheiss, T.

2003-01-01

We describe a number of active Advanced Energy Systems projects pertaining to the development of advanced, high-brightness electron guns for various applications. These projects include a fully superconducting, CW RF gun, nearing test, that utilizes the niobium surface as the photocathode material. An integrated 100 mA, low emittance DC/SRF gun, ideal as an injector for ERL-type light sources and intended as the injector for a 100 kW FEL, is in late design stage. A parallel high-power, CW, normal-conducting L-band RF gun project has just begun. The early performance analysis for this gun also shows good promise as an injector for ERL-type light sources. Lastly, a fully axisymmetric RF gun, operating in X-band, is being studied as a source of extremely bright electron bunches

DC photoemission electron guns as ERL sources

International Nuclear Information System (INIS)

Sinclair, Charles K.

2006-01-01

Very-high-voltage DC electron guns, delivering moderate duration bunches from photoemission cathodes, and followed by conventional drift bunching and acceleration, offer a practical solution for an ERL injector. In a variant of this scheme, a DC gun is placed in close proximity to a superconducting RF accelerator cavity, with few or no active elements between the gun and cavity. The principal technical challenge with such electron guns arises from field emission from the cathode electrode and its support structure. Field emission may result in voltage breakdown across the cathode-anode gap, or a punch-through failure of the insulator holding off the cathode potential, as well as lesser though still serious problems. Various means to mitigate these problems are described. The operational lifetime of high quantum efficiency photocathodes in these guns is determined by the vacuum conditions, through phenomena such as chemical poisoning and ion back-bombardment. Minimization of the field strength on electrode structures pushes high-voltage DC guns toward large dimensions and, correspondingly, large outgassing loads, but it is also true that these guns offer many opportunities for achieving excellent vacuum conditions. Good solutions to vacuum problems that had previously limited cathode lifetime have been demonstrated in recent years. Designs for DC guns presently in use and planned for the near future will be described. The parameters necessary for a 100 mA average current, very-high-voltage DC gun with a photocathode operational lifetime greater than 100 h appear to be within reach, but have yet to be demonstrated. A 1 A average current source with good cathode operational lifetime will require developments beyond the present state-of-the-art

One nanosecond pulsed electron gun systems

International Nuclear Information System (INIS)

Koontz, R.F.

1979-02-01

At SLAC there has been a continuous need for the injection of very short bunches of electrons into the accelerator. Several time-of-flight experiments have used bursts of short pulses during a normal 1.6 micro-second rf acceleration period. Single bunch beam loading experiments made use of a short pulse injection system which included high power transverse beam chopping equipment. Until the equipment described in this paper came on line, the basic grid-controlled gun pulse was limited to a rise time of 7 nanoseconds and a pulse width of 10 nanoseconds. The system described here has a grid-controlled rise time of less than 500 pico-seconds, and a minimum pulse width of less than 1 nanosecond. Pulse burst repetition rate has been demonstrated above 20 MHz during a 1.6 microsecond rf accelerating period. The order-of-magnitude increase in gun grid switching speed comes from a new gun design which minimizes lead inductance and stray capacitance, and also increases gun grid transconductance. These gun improvements coupled with a newly designed fast pulser mounted directly within the gun envelope make possible subnanosecond pulsing of the gun

Preparation of targets using electron gun systems

International Nuclear Information System (INIS)

Maier-Komor, P.

1975-01-01

Most targets of isotopes with very low vapor pressure can only be fabricated by vacuum deposition using an electron gun system or a heavy ion sputtering system. Heavy ion sputtering is a very new technique with many unsolved problems. Therefore it seems to be easier to work with an electron gun. Different commercially available electron guns, which are all designed for the high evaporation rates used in industry, are examined for their qualification in processing small amounts of material as used in fabrication of isotope targets. Electron backscattering and the associated efficiency of the electron beam power is strongly dependent on the atomic number Z of the evaporant and the incident angle of the electron beam on the surface of the evaporant. This dependence leads also to the undesired effects to the target layers from electrons and ions. Some precautions are necessary against the effects of the electrons and ions, which are formed in the plasma directly over the beam impact point. Beam power and beam density have to be chosen to get a constant evaporation rate and a low enough condensation rate in order not to overheat the target substrates. To evaporate some metals it may be helpful to pulse the electron beam

Finite element analyses of a linear-accelerator electron gun

Science.gov (United States)

Iqbal, M.; Wasy, A.; Islam, G. U.; Zhou, Z.

2014-02-01

Thermo-structural analyses of the Beijing Electron-Positron Collider (BEPCII) linear-accelerator, electron gun, were performed for the gun operating with the cathode at 1000 °C. The gun was modeled in computer aided three-dimensional interactive application for finite element analyses through ANSYS workbench. This was followed by simulations using the SLAC electron beam trajectory program EGUN for beam optics analyses. The simulations were compared with experimental results of the assembly to verify its beam parameters under the same boundary conditions. Simulation and test results were found to be in good agreement and hence confirmed the design parameters under the defined operating temperature. The gun is operating continuously since commissioning without any thermal induced failures for the BEPCII linear accelerator.

Finite element analyses of a linear-accelerator electron gun

Energy Technology Data Exchange (ETDEWEB)

Iqbal, M., E-mail: muniqbal.chep@pu.edu.pk, E-mail: muniqbal@ihep.ac.cn [Centre for High Energy Physics, University of the Punjab, Lahore 45590 (Pakistan); Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Wasy, A. [Department of Mechanical Engineering, Changwon National University, Changwon 641773 (Korea, Republic of); Islam, G. U. [Centre for High Energy Physics, University of the Punjab, Lahore 45590 (Pakistan); Zhou, Z. [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

2014-02-15

Thermo-structural analyses of the Beijing Electron-Positron Collider (BEPCII) linear-accelerator, electron gun, were performed for the gun operating with the cathode at 1000 °C. The gun was modeled in computer aided three-dimensional interactive application for finite element analyses through ANSYS workbench. This was followed by simulations using the SLAC electron beam trajectory program EGUN for beam optics analyses. The simulations were compared with experimental results of the assembly to verify its beam parameters under the same boundary conditions. Simulation and test results were found to be in good agreement and hence confirmed the design parameters under the defined operating temperature. The gun is operating continuously since commissioning without any thermal induced failures for the BEPCII linear accelerator.

Finite element analyses of a linear-accelerator electron gun

International Nuclear Information System (INIS)

Iqbal, M.; Wasy, A.; Islam, G. U.; Zhou, Z.

2014-01-01

Thermo-structural analyses of the Beijing Electron-Positron Collider (BEPCII) linear-accelerator, electron gun, were performed for the gun operating with the cathode at 1000 °C. The gun was modeled in computer aided three-dimensional interactive application for finite element analyses through ANSYS workbench. This was followed by simulations using the SLAC electron beam trajectory program EGUN for beam optics analyses. The simulations were compared with experimental results of the assembly to verify its beam parameters under the same boundary conditions. Simulation and test results were found to be in good agreement and hence confirmed the design parameters under the defined operating temperature. The gun is operating continuously since commissioning without any thermal induced failures for the BEPCII linear accelerator

Characteristics of electron gun used in the accelerator for customs inspection systems

International Nuclear Information System (INIS)

Huang Weiling; Li Quanfeng; Zhang Yunkai

2001-01-01

The author introduces the characteristics of the electron gun used in the 9 MeV traveling wave electron linear accelerator for fixed customs container inspection system. With the scan date cathode, the electron gun meets the accelerator characteristics with the whole system not needing high-temperature roasting to degas. The electron gun can work normally at a vacuum of about 10 -5 Pa and can be reinstalled after exposure to air. In the accelerator, the electron gun emits a beam which strikes the target to produce an X-ray beam with a dosage rate of over 30 Gy/(min·m) and a beam focus spot of less than φ 2 mm. The EGUN code is used to simulate the structure and properties of the electron gun. The reference size debugging parameters for replacing the electron gun are given for assembly requirements

A novel electron gun for inline MRI-linac configurations

International Nuclear Information System (INIS)

Constantin, Dragoş E.; Fahrig, Rebecca; Holloway, Lois; Keall, Paul J.

2014-01-01

Purpose: This work introduces a new electron gun geometry capable of robust functioning in the presence of a high strength external magnetic field for axisymmetric magnetic resonance imaging (MRI)-linac configurations. This allows an inline MRI-linac to operate without the need to isolate the linear accelerator (linac) using a magnetic shield. This MRI-linac integration approach not only leaves the magnet homogeneity unchanged but also provides the linac flexibility to move along the magnet axis of symmetry if the source to target distance needs to be adjusted. Methods: Simple electron gun geometry modifications of a Varian 600C electron gun are considered and solved in the presence of an external magnetic field in order to determine a set of design principles for the new geometry. Based on these results, a new gun geometry is proposed and optimized in the fringe field of a 0.5 T open bore MRI magnet (GE Signa SP). A computer model for the 6 MeV Varian 600C linac is used to determine the capture efficiency of the new electron gun-linac system in the presence of the fringe field of the same MRI scanner. The behavior of the new electron gun plus the linac system is also studied in the fringe fields of two other magnets, a 1.0 T prototype open bore magnet and a 1.5 T GE Conquest scanner. Results: Simple geometrical modifications of the original electron gun geometry do not provide feasible solutions. However, these tests show that a smaller transverse cathode diameter with a flat surface and a slightly larger anode diameter could alleviate the current loss due to beam interactions with the anode in the presence of magnetic fields. Based on these findings, an initial geometry resembling a parallel plate capacitor with a hole in the anode is proposed. The optimization procedure finds a cathode-anode distance of 5 mm, a focusing electrode angle of 5°, and an anode drift tube length of 17.1 mm. Also, the linac can be displaced with ±15 cm along the axis of the 0.5 T

Laser-pulsed relativistic electron gun

International Nuclear Information System (INIS)

Sherman, N.K.

1986-01-01

A relativistic (β ≅ 0.8) electron gun with good emittance and subnanosecond pulse duration which can be synchronized to picosecond laser pulses is being developed at NRC for use in studies of particle acceleration by lasers. Bursts of electron pulses exceeding 280 keV in energy have been extracted into air form a laser-driven vacuum photodiode. Trains of 5 ps pulses of ultraviolet UV light illuminate a magnesium cathode. Photoelectrons emitted from the cathode are accelerated in a graded electrostatic potential set up by a 360 kV Marx-generator. The UV pulses are obtained by doubling the frequency of a 606 nm dye laser modelocked at 160 MHz. Electron energies were measured by residual range in an echelon of Al foils. Total charge per burst was measured by picoammeter. Time structure of the bursts has been examined with plastic scintillator and a fast photomultiplier. Tests on a low voltage photodiode achieved a current density of 180 A/cm/sup 2/ from an Mg cathode, with quantum efficiency of 2.4 x 10/sup -6/ electron per UV photon. The brevity and intensity of the laser pulses cause the electric charge collected per pulse to increase linearly with bias voltage rather than according to the Langmuir-Child law. Gun emittance is about 150 mm-msr and beam brightness is about 1A/cm/sup 2/-sr. Estimated duration of individual electron pulses of a burst is about 400 ps with instantaneous current of about 0.1 mA. Energy spread within one pulse is expected to be about 15%. This gun has the potential to be a useful source of relativistic electrons for laser acceleration studies

Measurement of electron beams profile of pierce type electron source using sensor of used Tv tube

International Nuclear Information System (INIS)

Darsono; Suhartono; Suprapto; Elin Nuraini

2015-01-01

The measurement of an electron beam profile has been performed using electron beam monitor based on method of phosphorescent materials. The main components of the electron beam monitor consists of a fluorescent sensor using a used Tv tube, CCTV camera to record images on a Tv screen, video adapter as interface between CCTV and laptop, and the laptop as a viewer and data processing. Two Pierce-type electron sources diode and triode was measured the shape of electron beam profile in real time. Results of the experiments showed that the triode electron source of Pierce type gave the shape of electron beam profiles better than that of the diode electron source .The anode voltage is not so influential on the beam profile shape. The focused voltage in the triode electron source is so influence to the shape of the electron beam profile, but above 5 kV no great effect. It can be concluded that the electron beam monitor can provide real time observations and drawings shape of the electron beam profile displayed on the used Tv tube glass screen which is the real picture of the shape of the electron beam profile. Triode electron source produces a better electron beam profile than that of the diode electron source. (author)

Performance review of thermionic electron gun developed for RF linear accelerators at RRCAT

International Nuclear Information System (INIS)

Wanmode, Yashwant; Mulchandani, J.; Reddy, T.S.; Bhisikar, A.; Singh, H.G.; Shrivastava, Purushottam

2015-01-01

RRCAT is engaged in development of RF electron linear accelerator for irradiation of industrial and agricultural products. Thermionic electron gun is primary source for this accelerator as beam current in the RF accelerator is modest and thermionic emission is most prevalent option for electron gun development. An electron gun has to meet high cathode emission capability, low filament power, good accessibility for cathode replacement and should provide short time for maintenance. Electron linear accelerator up to beam energy of 10 MeV require electron source of 45-50 keV beam energy and emission current of 1 A. Electron optics of gun and electron beam profile simulations were carried out using CST's particle tracking code and EGUN code. Triode type electron gun of cathode voltage 50 kV pulsed has been designed, developed and integrated with 10 MeV electron linear accelerators at RRCAT. Beam current of more than 600 mA has been measured with faraday cup in the test stand developed for characterizing the electron gun. Two accelerators one is imported and another one developed indigenously has been energized using this electron gun. Beam energy of 5-10 MeV has been achieved with beam current of 250-400 mA by integrating this electron gun with the linear accelerator. This paper reviews the performance of indigenously developed electron gun for both linear accelerators. (author)

rf traveling-wave electron gun for photoinjectors

Directory of Open Access Journals (Sweden)

Mattia Schaer

2016-07-01

Full Text Available The design of a photoinjector, in particular that of the electron source, is of central importance for free electron laser (FEL machines where a high beam brightness is required. In comparison to standard designs, an rf traveling-wave photocathode gun can provide a more rigid beam with a higher brightness and a shorter pulse. This is illustrated by applying a specific optimization procedure to the SwissFEL photoinjector, for which a brightness improvement up to a factor 3 could be achieved together with a double gun output energy compared to the reference setup foreseeing a state-of-the-art S-band rf standing-wave gun. The higher brightness is mainly given by a (at least double peak current at the exit of the gun which brings benefits for both the beam dynamics in the linac and the efficiency of the FEL process. The gun design foresees an innovative coaxial rf coupling at both ends of the structure which allows a solenoid with integrated bucking coil to be placed around the cathode in order to provide the necessary focusing right after emission.

Secondary emission electron gun using external primaries

Science.gov (United States)

Srinivasan-Rao, Triveni [Shoreham, NY; Ben-Zvi, Ilan [Setauket, NY

2009-10-13

An electron gun for generating an electron beam is provided, which includes a secondary emitter. The secondary emitter includes a non-contaminating negative-electron-affinity (NEA) material and emitting surface. The gun includes an accelerating region which accelerates the secondaries from the emitting surface. The secondaries are emitted in response to a primary beam generated external to the accelerating region. The accelerating region may include a superconducting radio frequency (RF) cavity, and the gun may be operated in a continuous wave (CW) mode. The secondary emitter includes hydrogenated diamond. A uniform electrically conductive layer is superposed on the emitter to replenish the extracted current, preventing charging of the emitter. An encapsulated secondary emission enhanced cathode device, useful in a superconducting RF cavity, includes a housing for maintaining vacuum, a cathode, e.g., a photocathode, and the non-contaminating NEA secondary emitter with the uniform electrically conductive layer superposed thereon.

A design study of non-adiabatic electron guns

International Nuclear Information System (INIS)

Barroso, J.J.; Stellati, C.

1994-01-01

The design of a non-adiabatic gun capable of producing a 10 A, 50 KeV high-quality laminar electron beam is reported. In contrast to the magnetron injection gun with a conical cathode, where the beam is generated initially with a transverse velocity component, in the non-adiabatic gun electrons are extracted in a direction parallel to the axial guide magnetic field. The beam electrons acquire cyclotron motion as result of non-adiabatic processes in a strong non uniform electric field across the modulation anode. Such an extraction method gives rise to favourable features that are explored throughout the work. An extensive numerical simulation study has also been done to minimize velocity and energy spreads. (author). 3 refs, 5 figs, 1 tab

Study and realization of an electron gun at low energy

International Nuclear Information System (INIS)

Camus, P.

1977-01-01

This work presents the theoretical concepts and experimental design of an electron gun. This gun is working in the weak energy range and the focus position is independant of electron energy measurements and analysis methods of the electron beam are described [fr

The structural design of an electron gun for an E-beam irradiator

International Nuclear Information System (INIS)

Yu Xiaojuan; Wu Xunlei; Jiang Zhenbo; Meng Mingfeng

2011-01-01

In this paper, an electron gun for a linac E-beam irradiator is developed with a replaceable cathode and filament. The structure of cathode and filament and the concentric technique, with molds and clamps, are described in detail. The electron gun was assembled with care to reduce the error, and ensure the concentricity of electron gun. The test results indicated a 99.99% pass ratio of the electron beams at 60-65 kV. The electron gun design meets the technical requirement of clients. (authors)

The polarized electron gun for the SLC

International Nuclear Information System (INIS)

Schultz, D.C.; Clendenin, J.; Frisch, J.; Hoyt, E.; Klaisner, L.; Woods, M.; Wright, D.; Zolotorev, M.

1992-03-01

A new polarized electron gun for use on the SLC at SLAC has been built and tested. It is a diode gun with a laser driven GaAs photocathode. It is designed to provide short (2ns) pulses of 10 A at 160 kV at 120 Hz. The design features of the gun and results from a testing program on a new and dedicated beam line are presented. Early results from operation on the SLC will also be shown

The Use of an Electron Microchannel as a Self-Extracting and Focusing Plasma Cathode Electron Gun

International Nuclear Information System (INIS)

Cornish, S.; Khachan, J.

2016-01-01

A new and simple type of electron gun is presented. Unlike conventional electron guns, which require a heated filament or extractor, accelerator and focusing electrodes, this gun uses the collimated electron microchannels of an inertial electrostatic confinement (IEC) discharge to achieve the same outcome. A cylindrical cathode is placed coaxially within a cylindrical anode to create the discharge. Collimated beams of electrons and fast neutrals emerge along the axis of the cylindrical cathode. This geometry isolates one of the microchannels that emerge in a negatively biased IEC grid. The internal operating pressure range of the gun is 35-190 mTorr. A small aperture separates the gun from the main vacuum chamber in order to achieve a pressure differential. The chamber was operated at pressures of 4-12 mTorr. The measured current produced by the gun was 0.1-3 mA (0.2-14 mA corrected measurement) for discharge currents of 1-45 mA and discharge voltages of 0.5-12 kV. The collimated electron beam emerges from the aperture into the vacuum chamber. The performance of the gun is unaffected by the pressure differential between the vacuum chamber and the gun. This allows the aperture to be removed and the chamber pressure to be equal to the gun pressure if required. (paper)

The Use of an Electron Microchannel as a Self-Extracting and Focusing Plasma Cathode Electron Gun

Science.gov (United States)

Cornish, S.; Khachan, J.

2016-02-01

A new and simple type of electron gun is presented. Unlike conventional electron guns, which require a heated filament or extractor, accelerator and focusing electrodes, this gun uses the collimated electron microchannels of an inertial electrostatic confinement (IEC) discharge to achieve the same outcome. A cylindrical cathode is placed coaxially within a cylindrical anode to create the discharge. Collimated beams of electrons and fast neutrals emerge along the axis of the cylindrical cathode. This geometry isolates one of the microchannels that emerge in a negatively biased IEC grid. The internal operating pressure range of the gun is 35-190 mTorr. A small aperture separates the gun from the main vacuum chamber in order to achieve a pressure differential. The chamber was operated at pressures of 4-12 mTorr. The measured current produced by the gun was 0.1-3 mA (0.2-14 mA corrected measurement) for discharge currents of 1-45 mA and discharge voltages of 0.5-12 kV. The collimated electron beam emerges from the aperture into the vacuum chamber. The performance of the gun is unaffected by the pressure differential between the vacuum chamber and the gun. This allows the aperture to be removed and the chamber pressure to be equal to the gun pressure if required.

Velocity Spread Reduction for Axis-encircling Electron Beam Generated by Single Magnetic Cusp

Science.gov (United States)

Jeon, S. G.; Baik, C. W.; Kim, D. H.; Park, G. S.; Sato, N.; Yokoo, K.

2001-10-01

Physical characteristics of an annular Pierce-type electron gun are investigated analytically. An annular electron gun is used in conjunction with a non-adiabatic magnetic reversal and an adiabatic compression to produce an axis-encircling electron beam. Velocity spread close to zero is realized with an initial canonical angular momentum spread at the cathode when the beam trajectory does not coincide with the magnetic flux line. Both the analytical calculation and the EGUN code simulation confirm this phenomenon.

Design studies on high current and grid control electron gun

International Nuclear Information System (INIS)

Wang Jinnan; Lu Kun; Chi Yunlong; Zhou Zusheng

2011-01-01

Electron gun, the source of electrons, is a kind of ultrahigh vacuum device and plays an important role in different kind of accelerators. With the irradiation accelerator demands, describes the design studies on beam optics optimization. The simulation result shows that the beam current is above 5 A with cathode voltage of 80 kV and beam emittance, gun electric field and beam waist radius meet the accelerator needs. The electron gun manufactured and installed in the test stand, the conditioning and test will be done in the near future. (authors)

Theoretical investigation of an electron gun with a point cathode

International Nuclear Information System (INIS)

Rauh, H.; Kern, D.

1978-01-01

Electron-optical properties of a gun with a point cathode are determined numerically by tracing a greater number of electron trajectories. In order to calculate the beam current density distribution, an attempt was made to describe the properties of the gun in terms of the parameters describing the inital conditions of the trajectories. Contrary to the conventional electron-optical imaging theory, the electron gun under consideration cannot be sufficiently characterized by a few aberration coefficients, since only a small fraction of the trajectories forming the electron beam would be covered by an expansion containing linear, third and fifth order terms so that the series expansion method is not applicable. (orig.) 891 WBU [de

Numerical modelling of the CEBAF electron gun with EGUN

International Nuclear Information System (INIS)

Liger, P.; Krafft, G.A.

1991-01-01

The electron source used in the injector for the CEBAF accelerator is a Hermosa electron gun with a 2 mm diameter cathode and a control electrode. It produces a 100 keV electron beam to be focused on the first of two apertures which comprise an emittance filter. A normalized emittance of less than π mm mrad at 1.2 mA is set by the requirements of the final beam from the CEBAF linac, since downstream of the filter, a system of two choppers and a third aperture removes 5/6 of the current. In addition, for RF test purposes a higher current of about 5 mA is needed, possibly at higher emittance. This paper presents a way of calculating the characteristics of the CEBAF electron gun with the gun design code EGUN, and the accuracy of the results is discussed. The transverse shape of the beam delivered by the gun has been observed, and its current measured. A halo around the beam has been seen, and the calculations can reproduce this effect

Supply system with microprocessor control for electron gun

International Nuclear Information System (INIS)

Duplin, N.I.; Sergeev, N.N.

1988-01-01

Precision supply system for electron gun used in Auger-spectrometer is described. The supply system consists of control and high-voltage parts, made as separate units. Supply high-voltage unit includes system supply module, filament module to supply electron gun cathode and 6 high-volt modules to supply accelerating, modulating and three focusing electrodes of the gun. High-voltage modules have the following characteristics: U-(100-1000)V output voltage, 5x10 -5 U stability, 10 -5 xU pulsation amplitude, J-(0-5)A filament current change range at 10 -4 xJ stability. Control unit including microprocessor, timer and storage devices forms control voltage for all modules and regulates voltage and current of filament at electrodes

Design, development and characterization of tetrode type electron gun system for generation of low energy electrons

International Nuclear Information System (INIS)

Deore, A.V.; Bhoraskar, V.N.; Dhole, S.D.

2011-01-01

A tetrode type electron gun system for the generation of low energy electrons was designed, developed and characterized. An electron gun having four electrodes namely cathode, focusing electrode, control electrode and anode has been designed for the irradiation experiments. This electron gun is capable to provide electrons of energy over the range of 1 keV to 20 keV, with current maximum upto 100 μA. The electron gun and a faraday cup are mounted in the evacuated cylindrical chamber. The samples are fixed on the faraday cup and irradiated with low energy electrons at a pressure around 10 -6 mbar. In this electron gun system, at any electron energy over the entire range, the electron beam diameter can be varied from 5 to 120 mm on the Faraday cup mounted at a distance of 200 mm from the anode in the chamber. Also, the circular shape of the beam spot was maintained, even though the beam current and beam diameter are varied. The uniformity of the electron beam over the entire beam area was measured with a multi electrode assembly and found to be well within 15%. This system is being used for the synthesis and diffusion of metal and semiconductor nanoparticles in polymeric materials. (author)

Note: Characteristic beam parameter for the line electron gun

Science.gov (United States)

Iqbal, M.; Islam, G. U.; Zhou, Z.; Chi, Y.

2013-11-01

We have optimized the beam parameters of line source electron gun using Stanford Linear Accelerator Centre electron beam trajectory program (EGUN), utilizing electrostatic focusing only. We measured minimum beam diameter as 0.5 mm that corresponds to power density of 68.9 kW/cm2 at 13.5 mm in the post-anode region which is more than two-fold (33 kW/cm2), of the previously reported results. The gun was operated for the validation of the theoretical results and found in good agreement. The gun is now without any magnetic and electrostatic focusing thus much simpler and more powerful.

Note: Characteristic beam parameter for the line electron gun

International Nuclear Information System (INIS)

Iqbal, M.; Islam, G. U.; Zhou, Z.; Chi, Y.

2013-01-01

We have optimized the beam parameters of line source electron gun using Stanford Linear Accelerator Centre electron beam trajectory program (EGUN), utilizing electrostatic focusing only. We measured minimum beam diameter as 0.5 mm that corresponds to power density of 68.9 kW/cm 2 at 13.5 mm in the post-anode region which is more than two-fold (33 kW/cm 2 ), of the previously reported results. The gun was operated for the validation of the theoretical results and found in good agreement. The gun is now without any magnetic and electrostatic focusing thus much simpler and more powerful

Note: Characteristic beam parameter for the line electron gun.

Science.gov (United States)

Iqbal, M; Islam, G U; Zhou, Z; Chi, Y

2013-11-01

We have optimized the beam parameters of line source electron gun using Stanford Linear Accelerator Centre electron beam trajectory program (EGUN), utilizing electrostatic focusing only. We measured minimum beam diameter as 0.5 mm that corresponds to power density of 68.9 kW/cm(2) at 13.5 mm in the post-anode region which is more than two-fold (33 kW/cm(2)), of the previously reported results. The gun was operated for the validation of the theoretical results and found in good agreement. The gun is now without any magnetic and electrostatic focusing thus much simpler and more powerful.

Design and remote fiber communication of NSRL electron gun controller

International Nuclear Information System (INIS)

Wang Weibing; Gao Hui; Hong Jun; Chen Jun; Wang Guicheng; He Duohui; Chen Gang

2005-01-01

A new kind of pulse electron gun controller for 200 MeV LINAC at National Synchrotron Radiation Laboratory was introduced in this paper, including the working principle of the pulse electron gun, the applications of I 2 C serial bus and embedded microcontroller in controlling system. The emphasis is on the hardware design of digital controlled current regulator, digital controlled switch voltage source and high voltage pulse power supply. The software design of fiber communication and PC controlling is also presented. The electron gun controller has successfully been used in NSRL. The result shows that it is quite reliable and the performance is good. This electronic digital system has completely replaced the old mechanical control system. (authors)

Plasma wave observations during electron and ion gun experiments

International Nuclear Information System (INIS)

Olsen, R.C.; Lowery, D.R.; Weddle, L.E.

1988-01-01

Plasma wave instruments with high temporal and frequency resolution in the 0-6 kHz frequency range have been used to monitor electron gun-employing charge control experiments with the USAF/NASA p78-2 satellite, in order to determine whether plasma wave signatures consistent with the previous inference of electron heating were present. Strong plasma waves were noted near the electron gyrofrequency; these waves can heat ambient low energy electrons, as previously inferred. Attention is given to the two distinct classes of behavior revealed by the ion gun experiments. 16 references

Plasma diagnostics by electron guns and electric field probes on ISEE-1

International Nuclear Information System (INIS)

Pedersen, A.

1982-01-01

The use of electron guns to control the potential of a satellite with conductive surfaces is discussed with reference to the results of the ISEE-1 satellite experiment. The two electron guns carried by the satellite can emit electrons with energies up to 48 eV, and the emitted electron current has a maximum value of 0.5-1.0 mA. The satellite potential, with or without gun operation, can be measured with reference to one or two spherical electric field probes positioned on booms at a distance of 36 m from the satellite. The probes are biased with a negative current from a high-impedance source to be slightly positive (0.5-1.0 V) relative to the plasma, and the spacecraft is normally several volts more positive and can be further positively charged by operating the electron gun. Plasma diagnostics can be carried out by appropriate sweeps of gun currents and energy of emitted electrons to obtain information about density and characteristic energy of ambient electrons. 9 references

Large-area cold-cathode grid-controlled electron gun for Antares

International Nuclear Information System (INIS)

Scarlett, W.R.; Andrews, K.; Jansen, J.

1979-01-01

The CO 2 laser amplifiers used in the Antares inertial confinement fusion project require large-area radial beams of high-energy electrons to ionize the laser medium before the main discharge pulse is applied. We have designed a grid-controlled, cold-cathode electron gun with a cylindrical anode having a window area of 9.3 m 2 . A full diameter, 1/4 length prototype of the Antares gun has been built and tested. The design details of the Antares electron gun will be presented as well as test results from the prototype. Techniques used for the prevention and control of emission and breakdown from the grid will also be discussed

Stimulation of plasma waves by electron guns on the ISEE-1 satellite

International Nuclear Information System (INIS)

Lebreton, J.P.; Anderson, R.; Harvey, C.; Torbert, R.

1982-01-01

This chapter describes typical observations of the waves stimulated during the electron injections, when the spacecraft is passing through the magnetosphere, the magnetosheath and the solar wind. Topics considered include orbits of gun electrons, an electric field antenna, gun operation in the magnetosphere, natural waves in the magnetosheath and the solar wind, gun operation magnetosheath, and gun operation in the solar wind. A coupling mechanism between the electron plasma mode and streaming electrons with energies higher than the thermal speed of the cold electron population is proposed to explain the observations above the electron plasma frequency. It is demonstrated that on board the ISEE-1 satellite, the injection of an electron beam current of the order of 10 to 60 251A with energies ranging from 0 to 40 eV produced enhancements in the electric wave spectrum

Modelling and design of high compression electron guns for EBIS/T charge breeders

CERN Document Server

AUTHOR|(CDS)2087190; Zschornack, G.; Lettry, J.; Wenander, F.

In this thesis the optimization of the REXEBIS charge breeder at the ISOLDE facility is presented. REXEBIS in its current state provides a current density of 200A/cm² inside the trapping region at 2 T and will be optimized to the physical limit of its design. To overcome this limit a new electron gun, the HEC² gun, was designed in collaboration with the BNL and is in commission at TestEBIS. This electron gun promises a current density of >10 kA/cm², which decreases the charge breeding time significantly. This thesis presents novel simulation techniques supporting the commissioning phase by explaining the sources of occurring loss current and, in addition, evaluate the currently installed collector for compatibility with the HEC2 gun operating at its design limit. The experience gained from the commission of the HEC² gun and the established numerical techniques lead to the development of a smaller high-compression electron gun for medical purposes, the MEDeGUN. This electron gun should provide a high-quali...

Lifetime measurements using the Jefferson Lad Load-Lock Electron Gun

International Nuclear Information System (INIS)

J. Grames; P. Adderley; M. Baylac; J. Brittian; D. Charles; J. Clark; J. Hansknecht; M. Poelker; M. Stutzman; K. Surles-Law

2000-01-01

Lifetime measurements of bulk GaAs using a 100 kV load-lock electron gun and beam line were made. Initial tests used anodized samples to study lifetime under various conditions (gun vacuum, laser spot location, activated area). Subsequent tests used a mechanical mask to limit the active area and included improved monitoring of the gun chamber and beam line vacuum pressure. Results of these measurements support claims made at past workshops, namely photocathode lifetime improves when gun vacuum is enhanced and when electron emission from the edge of the photocathode is eliminated. The dependence upon laser spot location is less certain. Tests studying lifetime at higher beam intensity (I ∼ 8 mA) have begun

Note: Characteristic beam parameter for the line electron gun

Energy Technology Data Exchange (ETDEWEB)

Iqbal, M. [Centre for High Energy Physics, University of the Punjab, Lahore 45590 (Pakistan); Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Islam, G. U. [Centre for High Energy Physics, University of the Punjab, Lahore 45590 (Pakistan); Zhou, Z.; Chi, Y. [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

2013-11-15

We have optimized the beam parameters of line source electron gun using Stanford Linear Accelerator Centre electron beam trajectory program (EGUN), utilizing electrostatic focusing only. We measured minimum beam diameter as 0.5 mm that corresponds to power density of 68.9 kW/cm{sup 2} at 13.5 mm in the post-anode region which is more than two-fold (33 kW/cm{sup 2}), of the previously reported results. The gun was operated for the validation of the theoretical results and found in good agreement. The gun is now without any magnetic and electrostatic focusing thus much simpler and more powerful.

Thermomechanical Impact of Polyurethane Potting on Gun Launched Electronics

Directory of Open Access Journals (Sweden)

A. S. Haynes

2013-01-01

Full Text Available Electronics packages in precision guided munitions are used in guidance and control units, mission computers, and fuze-safe-and-arm devices. They are subjected to high g-loads during gun launch, pyrotechnic shocks during flight, and high g-loads upon impact with hard targets. To enhance survivability, many electronics packages are potted after assembly. The purpose of the potting is to provide additional structural support and shock damping. Researchers at the US Army recently completed a series of dynamic mechanical tests on a urethane-based potting material to assess its behavior in an electronics assembly during gun launch and under varying thermal launch conditions. This paper will discuss the thermomechanical properties of the potting material as well as simulation efforts to determine the suitability of this potting compound for gun launched electronics. Simulation results will compare stresses and displacements for a simplified electronics package with and without full potting. An evaluation of the advantages and consequences of potting electronics in munitions systems will also be discussed.

Low emittance electron beam formation with a 17 GHz RF gun

Directory of Open Access Journals (Sweden)

W. J. Brown

2001-08-01

Full Text Available We report on electron beam quality measurement results from the Massachusetts Institute of Technology 17 GHz RF gun experiment. The 1.5 cell RF gun uses a solenoid for emittance compensation. It has produced bunch charges up to 0.1 nC with beam energies up to 1 MeV. The normalized rms emittance of the beam after 35 cm of transport from the gun has been measured by a slit technique to be 3π mm mrad for a 50 pC bunch. This agrees well with PARMELA simulations at these beam energies. At the exit of the electron gun, we estimate the emittance to be about 1π mm mrad, which corresponds to a beam brightness of about 80 A/(π mm mrad^{2}. Improved beam quality should be possible with a higher energy output electron beam from the gun.

Emittance growth in laser-driven RF electron guns

International Nuclear Information System (INIS)

Kim, K.J.

1989-01-01

A simple analysis for the evolution of the electron-beam phase space distribution in laser-driven rf guns is presented. In particular, formulas are derived for the transverse and longitudinal emittances at the exit of the gun. The results are compared and found to agree well with those from simulation. (Author). 9 refs.; 4 figs

The system of RF beam control for electron gun

International Nuclear Information System (INIS)

Barnyakov, A.M.; Levichev, A.E.; Chernousov, Yu.D.; Ivannikov, V.I.; Shebolaev, I.V.

2015-01-01

The system of RF control of three-electrode electron gun current is described. It consists of a source of microwave signal, coaxial line, coaxial RF switch and RF antenna lead. The system allows one to get the electron beam in the form of bunches with the frequency of the accelerating section to achieve the capture of particles in the acceleration mode close to 100%. The results of calculation and analysis of the elements of the system are presented. Characteristics of the devices are obtained experimentally. The results of using RF control in three-electrode electron gun at electron linear accelerator are described

Gunning for accuracy: Company targets human error with 'foolproof' perforating gun

Energy Technology Data Exchange (ETDEWEB)

Ross, E.

2002-12-01

An innovative new design for a scalloped expandable perforating gun is described. The gun is manufactured in Edmonton by LRI Perforating Systems, and it aimed at reducing the chances of human error that can result in sub-optimal performance. A perforating gun is used to pierce the well's casing to allow hydrocarbons to flow into the wellbore. It consists of a carrier, a pipe with an eighth-inch thick wall that protects the explosives downhole, and an inner tube containing the explosives. The LRI system has a unique interlocking mechanism for the end plates, which are attached to either end of the thin-walled charge holder tube, in addition to other advantageous features, including a price advantage of 10 to 15 per cent. Marketing strategy is designed to interest wi reline companies that focus on vertical well applications. 1 photo.

Method of electron emission control in RF guns

International Nuclear Information System (INIS)

Khodak, I.V.; Kushnir, V.A.

2001-01-01

The electron emission control method for a RF gun is considered.According to the main idea of the method,the additional resonance system is created in a cathode region where the RF field strength could be varied using the external pulse equipment. The additional resonance system is composed of a coaxial cavity coupled with a RF gun cylindrical cavity via an axial hole. Computed results of radiofrequency and electrodynamic performances of such a two-cavity system and results of the RF gun model pilot study are presented in. Results of particle dynamics simulation are described

Method of electron emission control in RF guns

CERN Document Server

Khodak, I V

2001-01-01

The electron emission control method for a RF gun is considered.According to the main idea of the method,the additional resonance system is created in a cathode region where the RF field strength could be varied using the external pulse equipment. The additional resonance system is composed of a coaxial cavity coupled with a RF gun cylindrical cavity via an axial hole. Computed results of radiofrequency and electrodynamic performances of such a two-cavity system and results of the RF gun model pilot study are presented in. Results of particle dynamics simulation are described.

Single-side electron multipacting at the photocathode in rf guns

Directory of Open Access Journals (Sweden)

Jang-Hui Han

2008-01-01

Full Text Available Multiple electron impacting (multipacting can take place in rf fields when the rf components are composed of materials with a secondary electron yield greater than one. In rf gun cavities, multipacting may change the properties of the vacuum components or even damage them. First systematic measurements of the multipacting occurring in a photocathode rf gun were made at the Fermilab/NICADD Photoinjector Laboratory in 2000. The multipacting properties were found to depend on the cathode material and the solenoid field configuration. In this study, we measure the multipacting properties in more detail and model the secondary electron generation for numerical simulation. Measurements and simulations for the photoinjectors at Fermilab and DESY are compared. The multipacting takes place at the photocathode in rf guns and is categorized as single-side multipacting. In a low rf field, the electrons emitted from the cathode area do not leave the gun cavity within one rf cycle and have an opportunity to travel back and hit the cathode. The solenoid field distribution in the vicinity of the cathode changes the probability of electron bombardment of the cathode and makes a major contribution to the multipacting behavior.

High-voltage pulse generator for electron gun power supply

International Nuclear Information System (INIS)

Korenev, S.A.; Enchevich, I.B.; Mikhov, M.K.

1987-01-01

High-voltage pulse generator with combined capacitive and inductive energy storages for electron gun power supply is described. Hydrogen thyratron set in a short magnetic lense is a current breaker. Times of current interruption in thyratrons are in the range from 100 to 300 ns. With 1 kV charging voltage of capacitive energy storage 25 kV voltage pulse is obtained in the load. The given high-voltage pulse generator was used for supply of an electron gun generating 10-30 keV low-energy electron beam

Upgraded G-optk program for electron gun characterization

International Nuclear Information System (INIS)

Nagasao, K.; Takebe, M.; Ushio, W.; Fujita, S.; Ohye, T.; Shimoyama, H.

2011-01-01

The generalized trajectory theory (the G-optk program) has been extended in order to make the method applicable to electron guns with curved and/or asymmetric cathodes. The object-image analysis mode has also been added. Enhanced capability of the upgraded G-optk program was demonstrated by applying the program to three electron optical systems: (a) the point cathode gun, (b) the hairpin-type cathode gun, and (c) the LEEM objective lens. The Canonical Mapping Transformation (CMT) diagrams were calculated both by direct ray tracing and by the upgraded G-optk program. In each case, it was found that the upgraded program reproduces well the results obtained by ray tracing. The generalized trajectory method has several advantages over direct ray tracing, such as substantially lighter calculation load and easy interpretation of the calculation results in terms of the optical parameters.

Unstable oscillatory Pierce modes of neutralized electron beams

International Nuclear Information System (INIS)

Cary, J.R.; Lemons, D.S.

1982-01-01

Oscillatory modes of the Pierce system have been calculated. These modes are found to have growth rates comparable to the previously investigated purely growing modes. When these modes are included, it is found that the Pierce system is unstable for most values of ω/sub p/ L/V 0 >π

An rf modulated electron gun pulser for linacs

International Nuclear Information System (INIS)

Legg, R.; Hartline, R.

1991-01-01

Present linac injector designs often make use of sub-harmonic prebuncher cavities to properly bunch the electron beam before injection into a buncher and subsequent accelerating cavities. This paper proposes an rf modulated thermionic gun which would allow the sub-harmonic buncher to be eliminated from the injector. The performance parameters for the proposed gun are 120 kV operating voltage, macropulse duration-single pulse mode 2 nsec, multiple pulse mode 100 nsec, rf modularing frequency 500 MHz, charge per micropulse 0.4 nC, macropulse repetition frequency 10 Hz (max). The gun pulser uses a grid modulated planar triode to drive the gun cathode. The grid driver takes advantage of recently developed modular CATV rf drivers, high performance solid state pulser devices, and high-frequency fiber optic transmitters for telecommunications. Design details are presented with associated SPICE runs simulating operation of the gun

Emittance measurement for high-brightness electron guns

International Nuclear Information System (INIS)

Kobayashi, H.; Kurihara, T.; Sato, I.; Asami, A.; Yamazaki, Y.; Otani, S.; Ishizawa, Y.

1992-01-01

An emittance measurement system based on a high-precision pepper-pot technique has been developed for electron guns with low emittance of around πmm-mrad. Electron guns with a 1 mmφ cathode, the material of which is impregnated tungsten or single-crystal lanthanum hexaboride (La 1-x Ce x )B 6 , have been developed. The performance has been evaluated by putting stress on cathode roughness, which gives rise to an angular divergence, according to the precise emittance measurement system. A new type of cathode holder, which is a modified version of the so called Vogel type, was developed and the beam uniformity has been improved. (Author) 5 figs., tab., 9 refs

Heat load of a P-doped GaAs photocathode in SRF electron gun

International Nuclear Information System (INIS)

Wang, E.; Ben-Zvi, I.; Kewisch, J.; Burrill, A.; Rao, T.; Wu, Q.; Jain, A.; Gupta, R.; Holmes, D.

2010-01-01

Many efforts were made over the last decades to develop a better polarized electron source for the high energy physics. Several laboratories operate DC guns with the Gallium-Arsenide photo-cathode, which yield a highly polarized electron beam. However, the beam's emittance might well be improved using a Superconducting RF electron gun, which delivers beams of higher brightness than DC guns does, because the field gradient at the cathode is higher. SRF guns with metal cathodes and CsTe cathodes have been tested successfully. To produce polarized electrons, a Gallium-Arsenide photo-cathode must be used: an experiment to do so in a superconducting RF gun is under way at BNL. Since the cathode will be normal conducting, the problem about the heat load stemming from the cathode arises. We present our measurements of the electrical resistance of GaAs at cryogenic temperatures, a prediction of the heat load and the verification by measuring the quality factor of the gun with and without cathode.

JAERI 200 kV electron gun with an NEA-GaAs photocathode

International Nuclear Information System (INIS)

Nishitani, Tomohiro; Minehara, Eisuke J.; Hajima, Ryoichi; Nagai, Ryoji; Sawamura, Masaru; Nishimori, Nobuyuki; Kikuzawa, Nobuhiro; Yamauchi, Toshihiko

2004-01-01

The photocathode DC-gun with high average current, low beam emittance and long operational lifetime is considered to be indispensable for ERL-FEL. We have started the development program of a 200 keV electron gun with the NEA-GaAs photocathode for the first time in JAERI. In order to long an NEA surface lifetime, the JAERI 200 kV electron gun system consists of a 200 kV DC-gun chamber on extreme high vacuum condition and an NEA activation chamber with load-lock system. We report the goal of photocathode DC-gun R and D and the schedule of a developmental program. (author)

Thermionic gun control system for the CEBAF [Continuous Electron Beam Accelerator Facility] injector

International Nuclear Information System (INIS)

Pico, R.; Diamond, B.; Fugitt, J.; Bork, R.

1989-01-01

The injector for the CEBAF accelerator must produce a high-quality electron beam to meet the overall accelerator specifications. A Hermosa electron gun with a 2 mm-diameter cathode and a control aperture has been chosen as the electron source. This must be controlled over a wide range of operating conditions to meet the beam specifications and to provide flexibility for accelerator commissioning. The gun is controlled using Computer Automated Measurement and Control (CAMAC IEEE-583) technology. The system employs the CAMAC-based control architecture developed at CEBAF. The control system has been tested, and early operating data on the electron gun and the injector beam transport system has been obtained. This system also allows gun parameters to be stored at the operator location, without paralyzing operation. This paper describes the use of this computer system in the control of the CEBAF electron gun. 2 refs., 6 figs., 1 tab

Design and fabrication of a pulsed diode electron gun

International Nuclear Information System (INIS)

Mahadevan, S.; Gandhi, M.L.; Nandedkar, R.V.

2003-01-01

A pulsed diode electron gun has been designed, fabricated and tested and this will be used for the initial hot testing of the Plane Wave Transformer (PWT) linac. The gun is required to deliver 1 A at 70 kV which works out to a current of 500 mA at 40 kV. The gun geometry is optimized using the Electron Trajectory Program EGUN at a mesh size of 0.2 mm. The beam divergence close to cathode caused by an annular gap of 2 mm between cathode and focusing electrode (FE) is compensated by using a suitable focusing electrode. Important features of the pulsed power supply (40 kV, 500 mA, 2 μsec) developed for testing this gun are presented. The current measured at the Faraday cup is in agreement with the designed perveance. Suitable positioning of cathode with respect to the FE helps in further improving the beam quality

Non-channel magnetron gun as the electron source for resonance linear accelerator

International Nuclear Information System (INIS)

Ivanov, G.M.; Makhnenko, L.A.; Cherenshchikov, S.A.

1999-01-01

Studies on the magnetron gun with a cold cathode being part of linear accelerator on the travelling wave are described. Two modes of the gun operation differing by presence of UHF field of the pre-buncher near the gun are observed. In the mode without UHF field the short (about 2 ns) pulses of accelerated electrons with amplitude up to 0.5 A at the gun current up to 20 A were obtained. The presence of UHF field near the gun makes it possible to obtain the beam of higher duration (up to 1.0 μs), but with current up to 20 mA at the accelerator outlet and up to 1 A at the gun outlet. The mechanism of the gun operation is concerned with the secondary-electron current increase and setting self-sustaining secondary emission. Gun characteristics under study are acceptable for the purposes of injection into accelerator [ru

Engineering Design and Fabrication of an Ampere-Class Superconducting Photocathode Electron Gun

International Nuclear Information System (INIS)

Ben-Zvi, I.

2008-01-01

Over the past three years, Advanced Energy Systems and Brookhaven National Laboratory (BNL) have been collaborating on the design of an Ampere- class superconducting photocathode electron gun. BNL performed the physics design of the overall system and RF cavity under prior programs. Advanced Energy Systems (AES) is currently responsible for the engineering design and fabrication of the electron gun under contract to BNL. We will report on the engineering design and fabrication status of the superconducting photocathode electron gun. The overall configuration of the cryomodule will be reviewed. The layout of the hermitic string, space frame, shielding package, and cold mass will be discussed. The engineering design of the gun cavity and removable cathode will be presented in detail and areas of technical risk will be highlighted. Finally, the fabrication sequence and fabrication status of the gun cavity will be discussed

Electron gun for the positron generator

International Nuclear Information System (INIS)

Fukuda, S.; Ogawa, Y.; Saito, Y.

1986-01-01

A triode electron gun has been installed on the Positron Generator at KEK, and brought into test operation. It involves a grid-cathode assembly currently used in a planner triode. The cathode has a diameter of 10 mm and is coated with Ba-Sr-Ca oxide. Because of the short grid-cathode distance (0.18 mm), the relatively low grid pulse voltages makes it possible to draw a high current. The assembly has a small vacuum flange which allows its easy replacement. Emission current from the oxide cathode is sensitive to residual gases, therefore, the vacuum system is carefully made and the pressure is kept in the range of 10 -9 Torr even when the accelerator is on. The grid pulser is a line type pulser using multi-stage avalanche transistors as a switch. The pulse width of 10 nsec has been used for the test to investigate the gun characteristics. The performance of the gun has been tested with this pulser and the emission current of 9.7 A was achieved at an injection voltage of 110 kV. The characteristics of the gun are described together with the beam trace

Longitudinal Jitter Analysis of a Linear Accelerator Electron Gun

Directory of Open Access Journals (Sweden)

MingShan Liu

2016-11-01

Full Text Available We present measurements and analysis of the longitudinal timing jitter of a Beijing Electron Positron Collider (BEPCII linear accelerator electron gun. We simulated the longitudinal jitter effect of the gun using PARMELA to evaluate beam performance, including: beam profile, average energy, energy spread, and XY emittances. The maximum percentage difference of the beam parameters is calculated to be 100%, 13.27%, 42.24% and 65.01%, 86.81%, respectively. Due to this, the bunching efficiency is reduced to 54%. However, the longitudinal phase difference of the reference particle was 9.89°. The simulation results are in agreement with tests and are helpful to optimize the beam parameters by tuning the trigger timing of the gun during the bunching process.

Electron gun design for HIRFL-CSR electron cooler

International Nuclear Information System (INIS)

Rao Yinong; Xia Jiawen; Yuan Youjin; Wei Baowen

1996-01-01

Adiabatic acceleration is employed to design the electron gun of HIRFL-CSR e-cooler by using the modified EGUN code. The electron beam transverse temperature variations with anode region and acceleration tube design parameters as well as the uniform solenoidal magnetic field are presented. Transversal temperature of less than 0.1 eV at a maximum current density of 0.244 A/cm 2 are obtained over the full energy range of 2.75∼165 keV

High-quality electron pulse generation from a laser photocathode RF gun

International Nuclear Information System (INIS)

Yang, Jinfeng; Sakai, Fumio; Aoki, Yasushi

1999-01-01

A laser photocathode RF gun system was developed for ultra short X-ray pulse generation via the inverse Compton scattering. The gun is a BNL-type S-band RF gun and the performance test of the gun was performed at the Linear Accelerator Facility in the Institute of Scientific and Industries Research, Osaka University. The gun system produced 115 pC electron bunches with the energy of 1.6 MeV under the condition of RF peak power of 1.5 MW and laser pulse energy of 65 μJ. The quantum efficiency and dark current were obtained to be 10 -5 and 0.6 nA at the repetition rate of 10 Hz, respectively. The energy and charge of the electron bunch were measured as a function of laser injection phase. Furthermore, the electron bunches were accelerated up to 117 MeV by three s-band TW linacs and the energy monochromaticity (ΔE/E) of the beam was 1.2%. The transverse emittance was also experimentally investigated at the end of the linacs. (author)

An ultrafast nanotip electron gun triggered by grating-coupled surface plasmons

Energy Technology Data Exchange (ETDEWEB)

Schröder, Benjamin; Sivis, Murat; Bormann, Reiner; Schäfer, Sascha; Ropers, Claus, E-mail: cropers@gwdg.de [4th Physical Institute - Solids and Nanostructures, University of Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen (Germany)

2015-12-07

We demonstrate multiphoton photoelectron emission from gold nanotips induced by nanofocusing surface plasmons, resonantly excited on the tip shaft by a grating coupler. The tip is integrated into an electron gun assembly, which facilitates control over the spatial emission sites and allows us to disentangle direct grating emission from plasmon-triggered apex emission. The nanoscale source size of this electron gun concept enables highly coherent electron pulses with applications in ultrafast electron imaging and diffraction.

Power-supply system for high-voltage electron guns with grid control

International Nuclear Information System (INIS)

Grigorev, Y.V.

1985-01-01

A power-supply system for electron guns with grid control is described which consists of a source of accelerating voltage between 20 and 180 kV with a current of 100 mA and a control circuit for an electron gun that contains a pulse generator having an output voltage of up to 5 kV for pulse durations of 2, 10, 50 and 90 microseconds. The output pulses of the generator are synchronized with a certain phase of the cathode heater current of the gun, and they can be repeated at a frequency between 100 and 0.4 Hz. The system is reliable and resistant to the overloads associated with breakdowns in the gun

An electron gun with replaceable cathode-heater assembly for an E-beam irradiator

International Nuclear Information System (INIS)

Wu Xunlei; Yu Xiaojuan; Jiang Zhenbo

2011-01-01

A new type of electron guns has been developed for a 10 MeV 1.5 mA linac for radiation processing. The specifications required are: cathode voltage 60 kV, peak beam current 550-600 mA, spot size 4 mm, and working distance 60 mm. Particularly, this electron gun is advantageous in its replaceable cathode-heater assembly. This helps the customers to reduce their operation cost. The Egun and Mafia codes were used to simulate electromagnetic fields and electron trajectories. The guns were produced in the same technology of our klystron production. Design specifications of the gun were achieved in the beam current test and beam spot test. The first gun of this type has been working on an linac for about 3000 hours. (authors)

OPTIMIZATION OF OPERATION PARAMETERS OF 80-KEV ELECTRON GUN

Directory of Open Access Journals (Sweden)

JEONG DONG KIM

2014-06-01

As a first step, the electron generator of an 80-keV electron gun was manufactured. In order to produce the high beam power from electron linear accelerator, a proper beam current is required form the electron generator. In this study, the beam current was measured by evaluating the performance of the electron generator. The beam current was determined by five parameters: high voltage at the electron gun, cathode voltage, pulse width, pulse amplitude, and bias voltage at the grid. From the experimental results under optimal conditions, the high voltage was determined to be 80 kV, the pulse width was 500 ns, and the cathode voltage was from 4.2 V to 4.6 V. The beam current was measured as 1.9 A at maximum. These results satisfy the beam current required for the operation of an electron linear accelerator.

Developments in electron gun simulation

Science.gov (United States)

Herrmannsfeldt, W. B.

1997-01-01

This paper will discuss the developments in the electron gun simulation programs that are based on EGUN and its derivatives and supporting programs. Much of the code development has been inspired by technology changes in computer hardware; the implications on EGN2 of this evolution will be discussed. Some examples and a review of the capabilities of the EGUN family will be described.

Developments in electron gun simulation

International Nuclear Information System (INIS)

Herrmannsfeldt, W.B.

1994-05-01

This paper will discuss the developments in the electron gun simulation programs that are based on EGUN and its derivatives and supporting programs. Much of the code development has been inspired by technology changes in computer hardware; the implications on EGN2 of this evolution will be discussed. Some examples and a review of the capabilities of the EGUN family will be described

A cusp electron gun for millimeter wave gyrodevices

Science.gov (United States)

Donaldson, C. R.; He, W.; Cross, A. W.; Li, F.; Phelps, A. D. R.; Zhang, L.; Ronald, K.; Robertson, C. W.; Whyte, C. G.; Young, A. R.

2010-04-01

The experimental results of a thermionic cusp electron gun, to drive millimeter and submillimeter wave harmonic gyrodevices, are reported in this paper. Using a "smooth" magnetic field reversal formed by two coils this gun generated an annular-shaped, axis-encircling electron beam with 1.5 A current, and an adjustable velocity ratio α of up to 1.56 at a beam voltage of 40 kV. The beam cross-sectional shape and transported beam current were measured by a witness plate technique and Faraday cup, respectively. These measured results were found to be in excellent agreement with the simulated results using the three-dimensional code MAGIC.

A high current electron gun for the IEAv linac

International Nuclear Information System (INIS)

Muraro, A. Jr.; Stopa, C.R.S.; Romao, B.M.V.; Jorge, A.M.; Takahashi, J.

2001-01-01

This work presents the design, construction and characterization of a new electron gun for the linear electron accelerator (linac) which is under construction at the Instituto de Estudos Avancados (IEAv)

Applications of Electronstatic Lenses to Electron Gun and Energy Analyzers

International Nuclear Information System (INIS)

Sise, O.

2004-01-01

Focal properties and geometries are given for several types of electrostatic lens systems commonly needed in electron impact studies. One type is an electron gun which focuses electrons over a wide range of energy onto a fixed point, such as target, and the other type is an analyzer system which focuses scattered electrons of variable energy onto a fixed position, such as the entrance plane of an analyzer. There are many different types and geometries of these lenses for controlling and focusing of the electron beams. In this presentation we discussed the criteria used for the design of the electrostatic lenses associated with the electron gun and energy analyzers and determined the fundamental relationships between the operation and behaviour of multi-element electrostatic lenses, containing five, six and seven elements. The focusing of the electron beam was achieved by applying suitable voltages to the series of these lens elements, Design of the lens system for electron gun was based on our requirements that the beam at the target had a small spot size and zero beam angle, that is, afocal mode. For energy analyzer systems we considered the entrance of the hemispherical analyzer which determines the energy of the electron beam and discussed the focusing condition of this lens systems

Design of 120 MW beam power electron gun for high power klystron

International Nuclear Information System (INIS)

Zhou Zusheng; Dong Dong

2005-01-01

An electron gun was designed and the beam optics for a China-made 50 MW klystron was simulated. The electron gun ceramic cylinder was designed and optimized. The China-made cathode was replaced with an imported one to lessen evaporation and arcing. The high voltage (320 kV) of the cathode was increased to meet the klystron output power demand and a low electric field strength (22.1 kV/mm) electron gun was designed to avoid the high power operation which damaged the ceramic cylinder. The klystron output power was increased and life span extended. (authors)

Fundamentals for a terahertz-driven electron gun

DEFF Research Database (Denmark)

Lange, Simon Lehnskov; Olsen, Filip D.; Iwaszczuk, Krzysztof

2017-01-01

dipoles placed with a small gap in between. We conclude that it is possible to make ultra-bright electron bunches shorter than 1 ps and accelerate them to the low keV range over 15 mu m using only a single THz transient. Our results are fundamental to understand and build a THz-driven electron gun....

Thermal and mechanical modelling of a mig-type electron gun

International Nuclear Information System (INIS)

Patire Junior, H.; Castro, J.J.B. de

1995-01-01

A thermal and mechanical modelling of a magnetron injection electron gun has been made to minimize the temperature distribution in the gun elements while keeping the required operating temperature at 1000 0 C of the emitter. Appropriate materials were selected to reduce thermal losses and to improve the gun design from a constructional point of view aiming at extending the capabilities of the gun. A software has been used to simulate a thermal model considering the three processes of thermal transfer and the influence of the physical properties of the materials used. (author). 8 refs., 2 figs, 2 tabs

Heat load of a GaAs photocathode in an SRF electron gun

International Nuclear Information System (INIS)

Wang Erdong; Zhao Kui; Jorg Kewisch; Ilan Ben-Zvi; Andrew Burrill; Trivini Rao; Wu Qiong; Animesh Jain; Ramesh Gupta; Doug Holmes

2011-01-01

A great deal of effort has been made over the last decades to develop a better polarized electron source for high energy physics. Several laboratories operate DC guns with a gallium arsenide photocathode, which yield a highly polarized electron beam. However, the beam's emittance might well be improved by using a superconducting radio frequency (SRF) electron gun, which delivers beams of a higher brightness than that from DC guns because the field gradient at the cathode is higher. SRF guns with metal and CsTe cathodes have been tested successfully. To produce polarized electrons, a Gallium-Arsenide photo-cathode must be used: an experiment to do so in a superconducting RF gun is under way at BNL. Since a bulk gallium arsenide (GaAs) photocathode is normal conducting, a problem arises from the heat load stemming from the cathode. We present our measurements of the electrical resistance of GaAs at cryogenic temperatures, a prediction of the heat load and verification by measuring the quality factor of the gun with and without the cathode at 2 K. We simulate heat generation and flow from the GaAs cathode using the ANSYS program. By following the findings with the heat load model, we designed and fabricated a new cathode holder (plug) to decrease the heat load from GaAs. (authors)

Control-grid electron gun as a source of modulated electron beam for a collective accelerator

International Nuclear Information System (INIS)

Bakumenko, A.A.; Belikov, V.V.; Zvyagintsev, A.V.; Lyul'chenko, V.I.; Lymar', A.G.; Martynenko, P.A.; Suryadnyj, A.V.

1989-01-01

Structure is described and experimental results of investigations into an electron gun with transverse beam compression and control grid are presented. The pulse trailing edge is formed by a sectioned discharger. A modulated electron beam with the following parameters: 110 keV beam energy, 70 A current amplitude, 3-8 MHz modulation frequency, 100% modulation depth, ≅8-6 mm minimal beam diameter, ≅ 10μs pulse duration, 3% pulse top non-uniformity, more than 200 compression degree is obtained when introducing the positive feedback in auto-generator regime to the gun supply circuit. Further it is supposed to use the developed electron gun for heavy ion acceleration by a field of space charge of a modulated electron beam in a corrugated liner. It should be underlined that power supply of such an accelerator does not require powerful outside HF generator. 5 refs.; 1 fig

Results from operation of metal melting electron gun

International Nuclear Information System (INIS)

Balloni, A.J.; Paes, A.C.J.; Miliano, A.C.

1988-09-01

The first results obtained during the operation of metal melting electron gun, of power 30Kw and current 1,2A, developed at IEAv, are presented. Details on operation of beam transport system (composed by magnetic lens and prism), from generation to fusion chamber and cathode construction. Into the fusion chamber the presssure can reach 10 -4 Pa, seeing that the gun test consisted in fusion for purification of approximatelly 1Kg titanium bar. The input average power was 12Kw, and the fusion remainded during 16 minutes. The calculated thermal efficiency was of the order of 10% consistent with the results found out in literature, for this type of gun. (M.C.K.) [pt

Orofacial piercings: perceptions of dental practitioners and piercing parlours.

Science.gov (United States)

Chadwick, Barbara L; Groves, Gemma; Dransfield, Kathryn

2005-07-01

To identify the advice given by piercing parlours prior to orofacial piercing and to determine how many dental practitioners see complications from orofacial piercings. Administered questionnaire to 19 piercing parlours and postal questionnaire to 400 dental practitioners in south-east Wales. Ninety-nine per cent of 227 dental practitioners in south-east Wales had treated patients with orofacial piercings, over three-quarters had seen a patient for a complication caused by the piercing, and over half (N=120) had treated a patient for a complication of piercing. Tongue (N=225) and lip (N=209) piercings were most frequently seen and the most commonly occurring complication was fractured or cracked teeth (N=176). Almost all practitioners wanted more information on orofacial piercing and its sequelae. All 19 piercing parlours in south-east Wales warned clients about pain following piercing and 18 mentioned swelling; only four discussed possible damage to teeth and none discussed the risk of airway obstruction. Despite the concerns of dental and medical professionals orofacial piercing remains popular and the complications it causes are frequently seen by dental practitioners. There is a need for literature to assist both dental practitioners and piercers in advising and safeguarding patients.

Numerical design of electron guns and space charge limited transport systems

International Nuclear Information System (INIS)

Herrmannsfeldt, W.B.

1980-10-01

This paper describes the capabilities and limitations of computer programs used to design electron guns and similarly space-charge limited transport systems. Examples of computer generated plots from several different types of gun problems are included

Beam Dynamics Simulation of Photocathode RF Electron Gun at the PBP-CMU Linac Laboratory

Science.gov (United States)

Buakor, K.; Rimjaem, S.

2017-09-01

Photocathode radio-frequency (RF) electron guns are widely used at many particle accelerator laboratories due to high quality of produced electron beams. By using a short-pulse laser to induce the photoemission process, the electrons are emitted with low energy spread. Moreover, the photocathode RF guns are not suffered from the electron back bombardment effect, which can cause the limited electron current and accelerated energy. In this research, we aim to develop the photocathode RF gun for the linac-based THz radiation source. Its design is based on the existing gun at the PBP-CMU Linac Laboratory. The gun consists of a one and a half cell S-band standing-wave RF cavities with a maximum electric field of about 60 MV/m at the centre of the full cell. We study the beam dynamics of electrons traveling through the electromagnetic field inside the RF gun by using the particle tracking program ASTRA. The laser properties i.e. transverse size and injecting phase are optimized to obtain low transverse emittance. In addition, the solenoid magnet is applied for beam focusing and emittance compensation. The proper solenoid magnetic field is then investigated to find the optimum value for proper emittance conservation condition.

Design and experimental results of a new electron gun using a magnetic multipole plasma generator

International Nuclear Information System (INIS)

Tanaka, S.; Yokoyama, K.; Akiba, M.; Araki, M.; Dairaku, M.; Inoue, T.; Mizuno, M.; Okumura, Y.; Ohara, Y.; Seki, M.; Watanabe, K.

1991-01-01

A new electron gun utilizing a magnetic multipole plasma generator was designed and fabricated as the heat source of the high heat flux test facility, called JEBIS (JAERI electron beam irradiation stand). By changing the acceleration grids, this electron gun is able to produce a pencil to a sheetlike electron beams up to 4 A at 100 keV for 1 ms to continuous mode. In this electron gun, magnetic lens system is not adopted to focus the electron beam, but the space charge neutralization effect by the beam plasma produced downstream of the electron gun is utilized to prevent the blow-up of the electron beam. In addition, high permeability metal is embedded in the first and the second grids to magnetically shield the earth field and the stray field from the beam bending magnet. It was experimentally demonstrated that wide range of heat flux from 0.2 MW/m 2 to over 2000 MW/m 2 can be realized at the test sample position about 1.7 m downstream of the electron gun

Modeling electron beam parameters and plasma interface position in an anode plasma electron gun with hydrogen atmosphere

Science.gov (United States)

Krauze, A.; Virbulis, J.; Kravtsov, A.

2018-05-01

A beam glow discharge based electron gun can be applied as heater for silicon crystal growth systems in which silicon rods are pulled from melt. Impacts of high-energy charged particles cause wear and tear of the gun and generate an additional source of silicon contamination. A steady-state model for electron beam formation has been developed to model the electron gun and optimize its design. Description of the model and first simulation results are presented. It has been shown that the model can simulate dimensions of particle impact areas on the cathode and anode, but further improvements of the model are needed to correctly simulate electron trajectory distribution in the beam and the beam current dependence on the applied gas pressure.

High voltage processing of the SLC polarized electron gun

International Nuclear Information System (INIS)

Saez, P.; Clendenin, J.; Garden, C.; Hoyt, E.; Klaisner, L.; Prescott, C.; Schultz, D.; Tang, H.

1993-04-01

The SLC polarized electron gun operates at 120 kV with very low dark current to maintain the ultra high vacuum (UHV). This strict requirement protects the extremely sensitive photocathode from contaminants caused by high voltage (HV) activity. Thorough HV processing is thus required x-ray sensitive photographic film, a nanoammeter in series with gun power supply, a radiation meter, a sensitive residual gas analyzer and surface x-ray spectrometry were used to study areas in the gun where HV activity occurred. By reducing the electric field gradients, carefully preparing the HV surfaces and adhering to very strict clean assembly procedures, we found it possible to process the gun so as to reduce both the dark current at operating voltage and the probability of HV discharge. These HV preparation and processing techniques are described

Three-electrode pulse electron gun with currents up to 250 A

International Nuclear Information System (INIS)

Grigor'ev, Yu.V.; Shanturin, L.P.

1977-01-01

The design and operating conditions of a pulsed electron gun are described. The electron gun has three electrodes: a cathode, an anode and a control electrode in the form of a grid. The cathode is made from lanthanum hexaboride, which ensures its operation in a low vacuum at a temperature of 1,700 deg C. The control electrode and anode grid are fabricated from sheet tantalum. The anode-grid characteristics of the gun are given. It is shown that at an accelerating voltage of 100 kV, a temperature of 1,700 deg C and a zero control electrode potential the beam current is 250 A

Progress of electron gun systems for the e-/e+ linac at KEK

International Nuclear Information System (INIS)

Ohsawa, S.; Ogawa, Y.; Otake, Y.; Yokota, M.; Fukuda, S.; Saito, Y.; Enomoto, A.; Azuma, O.; Iwata, H.; Asami, A.

1989-01-01

Several improvements have been made in the electron gun systems of the 2.5 GeV PF linac and the Positron Generator. In the electron gun system of the PF linac, the vacuum system and the focusing system have been modified, and the anode current was increased. In the case of a short pulse beam with a width of 2 ns, the anode current has been more than 200 mA for about a year with a constant pulse voltage output of a grid pulser. Injection time of the electron beam into the Accumulation Ring of TRISTAN has been normally less than 10 s. Meanwhile in the electron gun system of the Positron Generator, improvements have been made mainly in the following two points; (1) a raise of injection voltage of the gun from 115 kV to 150 kV, which was made possible by using a newly designed insulator, and (2) an increase of pulse voltage output of a grid pulser by use of new transistors with a high slew rate. As a result of these improvements, a maximum anode peak current of 12 A with a pulse width of 4 ns can be obtained, which satisfies the design parameters of the gun system. 7 refs., 8 figs

Design and development of line type modulators for high impedance electron gun

Energy Technology Data Exchange (ETDEWEB)

Dixit, Kavita P.; Tillu, Abhijit; Chavan, Ramchandra; Yadav, Vivek; Sarukte, Hemant, E-mail: kavidi@barc.gov.in [Accelerator and Pulse Power Division, Bhabha Atomic Research Centre, Mumbai (India)

2014-07-01

Conventional line type modulators are routinely used for powering pulsed power microwave devices such as magnetrons and klystrons used for radar, medical and scientific applications. The load impedance (operating point) is fairly well defined in these cases, and makes the design of the discharging circuit of the modulator straight forward. This paper describes the Line type modulators that have been developed and being routinely used for powering the Triode Electron Gun of industrial electron linacs. The beam parameters of such guns are user defined and the pulse current varies from few mA to 800mA (typ). The beam energies requirement varies from 40 keV to 80 keV. Hence the impedance offered by the electron gun to the power source (modulator) is not well defined. The load capacitance which is inclusive of the various stray capacitances along with the intrinsic gun capacitance is ∼ 200-400 pF. This capacitance, which depends on the configuration, shunts the load and makes the effective load highly capacitive with the resistive part varying over a wide range. The paper describes the design and development of conventional line type modulators for powering Electron gun load of the type described above. (author)

Design of a LaB 6 gun using EGN2 and INTMAG

Science.gov (United States)

Becker, R.; Herrmannsfeldt, W. B.

1990-12-01

In order to launch a high-density electron beam to be focused in the 5 T superconducting solenoid of the Frankfurt EBIS [R. Becker et al., Nucl. Instr. and Meth. B24 (1987) 838], an electron gun has been designed, with a 0.5 mm diameter LaB 6 cathode (FEI Comp., Beaverton, USA) in a 70 mm diameter electrode geometry. The emitting surface is placed in the axial fringing field of the solenoid, modified by an axial shielding disk and a bucking coil, to provide either immersed flow or Brillouin flow conditions for the focused beam. Since the cathode diameter is small as compared to the electrodes, a new feature of EGN2 [W.B. Herrmannsfeldt, SLAC-331 (1988)] had to be used in order to have a sufficient number of meshes along the emitting surface. By starting a field line in the large geometry, a curved Neumann boundary is found for a subdivided part of the gun, which represents the influence of the larger part. EGN2 writes the coordinates of this field line on a file, which can be used by POLYGON [R. Becker, Nucl. Instr. and Meth. B42 (1989) 162] (a boundary setup program for EGN2) to define a curved Neumann boundary. By this procedure, it becomes possible to get a reliable simulation of the emission properties of a small cathode in large gun electrodes. The magnetostatic field calculations have been performed with INTMAG [R. Becker, Nucl. Instr. and Meth. B42 (1989) 303], which is a new program of the boundary element method type. Due to the integration calculus, the results do not need smoothing or "Maxwellisation" for the use in EGN2, where the off-axis fields are evaluated by radial expansion. INTMAG provides an output file, which is suitably formatted to be read in by EGN2. The gun design is based on space-charge-limited emission, but no Pierce-type electrode has been provided in the vicinity of the cathode; instead a Wehnelt electrode on negative bias with respect to the cathode is used to create the correct Pierce-type equipotential in free space, ending on the

Thermal characterization of indirectly heated axi-symmetric solid cathode electron beam gun for melting application

International Nuclear Information System (INIS)

Prakash, B.; Gupta, S.; Malik, P.; Mishra, K.K.; Jha, M.N.; Kandaswamy, E.; Martin, M.

2015-01-01

Electron beam melting gun with indirectly heated axi-symmetric solid cathode was designed, fabricated and characterized experimentally. The thermal simulation and optical analysis of the electron gun was carried out to estimate the power required to achieve the emission temperature of the solid cathode, to obtain the temperature distribution in the assembly and the beam transportation. On the basis of the thermal simulation and electron optics, the electron gun design was finalised. The electron gun assembly was fabricated and installed in the vacuum chamber for carrying out the experiment to find the actual temperature distribution. Thermocouple and two colour pyrometer were used to measure the temperature at various locations in the electron gun. The attenuation effect of the viewing port glass of the vacuum chamber was compensated in the final reading of the temperature measured by the pyrometer. The temperature of solid cathode obtained by the experiment was found to be 2800K which is the emission temperature of solid cathode. (author)

Investigation and optimisation of a plasma cathode electron beam gun for material processing applications

OpenAIRE

Del Pozo Rodriguez, Sofia

2016-01-01

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University London. This thesis describes design, development and testing work on a plasma cathode electron beam gun as well as plasma diagnosis experiments and Electron Beam (EB) current measurements carried out with the aim of maximising the power of the EB extracted and optimising the electron beam gun system for material processing applications. The elements which influence EB gun design are described...

Annular-cathode electron gun for in-line injection in a racetrack microtron

International Nuclear Information System (INIS)

Manca, J.J.; Edmonds, D.S. Jr.; Froelich, H.R.

1976-01-01

A compact annular-cathode electron gun which allows direct, efficient injection into the accelerating structure of a racetrack microtron was designed, built, and tested. The gun operates under pulsed conditions with applied high voltages of 40 kV or more and delivers an output current in excess of 1 A. Design and construction details are presented for both a basic gun and a gun with built-in output current monitor. Gun performance in a test chamber and in the multicavity racetrack microtron at the University of Western Ontario is described

A pulsed electron gun for the Plane Wave Transformer Linac

Science.gov (United States)

Mahadevan, S.; Gandhi, M. L.; Nandedkar, R. V.

2003-01-01

A pulsed diode electron gun delivering 500 mA current at 40 kV is described. The gun geometry is optimized using the Electron Trajectory Program EGUN at higher scaling factors by choosing the closest converging starting surface. The effect of an annular gap between cathode and focusing electrode on beam behaviour is compensated by using a suitable focusing electrode. The estimated perveance is 0.065 μperv and the normalized emittance is within 5 π mm mrad. The variation in current density at the cathode has been limited to within 10% across the face of the cathode. Salient features of the pulsed power supply and an insight of its interconnection with the gun are presented. The current measured at the Faraday cup is in agreement with the designed perveance.

A pulsed electron gun for the Plane Wave Transformer Linac

Energy Technology Data Exchange (ETDEWEB)

Mahadevan, S. E-mail: maharaja@cat.ernet.in; Gandhi, M.L. E-mail: mlg@cat.ernet.in; Nandedkar, R.V. E-mail: nrv@cat.ernet.in

2003-01-01

A pulsed diode electron gun delivering 500 mA current at 40 kV is described. The gun geometry is optimized using the Electron Trajectory Program EGUN at higher scaling factors by choosing the closest converging starting surface. The effect of an annular gap between cathode and focusing electrode on beam behaviour is compensated by using a suitable focusing electrode. The estimated perveance is 0.065 {mu}perv and the normalized emittance is within 5{pi} mm mrad. The variation in current density at the cathode has been limited to within 10% across the face of the cathode. Salient features of the pulsed power supply and an insight of its interconnection with the gun are presented. The current measured at the Faraday cup is in agreement with the designed perveance.

A pulsed electron gun for the Plane Wave Transformer Linac

CERN Document Server

Mahadevan, S; Nandedkar, R V

2003-01-01

A pulsed diode electron gun delivering 500 mA current at 40 kV is described. The gun geometry is optimized using the Electron Trajectory Program EGUN at higher scaling factors by choosing the closest converging starting surface. The effect of an annular gap between cathode and focusing electrode on beam behaviour is compensated by using a suitable focusing electrode. The estimated perveance is 0.065 mu perv and the normalized emittance is within 5 pi mm mrad. The variation in current density at the cathode has been limited to within 10% across the face of the cathode. Salient features of the pulsed power supply and an insight of its interconnection with the gun are presented. The current measured at the Faraday cup is in agreement with the designed perveance.

A pulsed electron gun for the Plane Wave Transformer Linac

International Nuclear Information System (INIS)

Mahadevan, S.; Gandhi, M.L.; Nandedkar, R.V.

2003-01-01

A pulsed diode electron gun delivering 500 mA current at 40 kV is described. The gun geometry is optimized using the Electron Trajectory Program EGUN at higher scaling factors by choosing the closest converging starting surface. The effect of an annular gap between cathode and focusing electrode on beam behaviour is compensated by using a suitable focusing electrode. The estimated perveance is 0.065 μperv and the normalized emittance is within 5π mm mrad. The variation in current density at the cathode has been limited to within 10% across the face of the cathode. Salient features of the pulsed power supply and an insight of its interconnection with the gun are presented. The current measured at the Faraday cup is in agreement with the designed perveance

Summary, Working Group 1: Electron guns and injector designs

International Nuclear Information System (INIS)

Ben-Zvi, I.; Bazarov, I.V.

2006-01-01

We summarize the proceedings of Working Group 1 of the 2005 Energy Recovery Linac (ERL) Workshop. The subject of this working group, the electron gun and injector design, is arguably the most critical part of the ERL as it determines the ultimate performance of this type of accelerators. Working Group 1 dealt with a variety of subjects: The technology of DC, normal-conducting RF and superconducting RF guns; beam dynamics in the gun and injector; the cathode and laser package; modeling and computational issues; magnetized beams and polarization. A short overview of these issues covered in the Working Group is presented in this paper

Low Emittance Guns for the ILC Polarized Electron Beam

International Nuclear Information System (INIS)

Clendenin, J. E.; Brachmann, A.; Ioakeimidi, K.; Kirby, R. E.; Maruyama, T.; Miller, R. H.; Wang, J. W.; Zhou, F.

2007-01-01

Polarized electron beams generated by DC guns are routinely available at several accelerators including JLAB, Mainz and SLAC. These guns operate with a cathode bias on the order of -100 kV. To minimize space charge effects, relatively long bunches are generated at the gun and then compressed longitudinally external to the gun just before and during initial acceleration. For linear colliders, this compression is accomplished using a combination of rf bunchers. For the basic design of the International Linear Collider (ILC), a 120 kV DC photocathode gun is used to produce a series of nanosecond bunches that are each compressed by two sub-harmonic bunchers (SHBs) followed by an L-band buncher and capture section. The longitudinal bunching process results in a significantly higher emittance than produced by the gun alone. While high-energy experiments using polarized beams are not generally sensitive to the source emittance, there are several benefits to a lower source emittance including a simpler more efficient injector system and a lower radiation load during transport especially at bends as at the damping ring. For the ILC, the SHBs could be eliminated if the voltage of the gun is raised sufficiently. Simulations using the General Particle Tracer (GPT) package indicate that a cathode bias voltage of ≥200 kV should allow both SHBs to be operated at 433 or even 650 MHz, while ≥500 kV would be required to eliminate the SHBs altogether. Simulations can be used to determine the minimum emittance possible if the injector is designed for a given increased voltage. A possible alternative to the DC gun is an rf gun. Emittance compensation, routinely used with rf guns, is discussed for higher-voltage DC guns

Low Emittance Guns for the ILC Polarized Electron Beam

International Nuclear Information System (INIS)

Clendenin, J.E.; Brachmann, A.; Ioakeimidi, K.; Kirby, R.E.; Maruyama, T.; Miller, R.H.; Wang, J.W.; Zhou, F.; SLAC

2006-01-01

Polarized electron beams generated by DC guns are routinely available at several accelerators including JLAB, Mainz and SLAC. These guns operate with a cathode bias on the order of -100 kV. To minimize space charge effects, relatively long bunches are generated at the gun and then compressed longitudinally external to the gun just before and during initial acceleration. For linear colliders, this compression is accomplished using a combination of rf bunchers. For the basic design of the International Linear Collider (ILC), a 120 kV DC photocathode gun is used to produce a series of nanosecond bunches that are each compressed by two sub-harmonic bunchers (SHBs) followed by an L-band buncher and capture section. The longitudinal bunching process results in a significantly higher emittance than produced by the gun alone. While high-energy experiments using polarized beams are not generally sensitive to the source emittance, there are several benefits to a lower source emittance including a simpler more efficient injector system and a lower radiation load during transport especially at bends as at the damping ring. For the ILC, the SHBs could be eliminated if the voltage of the gun is raised sufficiently. Simulations using the General Particle Tracer (GPT) package indicate that a cathode bias voltage of (ge)200 kV should allow both SHBs to be operated at 433 or even 650 MHz, while (ge)500 kV would be required to eliminate the SHBs altogether. Simulations can be used to determine the minimum emittance possible if the injector is designed for a given increased voltage. A possible alternative to the DC gun is an rf gun. Emittance compensation, routinely used with rf guns, is discussed for higher-voltage DC guns

A NEW THERMIONIC RF ELECTRON GUN FOR SYNCHROTRON LIGHT SOURCES

Energy Technology Data Exchange (ETDEWEB)

Kutsaev, Sergey; Agustsson, R.; Hartzell, J; Murokh, A.; Nassiri, A.; Savin, E.; Smirnov, A.V.; Smirnov, A. Yu; Sun, Y.; Verma, A; Waldschmidt, Geoff; Zholents, A.

2017-06-02

A thermionic RF gun is a compact and efficient source of electrons used in many practical applications. RadiaBeam Systems and the Advanced Photon Source at Argonne National Laboratory collaborate in developing of a reliable and robust thermionic RF gun for synchrotron light sources which would offer substantial improvements over existing thermionic RF guns and allow stable operation with up to 1A of beam peak current at a 100 Hz pulse repetition rate and a 1.5 μs RF pulse length. In this paper, we discuss the electromagnetic and engineering design of the cavity and report the progress towards high power tests of the cathode assembly of the new gun.

Electron-optical system of 200 kV gun for the VEPP-5 preinjector

International Nuclear Information System (INIS)

Akimov, V.E.; Kazarezov, I.V.; Tiunov, M.A.

2004-01-01

The electron gun with a new electron-optical system to match project parameters of the VEPP-5 preinjector is described. The gun produces the current with 10 A amplitude, pulse duration 2...3 ns at half-height and electron energy 200 keV. The gun has a dispenser cathode 20 mm in diameter and 100 mm spherical radius. The current control is performed by means of molybdenum equipotential grid with the cell size 0.4 centre dot 0.4 mm and optical transparency of about 0.68. The experimental results obtained are in good agreement with project parameters

Pulsed WIP electron gun. Fabrication phase 1 x 40 cm and 1 x 70 cm cooled WIP electron gun. Final report, March 1979-December 1980

International Nuclear Information System (INIS)

Wakalopulos, G.

1980-01-01

An electron gun capable of long-run operation at 10 KHz and 1 A/cm 2 has been fabricated and tested. Pulse widths of 200 to 600 nsec and a total life of greater than 10 7 shots have been demonstrated. During the acceptance tests, the electron gun was operated at a total average power of 20 KW for 30 minutes. This basically satisfied the contract requirements. To establish some upper limit of the gun's capability, the device was operated at a repetition rate of 3.5 KHz at a total average power of 54.5 KW for greater than 10 minutes. During these tests, no high voltage breakdown occurred after the device was processed. The beam uniformity at high repetition rates is +-10% and the efficiency is 50%

Secondary emission ion analyzer provided with an electron gun for insulating material analysis

International Nuclear Information System (INIS)

Blanchard, Bruno; Carrier, Patrick; Marguerite, J.-L.; Rocco, J.-C.

1976-01-01

This invention relates to a secondary emission ion analyser, fitted with an electron gun. It is used in the mass spectrometry analysis of electrically insulating bodies. It has already been suggested to bombard the target with an electron beam in conjunction with the beam of primary particles, in order to reduce the space charge near the target. The object of this invention is the application of this known process to appliances of the ion analyser type with a high electric field near the target. Its main characteristic is the use of an electron gun emitting an electron beam through the extraction lens placed opposite the target. The extraction electric field influences the path of the electrons but the electric and mechanical specifications of the electron gun in the invention are such that the target is correctly sprayed by the electron beam [fr

Pierce-type dispersion relation for an intense relativistic electron beam interacting with a slow-wave structure

International Nuclear Information System (INIS)

Chen, C.

1994-01-01

A Pierce-type dispersion relation is derived for the interaction of an intense relativistic electron beam with a cylindrical slow-wave structure of arbitrary corrugation depth. It is shown that near a resonance, the Pierce parameter can be expressed in terms of the vacuum dispersion function and the beam current. The dispersion relation is valid in both the low-current (Compton) regime and the high-current (Raman) regime. The dispersion characteristics of the interaction, such as the linear instability growth rate and bandwidth, are analyzed for both regimes

Convective and conduction heat transfer study on a mig-type electron gun

International Nuclear Information System (INIS)

Patire Junior, H.; Barroso, J.J.

1996-01-01

A convective and conducting heat transfer study of a magnetron injection electron gun has been made to minimize the temperature distribution in the gun elements while keeping the required operating temperature at 1000 0 C of the emitter. Appropriate materials were selected to reduce thermal losses and to improve the gun design from a constructional point of view aiming at extending the capabilities of the electron gun. A thermal probe to determine the air velocity and the convective heat transfer coefficient has been constructed to determine the external boundary condition of the ceramic shell and external flanges. A study the contact resistance for all the gun elements has been made to minimize the conduction thermal losses. A software has been used to simulate a thermal model considering the three processes of thermal transfer, namely, conduction, convection and radiation and the influence of the physical properties of the materials used. (author). 7 refs., 5 figs., 1 tab

Virtual cathode driven by short pulse electron gun

International Nuclear Information System (INIS)

Spassovsky, I.P.; Cho, Sung Oh; Lee, Jongmin; Lee, Byung-Cheol; Jeong, Young Uk; Messina, G.; Yovchev, I.G.; Nikolov, N.A.

1996-01-01

An electron gun has been developed by ENEA (Italy) to power a free-electron laser operating in the far infrared region. The device can also be used to drive various microwave sources. Numerical simulations were performed for the planned foil-diode vircator experiment to be carried out by ENEA. (author). 5 figs., 4 refs

Virtual cathode driven by short pulse electron gun

Energy Technology Data Exchange (ETDEWEB)

Spassovsky, I P; Cho, Sung Oh; Lee, Jongmin; Lee, Byung-Cheol; Jeong, Young Uk [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of). Laboratory for Quantum Optics; Messina, G [ENEA, Roma-Frascati (Italy). INN-FIS-LAC; Yovchev, I G; Nikolov, N A [Sofia Univ. (Bulgaria). Faculty of Physics

1997-12-31

An electron gun has been developed by ENEA (Italy) to power a free-electron laser operating in the far infrared region. The device can also be used to drive various microwave sources. Numerical simulations were performed for the planned foil-diode vircator experiment to be carried out by ENEA. (author). 5 figs., 4 refs.

Electron emission and plasma generation in a modulator electron gun using ferroelectric cathode

International Nuclear Information System (INIS)

Chen Shutao; Zheng Shuxin; Zhu Ziqiu; Dong Xianlin; Tang Chuanxiang

2006-01-01

Strong electron emission and dense plasma generation have been observed in a modulator electron gun with a Ba 0.67 Sr 0.33 TiO 3 ferroelectric cathode. Parameter of the modulator electron gun and lifetime of the ferroelectric cathode were investigated. It was shown that electron emission from Ba 0.67 Sr 0.33 TiO 3 cathode with a positive triggering pulse is a sort of plasma emission. Electrons were emitted by the co-effect of surface plasma and non-compensated negative polarization charges at the surface of the ferroelectric. The element analyses of the graphite collector after emission process was performed to show the ingredient of the plasma consist of Ba, Ti and Cu heavy cations of the ceramic compound and electrode. It was demonstrated the validity of the Child-Langmuir law by introducing the decrease of vacuum gap and increase of emission area caused by the expansion of the surface plasma

Polarized Light Sources for photocathode electron guns at SLAC

International Nuclear Information System (INIS)

Woods, M.; Frisch, J.; Witte, K.; Zolotorev, M.

1992-12-01

We describe current and future Polarized Light Sources at SLAC for use with photocathode electron guns to produce polarized electron beams. The SLAC experiments SLD and E142 are considered, and are used to define the required parameters for the Polarized Light Sources

Generation of femtosecond electron single pulse using laser photocathode RF gun

Energy Technology Data Exchange (ETDEWEB)

Uesaka, M.; Kinoshita, K.; Watanabe, T. [Nuclear Engineering Research Laboratory, University of Tokyo, Tokai, Ibaraki (JP)] [and others

1998-11-01

A new laser photocathode RF electron gun was installed in the second linac of the S-band twin linac system of Nuclear Engineering Research Laboratory(NERL) of University of Tokyo in August in 1997. Since then, the behavior of the new gun has been tested and the characteristic parameters have been evaluated. At the exit of the gun, the energy is 4.7 MeV, the charge per bunch 1 nC, the pulse width is 10 ps(FWHM), respectively, for 6 MW RF power supply from a klystron. The electron bunch is accelerated up to 17 MeV. The horizontal normalized emittance is 1 {pi} mm.mrad. Then, the bunch is compressed to be 440 fs(FWHM) with 0.35 nC by the chicane-type magnetic pulse compressor. The gun is planned to be used for femtosecond X-ray generation via the head-on Thomson scattering and laser wakefield acceleration in 1998. (author)

Quantum efficiency temporal response and lifetime of a GaAs cathode in SRF electron gun

International Nuclear Information System (INIS)

Wang, E.; Ben-Zvi, I.; Kewisch, J.; Burrill, A.; Rao, T.; Wu, Q.; Holmes, D.

2010-01-01

RF electron guns with a strained super lattice GaAs cathode can generate polarized electron beam of higher brightness and lower emittance than do DC guns, due to their higher field gradient at the cathode's surface. In a normal conducting RF gun, the extremely high vaccum required by these cathodes can not be met. We report on an experiment with a superconducting SRF gun, which can maintain a vacuum of nearly 10-12 torr because of cryo-pumping at the temperature of 4.2K. With conventional activation, we obtained a QE of 3% at 532 nm, with lifetime of nearly 3 days in the preparation chamber. We plan to use this cathode in a 1.3 GHz 1/2 cell SRF gun to study its performance. In addition, we studied the multipacting at the location of cathode. A new model based on the Forkker-Planck equation which can estimate the bunch length of the electron beam is discussed in this paper. Future particle accelerators such as eRHIC and ILC require high brightness, high current polarized electrons Recently, using a superlattice crystal, the maximum polarization of 95% was reached. Activation with Cs,O lowers the electron affinity and makes it energetically possible for all the electrons excited in to the conduction band and reach the surface to escape into the vacuum. Presently the polarized electron sources are based on DC gun, such as that at the CEBAF at Jlab. In these devices, the life time of the cathode is extended due to the reduced back bombardment in their UHV conditions. However, the low accelerating gradient of the DC guns lead to poor longitudinal emittance. The higher accelerating gradient of the RF gun generates low emittance beams. Superconducting RF guns combine the excellent vacuum conditions of the DC guns with the higher accelerating gradients of the RF guns and provide potentially a long lived cathode with very low transverse and longitudinal emittance. In our work at BNL, we successfully activated the GaAs. The quantum efficient is 3% at 532 nm and is expected

Quantum efficiency temporal response and lifetime of a GaAs cathode in SRF electron gun

Energy Technology Data Exchange (ETDEWEB)

Wang, E.; Ben-Zvi, I.; Kewisch, J.; Burrill, A.; Rao, T.; Wu, Q.; Holmes, D.

2010-05-23

RF electron guns with a strained super lattice GaAs cathode can generate polarized electron beam of higher brightness and lower emittance than do DC guns, due to their higher field gradient at the cathode's surface. In a normal conducting RF gun, the extremely high vaccum required by these cathodes can not be met. We report on an experiment with a superconducting SRF gun, which can maintain a vacuum of nearly 10-12 torr because of cryo-pumping at the temperature of 4.2K. With conventional activation, we obtained a QE of 3% at 532 nm, with lifetime of nearly 3 days in the preparation chamber. We plan to use this cathode in a 1.3 GHz 1/2 cell SRF gun to study its performance. In addition, we studied the multipacting at the location of cathode. A new model based on the Forkker-Planck equation which can estimate the bunch length of the electron beam is discussed in this paper. Future particle accelerators such as eRHIC and ILC require high brightness, high current polarized electrons Recently, using a superlattice crystal, the maximum polarization of 95% was reached. Activation with Cs,O lowers the electron affinity and makes it energetically possible for all the electrons excited in to the conduction band and reach the surface to escape into the vacuum. Presently the polarized electron sources are based on DC gun, such as that at the CEBAF at Jlab. In these devices, the life time of the cathode is extended due to the reduced back bombardment in their UHV conditions. However, the low accelerating gradient of the DC guns lead to poor longitudinal emittance. The higher accelerating gradient of the RF gun generates low emittance beams. Superconducting RF guns combine the excellent vacuum conditions of the DC guns with the higher accelerating gradients of the RF guns and provide potentially a long lived cathode with very low transverse and longitudinal emittance. In our work at BNL, we successfully activated the GaAs. The quantum efficient is 3% at 532 nm and is

Development of a high power electron beam welding gun with replaceable high voltage feed-through insulators

Energy Technology Data Exchange (ETDEWEB)

Saha, T.K; Mascarenhas, M.; Kandaswamy, E., E-mail: tanmay@barc.gov.in [Power Beam Equipment Design Section, Bhabha Atomic Research Centre, Mumbai (India)

2014-07-01

Ceramic to metal sealed feed-through insulators are commonly used in electron beam welding gun. The above feed-through insulators are susceptible to failure, as the brazing joints in them are not always very strong. Failure in one of these feed-through could render the complete gun unusable. This problem has already been faced in BARC, which led to the development of the electron gun with replaceable feed through insulators. A 24 kW Electron Beam Welding (EBW) gun with indigenous designed replaceable insulators is fabricated in BARC. Emphasis during the design of the gun had been to reduce the use of imported components to zero. This paper describes the design and fabrication of this gun and reports various simulations and tests performed. Beam trajectory of the gun is numerically computed and presented. Weld passes were carried out on stainless steel plates show satisfactory penetrations. (author)

Design of diode electron gun for 250 kW CW klystron

International Nuclear Information System (INIS)

Prasad, M.; Pande, S.A.; Hannurkar, P.R.

2005-01-01

A 250 kW CW klystron at frequencies 350 MHz and 700 MHz is being developed at Centre for Advanced Technology. These klystrons are required for forthcoming project like 100 MeV proton Linac for Spallation Neutron Source (SNS) as a main rf sources. In order to develop klystrons, we have designed the diode electron gun, which delivers more than 10 A beam current at 50 kV. This paper describes the simulation results of electron gun with computer code EGUN. (author)

High Brightness Electron Guns for Next-Generation Light Sources and Accelerators

International Nuclear Information System (INIS)

H. Bluem; M.D. Cole; J. Rathke; T. Schultheiss; A.M.M. Todd; I. Ben-Zvi; T. Srinivasan-Rao; P. Colestock; D.C. Nguyen; R.L. Wood; L. Young; D. Janssen; J. Lewellen; G. Neil; H.L. Phillips; J.P. Preble

2004-01-01

Advanced Energy Systems continues to develop advanced electron gun and injector concepts. Several of these projects have been previously described, but the progress and status of each will be updated. The project closest to completion is an all superconducting RF (SRF) gun, being developed in collaboration with the Brookhaven National Laboratory, that uses the niobium of the cavity wall itself as the photocathode material. This gun has been fabricated and will shortly be tested with beam. The cavity string for a closely-coupled DC gun and SRF cavity injector that is expected to provide beam quality sufficient for proposed ERL light sources and FELs will be assembled at the Jefferson Laboratory later this year. We are also collaboration with Los Alamos on a prototype CW normal-conducting RF gun with similar performance, that will undergo thermal testing in late 2004. Another CW SRF gun project that uses a high quantum efficiency photocathode, similar to the FZ-Rossendorf approach, has just begun. Finally, we will present the RF design and cold test results for a fully axisymmetric, ultra-high-brightness x-band RF gun

Design of spherical electron gun for ultra high frequency, CW power inductive output tube

International Nuclear Information System (INIS)

Kaushik, Meenu; Joshi, L. M.

2016-01-01

Inductive Output Tube (IOT) is an amplifier that usually operates in UHF range. It is an electron tube whose basic structure is similar to conventional vacuum devices. This device is widely used in broadcast applications but is now being explored for scientific applications also specifically, particle accelerators and fusion plasma heating purposes. The paper describes the design approach of a spherical gridded electron gun of a 500 MHz, 100 kW CW power IOT. The electron gun structure has been simulated and optimized for operating voltage and current of 40kV and 3.5 A respectively. The electromagnetic analysis of this spherical electron gun has been carried out in CST and TRAK codes.

Design of spherical electron gun for ultra high frequency, CW power inductive output tube

Energy Technology Data Exchange (ETDEWEB)

Kaushik, Meenu, E-mail: mkceeri@gmail.com; Joshi, L. M., E-mail: lmj1953@gmail.com [Microwave Tubes Division, CSIR-Central Electronics Engineering Research Institute (CEERI), Pilani, Rajasthan (India); Academy of Scientific and Innovative Research (AcSIR), New Delhi (India)

2016-03-09

Inductive Output Tube (IOT) is an amplifier that usually operates in UHF range. It is an electron tube whose basic structure is similar to conventional vacuum devices. This device is widely used in broadcast applications but is now being explored for scientific applications also specifically, particle accelerators and fusion plasma heating purposes. The paper describes the design approach of a spherical gridded electron gun of a 500 MHz, 100 kW CW power IOT. The electron gun structure has been simulated and optimized for operating voltage and current of 40kV and 3.5 A respectively. The electromagnetic analysis of this spherical electron gun has been carried out in CST and TRAK codes.

Electron bunch structure in energy recovery linac with high-voltage dc photoelectron gun

Directory of Open Access Journals (Sweden)

Y. M. Saveliev

2016-09-01

Full Text Available The internal structure of electron bunches generated in an injector line with a dc photoelectron gun is investigated. Experiments were conducted on the ALICE (accelerators and lasers in combined experiments energy recovery linac at Daresbury Laboratory. At a relatively low dc gun voltage of 230 kV, the bunch normally consisted of two beamlets with different electron energies, as well as transverse and longitudinal characteristics. The beamlets are formed at the head and the tail of the bunch. At a higher gun voltage of 325 kV, the beam substructure is much less pronounced and could be observed only at nonoptimal injector settings. Experiments and computer simulations demonstrated that the bunch structure develops during the initial beam acceleration in the superconducting rf booster cavity and can be alleviated either by increasing the gun voltage to the highest possible level or by controlling the beam acceleration from the gun voltage in the first accelerating structure.

Pierce-Wiggler electron beam system for 250 GHz GYRO-BWO: Final report

International Nuclear Information System (INIS)

Pirkle, D.R.; Alford, C.W.; Anderson, M.H.; Garcia, R.F.; Legarra, J.R.; Nordquist, A.L.

1989-01-01

This final report summarizes the design and performance of the VUW-8028 Pierce-Wiggler electron beam systems, which can be used to power high frequency gyro-BWO's. The operator's manual for this gyro-BWO beamstick is included as appendix A. Researchers at Lawrence Livermore National Laboratory (LLNL) are developing a gyro-BWO with a center frequency of 250 GHz, 6% bandwidth, and 10 kV peak output power. The gyro-BWO will be used to drive a free electron laser amplifier at LLNL. The electron beam requirements of the gyro-BWO application are: Small beam size, .100 inch at 2500 gauss axial magnetic field; a large fraction of the electron energy in rotational velocity; ability to vary the electrons' axial velocity easily, for electronic tuning; and low velocity spread i.e. little variation in the axial velocities of the electrons in the interaction region. 1 ref., 13 figs

Numerical simulations of the thermionic electron gun for electron-beam welding and micromachining

Czech Academy of Sciences Publication Activity Database

Jánský, Pavel; Zlámal, J.; Lencová, Bohumila; Zobač, Martin; Vlček, Ivan; Radlička, Tomáš

2009-01-01

Roč. 84, č. 2 (2009), s. 357-362 ISSN 0042-207X R&D Projects: GA AV ČR IAA100650805 Institutional research plan: CEZ:AV0Z20650511 Keywords : Numerical simulation * Thermionic emission * Electron gun Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.975, year: 2009

Investigation on the optimal magnetic field of a cusp electron gun for a W-band gyro-TWA

Science.gov (United States)

Zhang, Liang; He, Wenlong; Donaldson, Craig R.; Cross, Adrian W.

2018-05-01

High efficiency and broadband operation of a gyrotron traveling wave amplifier (gyro-TWA) require a high-quality electron beam with low-velocity spreads. The beam velocity spreads are mainly due to the differences of the electric and magnetic fields that the electrons withstand the electron gun. This paper investigates the possibility to decouple the design of electron gun geometry and the magnet system while still achieving optimal results, through a case study of designing a cusp electron gun for a W-band gyro-TWA. A global multiple-objective optimization routing was used to optimize the electron gun geometry for different predefined magnetic field profiles individually. Their results were compared and the properties of the required magnetic field profile are summarized.

The design of an electron gun switchable between immersed and Brillouin flowa)

Science.gov (United States)

Becker, R.; Kester, O.

2012-02-01

An electron gun, which can be switched from immersed flow to Brillouin flow during operation, may have advantages for charge breeders as well as for electron beam ion sources and traps (EBISTs). For EBISTs this allows to change the current density according to the repetition frequency and charge state, for charge breeders and EBISTs a lower current density in immersed flow provides higher acceptance for injected ions, while the higher current density in Brillouin flow results in shorter breeding times and a lower emittance for the extracted beam. Therefore, we have designed such a gun for an EBIS with 5 T central magnetic field and without the use of iron and moving the gun. The gun was placed in the axial fringing field of the 5 T solenoid in such a position that a gate valve can be placed between the gun and the cryostat to allow for simple maintenance. The field at the cathode surface turned out to be only 0.05 T, which is not enough to focus 50 A/cm2 at a few kV. However, if a small normal conducting solenoid is placed over the vacuum tube in position of the gun, a field of 0.1 T may be obtained. With this the use of LaB6 as cathode material results in a magnetic compression of 44 and therewith in a focused current density in the trap region of more than 2000 A/cm2. By reversing the current in the gun solenoid the cathode field can easily compensated to zero. By proper design of the electrodes and the compression region, the gun will be able to deliver a beam in Brillouin flow. While this is interesting by itself - remember the "super-compression" reported on CRYEBIS-I - any magnetic field between zero and the value for immersed flow will result in an electron beam with a wide range of adjustable high current densities. The design tools used have been INTMAG(C) for the calculation of magnetic fields, EGN2(C) for the simulation of the gun and ANALYSE(C) for detailed analysis of the results (for more information see www.egun-igun.com).

The design of an electron gun switchable between immersed and Brillouin flow.

Science.gov (United States)

Becker, R; Kester, O

2012-02-01

An electron gun, which can be switched from immersed flow to Brillouin flow during operation, may have advantages for charge breeders as well as for electron beam ion sources and traps (EBISTs). For EBISTs this allows to change the current density according to the repetition frequency and charge state, for charge breeders and EBISTs a lower current density in immersed flow provides higher acceptance for injected ions, while the higher current density in Brillouin flow results in shorter breeding times and a lower emittance for the extracted beam. Therefore, we have designed such a gun for an EBIS with 5 T central magnetic field and without the use of iron and moving the gun. The gun was placed in the axial fringing field of the 5 T solenoid in such a position that a gate valve can be placed between the gun and the cryostat to allow for simple maintenance. The field at the cathode surface turned out to be only 0.05 T, which is not enough to focus 50 A∕cm(2) at a few kV. However, if a small normal conducting solenoid is placed over the vacuum tube in position of the gun, a field of 0.1 T may be obtained. With this the use of LaB(6) as cathode material results in a magnetic compression of 44 and therewith in a focused current density in the trap region of more than 2000 A∕cm(2). By reversing the current in the gun solenoid the cathode field can easily compensated to zero. By proper design of the electrodes and the compression region, the gun will be able to deliver a beam in Brillouin flow. While this is interesting by itself--remember the "super-compression" reported on CRYEBIS-I--any magnetic field between zero and the value for immersed flow will result in an electron beam with a wide range of adjustable high current densities. The design tools used have been INTMAG(C) for the calculation of magnetic fields, EGN2(C) for the simulation of the gun and ANALYSE(C) for detailed analysis of the results (for more information see www.egun-igun.com).

Electron Gun for Computer-controlled Welding of Small Components

Czech Academy of Sciences Publication Activity Database

Dupák, Jan; Vlček, Ivan; Zobač, Martin

2001-01-01

Roč. 62, 2-3 (2001), s. 159-164 ISSN 0042-207X R&D Projects: GA AV ČR IBS2065015 Institutional research plan: CEZ:AV0Z2065902 Keywords : Electron beam-welding machine * Electron gun * Computer- control led beam Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.541, year: 2001

Development of Field-Emission Electron Gun from Carbon Nanotubes

CERN Document Server

Hozumi, Y

2004-01-01

Aiming to use a narrow energy-spread electron beam easily and low costly on injector electron guns, we have been tested field emission cathodes of carbon nanotubes (CNTs). Experiments for these three years brought us important suggestions and a few rules of thumb. Now at last, anode current of 3.0 [A/cm2

Electron beam gun with kinematic coupling for high power RF vacuum devices

Science.gov (United States)

Borchard, Philipp

2016-11-22

An electron beam gun for a high power RF vacuum device has components joined by a fixed kinematic coupling to provide both precise alignment and high voltage electrical insulation of the components. The kinematic coupling has high strength ceramic elements directly bonded to one or more non-ductile rigid metal components using a high temperature active metal brazing alloy. The ceramic elements have a convex surface that mates with concave grooves in another one of the components. The kinematic coupling, for example, may join a cathode assembly and/or a beam shaping focus electrode to a gun stem, which is preferably composed of ceramic. The electron beam gun may be part of a high power RF vacuum device such as, for example, a gyrotron, klystron, or magnetron.

An injector system of a NDZ-20 medical electron linear accelerator

International Nuclear Information System (INIS)

Wang Houwen; Lai Qiji; Zhu Yizhang; Yang Fangxin

1987-01-01

The structure and characteristic of an injector system of a NDZ-20 medical electron linear accelerator are described. A bombarded type of Pierce electron gun is used. There are pre-focusing coil, deflecting coil, steering coil and beam pulse lead cutting coil in drift tube region. They control electron beam efficiently for ARC, ADC and BLC of the accelerator. ARC and ADC can increase stability and reliability of the accelerator operation, and BLC improves energy spectrum of the back feed accelerator

Design of the electron gun for the INS-ES linac

International Nuclear Information System (INIS)

Hashimoto, Yoshinori; Takeda, Yasuhiro; Yoshida, Katsuhide

1993-01-01

We are preparing a new electron gun for the INS-ES linac. Two cathode-wehnelt assemblies using dispenser cathode Y-646E (EIMAC) have been designed with the computer simulation program EGUN by W.B. Herrmannsfeldt. The acceleration voltage and the peak beam current is 100 kV and 1.0 A, respectively, with a pulse width of 1.5 μsec. The different point of the guns is the angle of wehnelt to the beam axis; one is 67.5deg and the other is 90deg. Both guns have almost the same beam characteristics: The beam radius is 1.95 mm and the maximum beam spread is 2.8 mrad at 186 mm from the cathode. (author)

An angular selective electron gun for the KATRIN experiment

Energy Technology Data Exchange (ETDEWEB)

Zacher, Michael; Ortjohann, Hans-Werner; Steinbrink, Nicholas; Josten, Lorenz; Hannen, Volker; Weinheimer, Christian; Winzen, Daniel [Westfaelische Wilhelms-Universitaet, Muenster (Germany); Collaboration: KATRIN-Collaboration

2013-07-01

The KArlsruhe TRItium Neutrino experiment aims for a measurement of the electron anti-neutrino mass with a sensitivity of 200 meV/c{sup 2} (95% C.L.) by analysing the endpoint region of the tritium β-decay. The main spectrometer (MAC-E filter type, 23m length) is one of the central parts of the experiment, featuring an energy resolution of Δ E<1 eV. For commissioning of the spectrometer a well defined electron source is needed that allows to determine the transmission characteristics and compare the electromagnetic properties to simulations. For this purpose an angular selective electron gun was developed. A pulsed UV-Laser produces electrons via the photo-electric effect, which are then accelerated electrostatically in a magnetic field. It features a small energy spread, a sharp selectable emission angle and covers the whole magnetic flux tube of KATRIN. By that, the characteristics of the spectrometer can be investigated with high precision. The time structure of the electron pulses allows time of flight measurements, offering enhanced sensitivity. The talk gives an overview about the e-gun design and its properties.

Analysis of thermionic DC electron gun for 125 MeV linac

International Nuclear Information System (INIS)

Kanno, K.; Sato, Isamu; Sato, K.

2000-01-01

The beam trace calculation for the 100 kV thermionic DC electron gun with EIMAC 646E cathode, which is currently used for the 125 MeV linac at Nihon University, has been performed using EGUN code. The result showed a strong focus of the beam at the exit of the anode. A better geometry of the gun has been investigated by varying the shape of the wehnelt electrode. Also the trace calculation has been performed for the case of EIMAC 646B, which showed a considerably small emittance compared with that estimated for the present gun. (author)

Analysis of thermionic DC electron gun for 125 MeV linac

Energy Technology Data Exchange (ETDEWEB)

Kanno, K. [Graduate School of Science and Technology, Nihon Univ., Funabashi, Chiba (Japan); Sato, Isamu; Sato, K. [Nihon Univ., Funabashi, Chiba (Japan). Atomic Energy Research Inst] [and others

2000-07-01

The beam trace calculation for the 100 kV thermionic DC electron gun with EIMAC 646E cathode, which is currently used for the 125 MeV linac at Nihon University, has been performed using EGUN code. The result showed a strong focus of the beam at the exit of the anode. A better geometry of the gun has been investigated by varying the shape of the wehnelt electrode. Also the trace calculation has been performed for the case of EIMAC 646B, which showed a considerably small emittance compared with that estimated for the present gun. (author)

Fabrication and description of a cold cathode electron gun

International Nuclear Information System (INIS)

Sari, A.H.; Ghorannevis, M.; Hantehzadeh, M.R.; Yousefi, M.R.

2003-01-01

In this study the structure and schematic configuration of a cold cathode electron gun has been shown, which use obstructed discharge for electron producing. This type of discharge and mechanism of secondary electron emission by ions and fast neutral interaction have been described. The experiment starts in pressure of 1*10 -3 torr, in existence of helium gas. A negative DC voltage apply to a concave cathode up to -20 k V which determine electron energy

Low-cost electron-gun pulser for table-top maser experiments

Science.gov (United States)

Grinberg, V.; Jerby, E.; Shahadi, A.

1995-04-01

A simple 10 kV electron-gun pulser for small-scale maser experiments is presented. This low-cost pulser has operated successfully in various table-top cyclotron-resonance maser (CRM) and free-electron maser (FEM) experiments. It consists of a low-voltage capacitor bank, an SCR control circuit and a transformer bank (car ignition coils) connected directly to the e-gun. The pulser produces a current of 3 A at 10 kV voltage in a Gaussian like shape of 1 ms pulse width. The voltage sweep during the pulse provides a useful tool to locate resonances of CRM and FEM interactions. Analytical expressions for the pulser design and experimental measurements are presented.

A device for electron gun emittance measurement

International Nuclear Information System (INIS)

Aune, B.; Corveller, P.; Jablonka, M.; Joly, J.M.

1985-05-01

In order to improve the final emittance of the beam delivered by the ALS electron linac a new gun is going to be installed. To measure its emittance and evaluate the contribution of different factors to emittance growth we have developed an emittance measurement device. We describe the experimental and mathematical procedure we have followed, and give some results of measurements

Equilibrium double layers in extended Pierce diodes

International Nuclear Information System (INIS)

Ciubotariu-Jassy, C.I.

1992-01-01

The extended Pierce diode is similar to the standard (or classical) Pierce diode, but has passive circuit elements in place of the short circuit between the electrodes. This device is important as an approximation to real bounded plasma systems. It consists of two parallel plane electrodes (an emitter located at x=0 and a collector located at x=l) and a collisionless cold electron beam travelling between them. The electrons are neutralized by a background of comoving massive ions. This situation is analysed in this paper and new equilibrium double layer (DL) plasma structures are obtained. (author) 6 refs., 3 figs

An ultrafast electron microscope gun driven by two-photon photoemission from a nanotip cathode

International Nuclear Information System (INIS)

Bormann, Reiner; Strauch, Stefanie; Schäfer, Sascha; Ropers, Claus

2015-01-01

We experimentally and numerically investigate the performance of an advanced ultrafast electron source, based on two-photon photoemission from a tungsten needle cathode incorporated in an electron microscope gun geometry. Emission properties are characterized as a function of the electrostatic gun settings, and operating conditions leading to laser-triggered electron beams of very low emittance (below 20 nm mrad) are identified. The results highlight the excellent suitability of optically driven nano-cathodes for the further development of ultrafast transmission electron microscopy

Design of a high-brightness, high-duty factor photocathode electron gun

International Nuclear Information System (INIS)

Lehrman, I.S.; Birnbaum, I.A.; Fixler, S.Z.; Heuer, R.L.; Siddiqi, S.; Sheedy, E.; Ben-Zvi, I.; Batchelor, K.; Gallardo, J.C.; Kirk, H.G.; Srinivasan-Rao, T.; Warren, G.D.

1991-09-01

The proposed UV-FEL user's facility at Brookhaven National Laboratory will require a photocathode gun capable of producing short (< 6 psec) bunches of electrons in high repetition rates (5 kHz), low energy spread (< 1.5.%), a peak current of 300 A (after compression) and a total bunch charge of up to 2 nC. At the highest charge the normalized transverse emittance should be less than 7 π mm-mrad. We are presently designing a gun that is expected to exceed these requirements. This gun will consist of 3 1/2 cells, constructed of GlidCop-15, an aluminum oxide dispersion strengthened copper alloy. The gun will be capable of operating at duty factors in excess of 1%. Extensive beam dynamics studies of the gun were used to determine the effect of varying the length of the first cell, shaping the apertures between cells, and increasing the number of cells. In addition, a detailed thermal and mechanical study of the gun was performed to ensure that the thermal stresses were well within the allowable limits and that copper erosion of the water channels would not occur

Voltage-pulse generator for electron gun

International Nuclear Information System (INIS)

Korenev, S.A.; Enchevich, I.B.; Mikhov, M.K.

1987-01-01

A voltage-pulse generator with combined capacitive and inductive storage devices of an electron gun is described. The current interrupter is a hydrogen thyratron (TGI1-100/8, TGI1-500/16, or TGI1-1000/25) installed in a short magnetic lens. The current interruption time of the thyratrons is 100-300 nsec. When the capacitive storage device is charged to 1 kV, a voltage pulse with an amplitude of 25 kV is obtained at the load

Tattoos and Piercing

Science.gov (United States)

... Looking and feeling your best Tattoos and piercing Tattoos and piercing Some people think piercings and tattoos ... surgery if you want to close the hole. Tattoos top How about henna? You may have seen ...

Heating filament system of a Mig-type electron gun for a 35 GHz, 100 k W gyrotron

International Nuclear Information System (INIS)

Patire Junior, H.; Barroso, J.J.; Spassovsky, I.P.; Rossi, J.O.

1993-01-01

Cathode temperature tests of a Mig-type electron gun have been performed to determine the temperature of the electron emitting surface as a function of heater voltage and current. The test have been conducted partway through the construction phase of the gun as a means to minimize both the necessary heater input power and to reduce radiating of gun components. (author)

Study of the Welding Electron Gun Optical Properties for Work Piece Imaging

Czech Academy of Sciences Publication Activity Database

Vlček, Ivan

2009-01-01

Roč. 44, 5-6 (2009), s. 70-72 ISSN 0861-4717 R&D Projects: GA AV ČR KAN300100702 Institutional research plan: CEZ:AV0Z20650511 Keywords : electron beam welding * electron gun * electron optics design Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

Pulsed WIP electron gun. Final report: design phase 1 x 70 cm cooled WIP electron gun, 1 December 1978--2 February 1979

International Nuclear Information System (INIS)

Wakalopulos, G.; Gresko, L.

1979-01-01

Presented here are design criteria for a full scale (70 cm) WIP electron gun system capable of long run operation with the following specifications: foil area approx. 70 x 1 cm, electron beam current density approx. 1 A/cm 2 , pulse length 2 , voltage -150 kV, voltage droop < 10%, Rep rate approx. 10 KHz, power approx. 20 kW, run time approx. 30 min, and jitter approx. 10 μs

Communication: Effects of thermionic-gun parameters on operating modes in ultrafast electron microscopy

Directory of Open Access Journals (Sweden)

Erik Kieft

2015-09-01

Full Text Available Ultrafast electron microscopes with thermionic guns and LaB6 sources can be operated in both the nanosecond, single-shot and femtosecond, single-electron modes. This has been demonstrated with conventional Wehnelt electrodes and absent any applied bias. Here, by conducting simulations using the General Particle Tracer code, we define the electron-gun parameter space within which various modes may be optimized. The properties of interest include electron collection efficiency, temporal and energy spreads, and effects of laser-pulse duration incident on the LaB6 source. We find that collection efficiencies can reach 100% for all modes, despite there being no bias applied to the electrode.

Experimental results from a DC photocathode electron gun for an IR FEL

International Nuclear Information System (INIS)

Kehne, D.; Engwall, D.; Legg, R.; Shinn, M.

1997-01-01

A 350 keV DC photocathode gun capable of delivering the high-brightness CW electron beam necessary for Jefferson Lab's infrared free-electron laser is described. The gun is to be used with a superconducting radiofrequency linac operating at 1.497 GHz and is mode-locked to the 40th subharmonic of the fundamental using a Nd:YLF drive laser. The gun provides 20--25 ps bunches at up to 135 pC/bunch. Experimental measurements of transverse and longitudinal beam properties are presented. Transverse emittance is measured using a slit-wire scanner emittance meter, and energy spread is measured using the slit and a spectrometer magnet. Longitudinal emittance is measured using a combination of sampling aperture, kicker cavity, slit and spectrometer. Measurements for bunch charges of 135 pC are described and compared with simulations

Optimization of a triode-type cusp electron gun for a W-band gyro-TWA

Science.gov (United States)

Zhang, Liang; Donaldson, Craig R.; He, Wenlong

2018-04-01

A triode-type cusp electron gun was optimized through numerical simulations for a W-band gyrotron traveling wave amplifier. An additional electrode in front of the cathode could switch the electron beam on and off instantly when its electric potential is properly biased. An optimal electron beam of current 1.7 A and a velocity ratio (alpha) of 1.12 with an alpha spread of ˜10.7% was achieved when the triode gun was operated at 40 kV.

Pierce instability and bifurcating equilibria

International Nuclear Information System (INIS)

Godfrey, B.B.

1981-01-01

The report investigates the connection between equilibrium bifurcations and occurrence of the Pierce instability. Electrons flowing from one ground plane to a second through an ion background possess a countable infinity of static equilibria, of which only one is uniform and force-free. Degeneracy of the uniform and simplest non-uniform equilibria at a certain ground plan separation marks the onset of the Pierce instability, based on a newly derived dispersion relation appropriate to all the equilibria. For large ground plane separations the uniform equilibrium is unstable and the non-uniform equilibrium is stable, the reverse of their stability properties at small separations. Onset of the Pierce instability at the first bifurcation of equilibria persists in more complicated geometries, providing a general criterion for marginal stability. It seems probable that bifurcation analysis can be a useful tool in the overall study of stable beam generation in diodes and transport in finite cavities

Stability measurements of the electron gun for the KATRIN rear section

Energy Technology Data Exchange (ETDEWEB)

Ebenhoech, Sylvia [Karlsruhe Institute of Technology (KIT) (Germany). Institute for Technical Physics (ITEP), Tritium Laboratory Karlsruhe (TLK); Collaboration: KATRIN-Collaboration

2016-07-01

The aim of the KArlsruhe TRItium Neutrino (KATRIN) experiment is to determine the antineutrino mass with a sensitivity of 0.2 eV (90 % C.L.) by high-precision spectroscopy close to the tritium beta decay endpoint at 18.6 keV. To achieve the sensitivity aim both statistical and systematic uncertainties must be minimized. One contribution to the systematic error are uncertainties in the column density of the tritium source or in the source activity. In order to detect and monitor changes in the tritium source the Rear Section, which is integrated at the rear end of the KATRIN setup, is used. The Rear Section includes an angular selective electron gun (e-gun) based on the photoelectric effect. With the e-gun it will be possible e.g. to achieve a precise calibration of the column source density. To achieve the requirements on the e-gun a stable UV light source is essential to produce photoelectrons. The presentation focuses on the setup of the e-gun and intensity stability measurements of the UV light source setup.

High-brightness electron guns for linac-based light sources

International Nuclear Information System (INIS)

Lewellen, J.W.

2004-01-01

Most proposed linac-based light sources, such as single-pass free-electron lasers and energy-recovery-linacs, require very high-brightness electron beams in order to achieve their design performance. These beam requirements must be achieved not on an occasional basis, but rather must be met by every bunch produced by the source over extended periods of time. It is widely assumed that the beam source will be a photocathode electron gun; the selection of accelerator technique (e.g., dc or rf) for the gun is more dependent on the application.The current state of the art of electron beam production is adequate but not ideal for the first generation of linac-based light sources, such as the Linac Coherent Light Source (LCLS) x-ray free-electron laser (X-FEL). For the next generation of linac-based light sources, an order of magnitude reduction in the transverse electron beam emittance is required to significantly reduce the cost of the facility. This is beyond the present state of the art, given the other beam properties that must be maintained. The requirements for current and future linac-based light source beam sources are presented here, along with a review of the present state of the art. A discussion of potential paths towards meeting future needs is presented at the conclusion.

Cerenkov Radiator Driven by a Superconducting RF Electron Gun

International Nuclear Information System (INIS)

Poole, B.R.; Harris, J.R.

2011-01-01

The Naval Postgraduate School (NPS), Niowave, Inc., and Boeing have recently demonstrated operation of the first superconducting RF electron gun based on a quarter wave resonator structure. In preliminary tests, this gun has produced 10 ps long bunches with charge in excess of 78 pC, and with beam energy up to 396 keV. Initial testing occurred at Niowave's Lansing, MI facility, but the gun and diagnostic beam line are planned for installation in California in the near future. The design of the diagnostic beam line is conducive to the addition of a Cerenkov radiator without interfering with other beam line operations. Design and simulations of a Cerenkov radiator, consisting of a dielectric lined waveguide will be presented. The dispersion relation for the structure is determined and the beam interaction is studied using numerical simulations. The characteristics of the microwave radiation produced in both the short and long bunch regimes will be presented.

Simulations of the ILC Electron Gun and Electron Bunching System

International Nuclear Information System (INIS)

Haakonsen, C.B.; McGill U.

2006-01-01

The International Linear Collider (ILC) is a proposed electron-positron collider, expected to provide insight into important questions in particle physics. A part of the global R and D effort for the ILC is the design of its electron gun and electron bunching system. The present design of the bunching system has two sub-harmonic bunchers, one operating at 108 MHz and one at 433MHz, and two 5-cell 1.3 GHz (L-band) bunchers. This bunching system has previously been simulated using the Phase and Radial Motion in Electron Linear Accelerators (PARMELA) software, and those simulations indicated that the design provides sufficient bunching and acceleration. Due to the complicated dynamics governing the electrons in the bunching system we decided to verify and expand the PARMELA results using the more recent and independent simulation software General Particle Tracer (GPT). GPT tracks the motion and interactions of a set of macro particles, each of which represent a number of electrons, and provides a variety of analysis capabilities. To provide initial conditions for the macro particles, a method was developed for deriving the initial conditions from detailed simulations of particle trajectories in the electron gun. These simulations were performed using the Egun software. For realistic simulation of the L-band bunching cavities, their electric and magnetic fields were calculated using the Superfish software and imported into GPT. The GPT simulations arrived at similar results to the PARMELA simulations for sub-harmonic bunching. However, using GPT it was impossible to achieve an efficient bunching performance of the first L-band bunching cavity. To correct this, the first L-band buncher cell was decoupled from the remaining 4 cells and driven as an independent cavity. Using this modification we attained results similar to the PARMELA simulations. Although the modified bunching system design performed as required, the modifications are technically challenging to implement

Note: Simulation and test of a strip source electron gun.

Science.gov (United States)

Iqbal, Munawar; Islam, G U; Misbah, I; Iqbal, O; Zhou, Z

2014-06-01

We present simulation and test of an indirectly heated strip source electron beam gun assembly using Stanford Linear Accelerator Center (SLAC) electron beam trajectory program. The beam is now sharply focused with 3.04 mm diameter in the post anode region at 15.9 mm. The measured emission current and emission density were 1.12 A and 1.15 A/cm(2), respectively, that corresponds to power density of 11.5 kW/cm(2), at 10 kV acceleration potential. The simulated results were compared with then and now experiments and found in agreement. The gun is without any biasing, electrostatic and magnetic fields; hence simple and inexpensive. Moreover, it is now more powerful and is useful for accelerators technology due to high emission and low emittance parameters.

3D Modeling Activity for Novel High Power Electron Guns at SLAC

International Nuclear Information System (INIS)

Krasnykh, Anatoly

2003-01-01

The next generation of powerful electronic devices requires new approaches to overcome the known limitations of existing tube technology. Multi-beam and sheet beam approaches are novel concepts for the high power microwave devices. Direct and indirect modeling methods are being developed at SLAC to meet the new requirements in the 3D modeling. The direct method of solving of Poisson's equations for the multi-beam and sheet beam guns is employed in the TOPAZ 3D tool. The combination of TOPAZ 2D and EGUN (in the beginning) with MAFIA 3D and MAGIC 3D (at the end) is used in an indirect method to model the high power electron guns. Both methods complement each other to get reliable representation of the beam trajectories. Several gun ideas are under consideration at the present time. The collected results of these simulations are discussed

3D Modeling Activity for Novel High Power Electron Guns at SLAC

CERN Document Server

Krasnykh, Anatoly K

2003-01-01

The next generation of powerful electronic devices requires new approaches to overcome the known limitations of existing tube technology. Multi-beam and sheet beam approaches are novel concepts for the high power microwave devices. Direct and indirect modeling methods are being developed at SLAC to meet the new requirements in the 3D modeling. The direct method of solving of Poisson's equations for the multi-beam and sheet beam guns is employed in the TOPAZ 3D tool. The combination of TOPAZ 2D and EGUN (in the beginning) with MAFIA 3D and MAGIC 3D (at the end) is used in an indirect method to model the high power electron guns. Both methods complement each other to get reliable representation of the beam trajectories. Several gun ideas are under consideration at the present time. The collected results of these simulations are discussed.

Study of beam transverse properties of a thermionic electron gun for application to a compact THz free electron laser

International Nuclear Information System (INIS)

Hu, Tongning; Qin, Bin; Tan, Ping; Chen, Qushan; Yang, Lei; Pei, Yuanji; Li, Ji

2014-01-01

A novel thermionic electron gun adopted for use in a high power THz free electron laser (FEL) is proposed in this paper. By optimization of the structural and radiofrequency (RF) parameters, the physical design of the gun is performed using dynamic calculations. Velocity bunching is used to minimize the bunch's energy spread, and the dynamic calculation results indicate that high quality beams can be provided. The transverse properties of the beams generated by the gun are also analyzed. The novel RF focusing effects of the resonance cavity are investigated precisely and are used to establish emittance compensation, which enables the injector length to be reduced. In addition, the causes of the extrema of the beam radius and the normalized transverse emittance are analyzed and interpreted, respectively, and slice simulations are performed to illustrate how the RF focusing varies along the bunch length and to determine the effects of that variation on the emittance compensation. Finally, by observation of the variations of the beam properties in the drift tube behind the electron gun, prospective assembly scenarios for the complete THz-FEL injector are discussed, and a joint-debugging process for the injector is implemented

Electron gun for formation of two high-current beams

International Nuclear Information System (INIS)

Borisov, A.R.; Zherlitsyn, A.G.; Mel'nikov, G.V.; Shtejn, Yu.G.

1982-01-01

The design of the ''Tonus'' accelerator electron gun for formation of two high-current beams aiming at the production of the maximum beam power and density is described. The results of investigation of two modes of beam formation are presented. In the first variant the beams were produced by means of two plane diodes with 40 mm diameter cathodes made of stainless steel and anodes made of 50 μm thick titanium foil. In the second variant the beams were formed by means of two coaxial diodes with magnetic insulation. In one diode the cathode diameter equals to 74 mm, the anode diameter - 92 mm, in the other diode 16 and 44 mm respectively. Current redistribution in the diodes and its effect on accelerating voltage are investigated. It is shown that the gun permits formation of synchronized two high-current beams, iaving equal electron energied. Wide range current control of both beams is possible

Design and performance of a 30 KV electron gun with ten independent cathodes & a magnetic lens.

Energy Technology Data Exchange (ETDEWEB)

Rudys, Joseph Matthew; Reed, Kim Warren

2006-08-01

Measurements on a 30 kV electron gun with ten independent cathodes, operating in a 6.5 Tesla (T) magnetic field are presented. An earlier paper covered the design of this electron gun [1]. Experimental results are compared to model predictions. Beam current is compared to theoretical space charge limited flow.

Ignition Features of Plasma-Beam Discharge in Gas-Discharge Electron Gun Operation

Directory of Open Access Journals (Sweden)

Valery A. Tutyk

2013-01-01

Full Text Available The current paper presents the results of experimental researches to determine the mode features of plasma-beam discharge (PBD generation by an electron beam injected by a low-vacuum gasdischarge electron gun (LGEG with the cold cathode and hollow anode on the basis of the high-voltage glow discharge and in the range of helium pressure of P ? 10 ÷ 130 Pa. The PBD boundaries and their dependences on parameters of an electron beam are found. The influence of PBD on parameters of low-vacuum gas-discharge electron gun is revealed. It causes an avalanche increase of electron beam current and burning of plasma-beam discharge in the whole space of the vacuum chamber volume and generation of electromagnetic radiation is revealed. Achieved results will be used for implementation of various vacuum technologies in the medium of reaction gas and generated electromagnetic radiation.

Sensitivity of perveance to cathode placement in a low perveance electron gun

International Nuclear Information System (INIS)

Lampel, M.C.; Herrmannsfeld, W.B.; Rand, R.E.; Wang, D.Y.

1985-01-01

The SLAC Electron Trajectory Program (EGUN) has been used to simulate a low perveance electron gun which will produce an 800 mA space charge limited beam at 130 kV. The simulations indicate that axial displacements of the cathode by + or -0.5 mm from its nominal position can produce a factor of two variation in the perveance of the electron gun. This sensitivity is due to the boundary conditions of the electrostatic potential near the cathode. Movement of the cathode relative to a fixed focus electrode produces an enhanced variation of the electric field near the cathode surface over that which occurs when both cathode and electrode are moved together. The simulations are in agreement with experimental data

Body Piercing

Science.gov (United States)

... another metal. You should shop around and check prices at different piercing salons before you decide on ... Rinse tongue or lip piercings after every meal, snack and before bed (4-5 times a day) ...

Developments in the electron gun simulation program, EGUN

International Nuclear Information System (INIS)

Herrmannsfeldt, W.B.

1994-11-01

This paper discusses the developments in the electron gun simulation programs that are based on EGUN with its derivatives and supporting programs. Much of the code development has been inspired by technology changes in computer hardware; the implications of this evolution on EGN2 are discussed. Some examples and a review of the capabilities of the EGUN family are described

Developments in the electron gun simulation program, EGUN

Science.gov (United States)

Herrmannsfeldt, W. B.

1995-07-01

This paper discusses the developments in the electron gun simulation programs that are based on EGUN with its derivatives and supporting programs. Much of the code development has been inspired by technology changes in computer hardware; the implications of this evolution on EGN2 are discussed. Some examples and a review of the capabilities of the EGUN family are described.

Solid state cesium ion guns for surface studies

International Nuclear Information System (INIS)

Souzis, A.E.; Carr, W.E.; Kim, S.I.; Seidl, M.

1990-01-01

Three cesium ion guns covering the energy range of 5--5000 V are described. These guns use a novel source of cesium ions that combine the advantages of porous metal ionizers with those of aluminosilicate emitters. Cesium ions are chemically stored in a solid electrolyte pellet and are thermionically emitted from a porous thin film of tungsten at the surface. Cesium supply to the emitting surface is controlled by applying a bias across the pellet. A total charge of 10.0 C can be extracted, corresponding to greater than 2000 h of lifetime with an extraction current of 1.0 μA. This source is compact, stable, and easy to use, and produces a beam with >99.5% purity. It requires none of the differential pumping or associated hardware necessary in designs using cesium vapor and porous tungsten ionizers. It has been used in ultrahigh-vacuum (UHV) experiments at pressures of -10 Torr with no significant gas load. Three different types of extraction optics are used depending on the energy range desired. For low-energy deposition, a simple space-charge-limited planar diode with a perveance of 1x10 -7 A/V 3/2 is used. Current densities of 10.0 μA/cm 2 at the exit aperture for energies ≤20 V are typical. This type of source provides an alternative to vapor deposition with the advantage of precise flux calibration by integration of the ion current. For energies from 50 to 500 V and typical beam radii of 0.5 to 0.2 mm, a high perveance Pierce-type ion gun is used. This gun was designed with a perveance of 1x10 -9 A/V 3/2 and produces a beam with an effective temperature of 0.35 eV. For the energy range of 0.5 to 5 keV, the Pierce gun is used in conjunction with two Einzel lenses, enabling a large range of imaging ratios to be obtained. Beam radii of 60 to 300 μm are typical for beam currents of 50 nA to 1.0 μA

Investigations and Applications of Field- and Photo-emitted Electron Beams from a Radio Frequency Gun

Energy Technology Data Exchange (ETDEWEB)

Panuganti, SriHarsha [Northern Illinois Univ., DeKalb, IL (United States)

2015-08-01

Production of quality electron bunches using e cient ways of generation is a crucial aspect of accelerator technology. Radio frequency electron guns are widely used to generate and rapidly accelerate electron beams to relativistic energies. In the current work, we primarily study the charge generation processes of photoemission and eld emission inside an RF gun installed at Fermilab's High Brightness Electron Source Laboratory (HBESL). Speci cally, we study and characterize second-order nonlinear photoemission from a Cesium Telluride (Cs₂Te) semiconductor photocathode, and eld emission from carbon based cathodes including diamond eld emission array (DFEA) and carbon nanotube (CNT) cathodes located in the RF gun's cavity. Finally, we discuss the application experiments conducted at the facility to produce soft x-rays via inverse Compton scattering (ICS), and to generate uniformly lled ellipsoidal bunches and temporally shaped electron beams from the Cs₂Te photocathode.

Electron beam characterization of a combined diode rf electron gun

Directory of Open Access Journals (Sweden)

R. Ganter

2010-09-01

Full Text Available Experimental and simulation results of an electron gun test facility, based on pulsed diode acceleration followed by a two-cell rf cavity at 1.5 GHz, are presented here. The main features of this diode-rf combination are: a high peak gradient in the diode (up to 100  MV/m obtained without breakdown conditioning, a cathode shape providing an electrostatic focusing, and an in-vacuum pulsed solenoid to focus the electron beam between the diode and the rf cavity. Although the test stand was initially developed for testing field emitter arrays cathodes, it became also interesting to explore the limits of this electron gun with metallic photocathodes illuminated by laser pulses. The ultimate goal of this test facility is to fulfill the requirements of the SwissFEL project of Paul Scherrer Institute [B. D. Patterson et al., New J. Phys. 12, 035012 (2010NJOPFM1367-263010.1088/1367-2630/12/3/035012]; a projected normalized emittance below 0.4  μm for a charge of 200 pC and a bunch length of less than 10 ps (rms. A normalized projected emittance of 0.23  μm with 13 pC has been measured at 5 MeV using a Gaussian laser longitudinal intensity distribution on the photocathode. Good agreements with simulations have been obtained for different electron bunch charge and diode geometries. Emittance measurements at a bunch charge below 1 pC were performed for different laser spot sizes in agreement with intrinsic emittance theory [e.g. 0.54  μm/mm of laser spot size (rms for Cu at 274 nm]. Finally, a projected emittance of 1.25+/-0.2  μm was measured with 200 pC and 100  MV/m diode gradient.

Design of Control System Device for Electron Gun Power Supply of 350 keV/10 mA Electron Beam Machine

International Nuclear Information System (INIS)

Eko Priyono; Budi Santosa; Taxwim

2003-01-01

The electron gun power supply control system of electron beam machine has been designed. Using this design regulator device for the electron gun power supply will be constructed. This regulator device was designed that it can be operated manually or automatically. Beside that, this was also provided with the safety system which is useful to scram the MBE when something wrong happened. The main components of the device are remote data communication system using infra red and fiber optic module, DC motor driver system, regulated transformer coupled by DC motor and operation panel system. (author)

In Vitro Adherence of Oral Bacteria to Different Types of Tongue Piercings

OpenAIRE

Borges, Lucas Pereira; Ferreira-Filho, Julio Cesar Campos; Martins, Julia Medeiros; Alves, Caroline Vieira; Santiago, Bianca Marques; Valen?a, Ana Maria Gondim

2016-01-01

The purpose of this work was to verify in vitro adherence of E. corrodens and S. oralis to the surface of tongue piercings made of surgical steel, titanium, Bioplast, and Teflon. For this, 160 piercings were used for the count of Colony Forming Units (CFU) and 32 piercings for analysis under scanning electron microscopy. Of these, 96 (24 of each type) were individually incubated in 5?mL of BHI broth and 50??L of inoculum at 37?C/24?h. The other 96 piercings formed the control group and were i...

Development of a novel thermionic RF electron gun applied on a compact THz-FEL facility

Science.gov (United States)

Hu, T. N.; Pei, Y. J.; Qin, B.; Liu, K. F.; Feng, G. Y.

2018-04-01

The current requirements from civil and commercial applications lead to the development of compact free-electron laser (FEL)-based terahertz (THz) radiation sources. A picosecond electron gun plays an important role in an FEL-THz facility and attracts significant attention, as machine performance is very sensitive to initial conditions. A novel thermionic gun with an external cathode (EC) and two independently tunable cavities (ITCs) has been found to be a promising alternative to conventional electron sources due to its remarkable characteristics, and correspondingly an FEL injector can achieve a balance between a compact layout and high brightness benefitting from the velocity bunching properties and RF focusing effects in the EC-ITC gun. Nevertheless, the EC-ITC gun has not been extensively examined as part of the FEL injector in the past years. In this regard, to fill this gap, a development focusing on the experimental setup of an FEL injector based on an EC-ITC gun is described in detail. Before assembly, dynamic beam simulations were performed to investigate the optimal mounting position for the Linac associated with the focusing coils, and a suitable radio-frequency (RF) system was established based on a power coupling design and allocation. The testing bench proved to be fully functional through basic experiments using typical diagnostic approaches for estimating primary parameters. Associated with dynamic beam calculations, a performance evaluation for an EC-ITC gun was established while providing indirect testing results for an FEL injector.

Femtosecond electron bunches from an RF-gun

International Nuclear Information System (INIS)

Rimjaem, Sakhorn; Farias, Ruy; Thongbai, Chitrlada; Vilaithong, Thiraphat; Wiedemann, Helmut

2004-01-01

Sub-picosecond electron pulses become a tool of increasing importance to study dynamics at an atomic level. Such electron pulses can be used directly or be converted into intense coherent far infrared radiation or equally short X-ray pulses. In principle, sub-picosecond electron pulses can be obtained in large, high-energy electron linear accelerator systems by repeatedly applying an energy slew and magnetic compression. Another process is the production of short electron pulses at low energies from an RF-gun with a thermionic cathode together with a bunch compressing α-magnet. In this paper, we present a systematic analysis of capabilities and limits of sub-picosecond electron pulses from such a source. We discuss particular parameter choices as well as the impact of geometric and electric specifications on the 6-dimensional phase space electron distribution. Numerical beam simulations with the computer code PARMELA are performed including effects and limitations due to space charge forces. While the production of femtosecond electron bunches is of primary concern, we also consider the preservation of such short bunches along a beam transport line

Design and modelling of a 5 MeV radio frequency electron gun

International Nuclear Information System (INIS)

Batchelor, K.; Sheehan, J.; Woodle, M.

1988-01-01

The Accelerator Test Facility (ATF) at Brookhaven National Laboratory is a linac-laser complex for research into laser acceleration and for the generation of coherent radiation from electron beams. In order to achieve the design 50 MeV output emittance (γσ/sub x/σ/sub x/') of less than 3 /times/ 10/sup /minus/5/ m rad a high brightness electron gun is required. This paper describes computations and measurements made on a full scale brass model of a 1-1/2 cell, π-mode, resonant, disc loaded, radiofrequency gun structure which has been designed for this purpose. 7 refs., 9 figs., 6 tabs

Time-dependent plasma behavior triggered by a pulsed electron gun under conditions of beam-plasma-discharge

International Nuclear Information System (INIS)

Szuszczewicz, E.P.; Lin, C.S.

1982-01-01

This chapter reports on experiments whose purpose was to simulate spaceborne applications of energetic electron guns while exploring the ''in situ'' diagnostics of time-dependent beam-plasma behavior under pulsed electron gun conditions. Beam-plasma-discharge (BPD), the BPD afterglow that exists after gun-pulse termination, and the plasma decay process are considered. It is concluded that there is a rapid enhancement in plasma density as the gas turns on; that during the pulse-ON time a quasi-steady-state BPD can be maintained with characteristics identical with its dc counterpart; that in the period immediately following gun-pulse termination the plasma loss process is dominated by cross-field radial diffusion; and that the afterglow plasma is within + or -10% of being an isodensity contour

Operating experience with the polarized electron gun at SLAC

International Nuclear Information System (INIS)

Alguard, M.J.; Baum, G.; Clendenin, J.E.; Hughes, V.W.; Lubell, M.S.; Miller, R.H.; Raith, W.; Schuler, K.P.; Sodja, J.

1977-03-01

During the two years of operation of the SLAC Polarized Electron Gun (PEGGY), the electron intensity delivered to the target has increased from 7 x 10 7 e - /pulse to 1 x 10 9 e - /pulse. The polarization is 0.85 with no measurable degradation caused by acceleration through the linear accelerator. The predominant cause of downtime is replenishment of lithium, which now averages 43 hours. The lifetime of a lithium load is about 175 hours

Design and implementation of a fs-resolved transmission electron microscope based on thermionic gun technology

Energy Technology Data Exchange (ETDEWEB)

Piazza, L., E-mail: luca.piazza@epfl.ch [Laboratory for Ultrafast Microscopy and Electron Scattering (LUMES), ICMP, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne (Switzerland); Masiel, D.J. [Integrated Dynamic Electron Solutions, Inc., 455 Bolero Drive, Danville, CA 94526 (United States); LaGrange, T.; Reed, B.W. [Condensed Matter and Materials Division Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, P.O. Box 808, L-356, Livermore, CA 94550 (United States); Barwick, B. [Department of Physics, Trinity College, 300 Summit St., Hartford, CT 06106 (United States); Carbone, Fabrizio [Laboratory for Ultrafast Microscopy and Electron Scattering (LUMES), ICMP, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne (Switzerland)

2013-09-23

Highlights: • We present the implementation of a femtosecond-resolved ultrafast TEM. • This is the first ultrafast TEM based on a thermionic gun geometry. • An additional condenser lens has been used to maximize the electron count. • We achieved a time resolution of about 300 fs and an energy resolution of 1 eV. - Abstract: In this paper, the design and implementation of a femtosecond-resolved ultrafast transmission electron microscope is presented, based on a thermionic gun geometry. Utilizing an additional magnetic lens between the electron acceleration and the nominal condenser lens system, a larger percentage of the electrons created at the cathode are delivered to the specimen without degrading temporal, spatial and energy resolution significantly, while at the same time maintaining the femtosecond temporal resolution. Using the photon-induced near field electron microscopy effect (PINEM) on silver nanowires the cross-correlation between the light and electron pulses was measured, showing the impact of the gun settings and initiating laser pulse duration on the electron bunch properties. Tuneable electron pulses between 300 fs and several ps can be obtained, and an overall energy resolution around 1 eV was achieved.

A tapered multi-gap multi-aperture pseudospark-sourced electron gun based X-band slow wave oscillator

Science.gov (United States)

Kumar, N.; Lamba, R. P.; Hossain, A. M.; Pal, U. N.; Phelps, A. D. R.; Prakash, R.

2017-11-01

The experimental study of a tapered, multi-gap, multi-aperture pseudospark-sourced electron gun based X-band plasma assisted slow wave oscillator is presented. The designed electron gun is based on the pseudospark discharge concept and has been used to generate a high current density and high energy electron beam simultaneously. The distribution of apertures has been arranged such that the field penetration potency inside the backspace of the hollow-cathode is different while passing through the tapered gap region. This leads to non-concurrent ignition of the discharge through all the channels which is, in general, quite challenging in the case of multi-aperture plasma cathode electron gun geometries. Multiple and successive hollow cathode phases are reported from this electron gun geometry, which have been confirmed using simulations. This geometry also has led to the achievement of ˜71% fill factor inside the slow wave oscillator for an electron beam of energy of 20 keV and a beam current density in the range of 115-190 A/cm2 at a working argon gas pressure of 18 Pa. The oscillator has generated broadband microwave output in the frequency range of 10-11.7 GHz with a peak power of ˜10 kW for ˜50 ns.

Developments in the electron gun simulation program, EGUN

International Nuclear Information System (INIS)

Herrmannsfeldt, W.B.

1995-01-01

This paper discusses the developments in the electron gun simulation programs that are based on EGUN with its derivatives and supporting programs. Much of the code development has been inspired by technology changes in computer hardware; the implications of this evolution on EGN2 are discussed. Some examples and a review of the capabilities of the EGUN family are described. copyright 1995 American Institute of Physics

Thermal and mechanical study of a MIG-type electron gun for a 31 GHz, 100 k W gyrotron

International Nuclear Information System (INIS)

Patire Junior, H.; Barroso, J.J.

1994-01-01

A thermal and mechanical study of a MIG-type electron gun has been made to determine the temperature distribution in all the gun elements as a function of the input heater power. Appropriate materials were selected to minimize both the conduction and radiation thermal losses. The electron emitting surface operates at an average temperature of 1000 0 C with 374 W input power in the heating filament system. The purpose of the present study is to reduce the input heater power while keeping the required operating cathode temperature and to improve the gun design from a constructional point of view aiming at extending the capabilities of the electron gun. A thermal software has been used by considering the operation conditions taking into account external convection by forced air and thermal radiation transfer between the electrodes of the gun. (author). 5 refs, 4 figs, 1 tab

A cold cathode of a gas-discharge electron-ion gun

International Nuclear Information System (INIS)

1974-01-01

A cold cathode of a gas-discharge electron-ion gun is constructed in order to continuously replace the eroded material by feeding a wire or a set of coaxial cylinders in the spot where the ions hit the cathode. In this way, the form of the cathode and the electric-field configuration is preserved which guarantees the conservation of a sharp narrow electron beam profile

Amorphous NEA Silicon Photocathodes - A Robust RF Gun Electron Source. Final Report

International Nuclear Information System (INIS)

Mulhollan, Gregory A.

2009-01-01

Amorphous silicon (a-Si) has been shown to have great promise as a negative electron affinity visible wavelength photocathode suitable for radio frequency (RF) gun systems. The specific operating wavelength can be shifted by growing it as a germanium alloy (a-Si(1-x)Ge(x)) rather than as pure silicon. This class of photoemitters has been shown to possess a high degree of immunity to charged particle flux. Such particle flux can be a significant problem in the operation of other photocathodes in RF gun systems. Its emission characteristics in the form of current per unit area, or current density, and emission angle, or beam spread are well matched for use in RF guns. Photocathodes made of a-Si can be fabricated on a variety of substrates including those most commonly employed in RF gun systems. Such photocathodes can be made for operation in either transmission or reflection mode. By growing them utilizing radio frequency plasma enhanced chemical vapor deposition, the unit cost is quite low, the quality is high and it is straightforward to grow custom size substrates and full or limited regions to confine the electron emission to the desired area. Quality emitters have been fabricated on tantalum, molybdenum, tungsten, titanium, copper, stainless steel, float glass, borosilicate glass and gallium arsenide. In addition to performing well in dedicated test chambers, a-Si photocathodes have been shown to function well in self-contained vacuum tubes. In this employment, they are subjected to a strenuous environment. Successful operation in this configuration provides additional confidence in their application to high energy linac photoinjectors and potentially as part of reliable, low cost photocathode driven RF gun systems that could become ready replacements for the diode and triode guns used on medical accelerators. Their applications in stand-alone vacuum tubes is just beginning to be explored.

Electron gun simulation with CST PARTICLE STUDIO

International Nuclear Information System (INIS)

Spachmann, Holger; Becker, Ulrich

2006-01-01

This paper introduces CST PARTICLE STUDIO TM , a specialist tool for the fast and accurate design and analysis of 3D electron guns. The new software is based on the multi-purpose electromagnetic solvers of the CST STUDIO family and incorporates their powerful modelling capabilities as well as successful algorithms of the MAFIA-TS simulators. The underlying theory of the PBA based field solvers and the used tracking technique is presented and some examples of application demonstrate the current status of the software

Electromagnetic theory of the radiative Pierce instability

International Nuclear Information System (INIS)

Klochkov, D.N.; Rukhadze, A.A.

1997-01-01

The radiative Pierce instability of a relativistic electron beam in a waveguide stabilized by an infinite strong magnetic field is considered. the increment and conditions for instability development in a wide interval of the beam currents are determined on the basis of the perturbation theory. It is shown that the instability has always the Raman character and is threshold less in current for the Pierce boundary conditions. It permits sufficiently strictly to define the instability saturation level from breaking the resonance condition and to estimate the radiation efficiency

Mechanical design and fabrication of the VHF-gun, the Berkeley normal-conducting continuous-wave high-brightness electron source

Science.gov (United States)

Wells, R. P.; Ghiorso, W.; Staples, J.; Huang, T. M.; Sannibale, F.; Kramasz, T. D.

2016-02-01

A high repetition rate, MHz-class, high-brightness electron source is a key element in future high-repetition-rate x-ray free electron laser-based light sources. The VHF-gun, a novel low frequency radio-frequency gun, is the Lawrence Berkeley National Laboratory (LBNL) response to that need. The gun design is based on a normal conducting, single cell cavity resonating at 186 MHz in the VHF band and capable of continuous wave operation while still delivering the high accelerating fields at the cathode required for the high brightness performance. The VHF-gun was fabricated and successfully commissioned in the framework of the Advanced Photo-injector EXperiment, an injector built at LBNL to demonstrate the capability of the gun to deliver the required beam quality. The basis for the selection of the VHF-gun technology, novel design features, and fabrication techniques are described.

CeB6 electron gun for the soft X-ray FEL project at SPring-8

International Nuclear Information System (INIS)

Togawa, K.; Baba, H.; Onoe, K.; Inagaki, T.; Shintake, T.; Matsumoto, H.

2004-01-01

A pulsed high-voltage electron gun with a thermionic cathode is under development for the injector system of the soft X-ray FEL project at SPring-8 (SCSS project). A CeB 6 single crystal of 3 mm diameter was chosen as a thermionic cathode because of its excellent emission properties, i.e., high resistance against contamination, uniform emission density and smooth surface. The CeB 6 cathode can produce a 3 A beam with 2 μs FWHM. A gun voltage of -500 kV was chosen as a compromise between the need for controlling emittance growth and minimizing the risks of high-voltage arcing. We have constructed a 500 kV electron gun test stand and have begun performance tests. This paper describes the basic design and the current status of the hardware R and D on the CeB 6 gun

Effect of density distribution of cathode emission on the flux character in a strong-current electron gun

International Nuclear Information System (INIS)

Matora, I.M.; Merkulov, L.A.

1975-01-01

The effect is considered of two kinds of a dependence of the emission density from the electric field voltage on the emitter surface of a strong-current electron gun (the Schottky law and the ''3/2'' law) upon the choice of a form for the meridional cross section of this emitter at the condition of electron flux laminarity. A calculation example is given for electron gun with close to laminar flow assuming the validity of the Schottky law. The results of calculation of varying the laminar flux character are given which appears when varying parameters of the gun at the voltage 500 kV and current 250 A

Investigating the effect of electron emission pattern on RF gun beam quality

Energy Technology Data Exchange (ETDEWEB)

Rajabi, A. [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Velenjak, 1983963113, Tehran (Iran, Islamic Republic of); Shokri, B., E-mail: b-shokri@sbu.ac.ir [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Velenjak, 1983963113, Tehran (Iran, Islamic Republic of); Physics Department, Shahid Beheshti University, G.C., Velenjak, 1983963113, Tehran (Iran, Islamic Republic of)

2016-05-11

Thermionic radio frequency gun is one of the most promising choices to gain a high quality electron beam, used in the infrared free electron lasers and synchrotron radiation injectors. To study the quality of the beam in a compact electron source, the emission pattern effect on the beam dynamics should be investigated. In the presented work, we developed a 3D simulation code to model the real process of thermionic emission and to investigate the effect of emission pattern, by considering geometrical constraints, on the beam dynamics. According to the results, the electron bunch emittance varies considerably with the emission pattern. Simulation results have been validated via comparison with the well-known simulation codes such as ASTRA simulation code and CST microwave studio, as well as other simulation results in the literature. It was also demonstrated that by using a continuous wave laser beam for heating the cathode, the emission pattern full width at half maximum (FWHM) of the transverse emission distribution is proportional to FWHM of the Gaussian profile for the laser beam. Additionally, by using the developed code, the effect of wall structure around the cathode on the back bombardment effect has been studied. According to the results, for a stable operation of the RF gun, one should consider the nose cone in vicinity of the cathode surface to reduce the back-bombardment effect. - Highlights: • We developed a 3D code to simulate the beam dynamics of thermionic RF gun. • Te impact of the emission pattern on the beam dynamic was investigated. • Different emission pattern results different emittance in the gun exit. • Using a nosecone around the cathode adjacent wall reduces back bombardment effect.

In Vitro Adherence of Oral Bacteria to Different Types of Tongue Piercings.

Science.gov (United States)

Borges, Lucas Pereira; Ferreira-Filho, Julio Cesar Campos; Martins, Julia Medeiros; Alves, Caroline Vieira; Santiago, Bianca Marques; Valença, Ana Maria Gondim

2016-01-01

The purpose of this work was to verify in vitro adherence of E. corrodens and S. oralis to the surface of tongue piercings made of surgical steel, titanium, Bioplast, and Teflon. For this, 160 piercings were used for the count of Colony Forming Units (CFU) and 32 piercings for analysis under scanning electron microscopy. Of these, 96 (24 of each type) were individually incubated in 5 mL of BHI broth and 50  μ L of inoculum at 37°C/24 h. The other 96 piercings formed the control group and were individually incubated in 5 mL of BHI broth at 37°C/24 h. Plates were incubated at 37°C/48 h for counting of CFU/mL and data were submitted to statistical analysis ( p value piercings, showing lower colonization ( p piercings. The four types of piercings were susceptible to colonization by E. corrodens and S. oralis , and bacterial adhesion was more significant in those made of Bioplast and Teflon. The piercings presented bacterial colonies on their surface, being higher in plastic piercings probably due to their uneven and rough surface.

The electron gun for high power high HV accelerator; Wyrzutnia elektronow do akceleratora wysokiego napiecia duzej mocy

Energy Technology Data Exchange (ETDEWEB)

Drabik, W.; Kielsznia, R.; Kapla, P.; Stras, W. [Soltan Inst. for Nuclear Studies, Otwock-Swierk (Poland)

1994-12-31

Application of electron accelerators, for purification of flue gases from SO{sub 2} and NO{sub x} in industrial mode requires electron accelerators with 200 - 300 kW power. The electron source in such accelerators has to generate the current 200 - 300 mA for long time. In this report the technical project of d.c. electron gun with parameters 250 mA, 5 kW is presented. The construction of the gun is described, it consist of cathode made of LaB{sub 6} and heater made of pyrolytic graphite. For investigation of gun characteristics the test stand was build and the result of parameters measurements are also presented. The good agreement between assumed and measured parameters has been obtained. (author). 13 refs, 20 figs.

Chaos control in an electron beam with the supercritical current in the hydrodynamic model of the Pierce diode

International Nuclear Information System (INIS)

Koronovskij, A.A.; Rempen, I.S.; Khramov, A.E.

2003-01-01

The possibility of controlling the chaos in the electron beam with the supercritical current in the hydrodynamic model of the Pierce diode through the continuous feedback; the methodology of controlling the chaotic dynamics through stabilization of the unstable equilibrium state in the distributed active medium is proposed [ru

High brightness potassium ion gun for the HIF neutralized transport experiment (NTX)

International Nuclear Information System (INIS)

Eylon, S.; Henestroza, E.; Roy, P.K.; Yu, S.S.

2003-01-01

The NTX experiment at the Heavy Ion Fusion Virtual National Laboratory is exploring the performance of neutralized final focus systems for high perveance heavy ion beams. To focus a high intensity beam to a small spot requires a high brightness beam. In the NTX experiment, a potassium ion beam of up to 400 keV and 80 mA is generated in a Pierce type diode. At the diode exit, an aperture with variable size provides the capability to vary the beam perveance and to significantly reduce the beam emittance. We shall report on the gun characterization including current density profile, phase space distributions and the control of electrons generated by the beam scraping at the aperture. Comparison with particle simulations using the EGUN code will be presented

Characteristics of a wire ion plasma source and a secondary emission electron gun

International Nuclear Information System (INIS)

Hotta, Eiki; Osawa, Teruya; Urai, Hajime; Suzuki, Mitsuaki; Yasui, Hiroyuki; Tamagawa, Tohru

1993-01-01

Electrical characteristics of a wire ion plasma source (WIPS) and a secondary emission electron gun, for which the WIPS is used as an ion source, will be reported. The WIPS is a cold-cathode gaseous discharge device, in which a radial electron trapping permits an extremely low pressure gaseous discharge with very low applied voltages. The time evolutions of temperature and density of afterglow plasma were measured with a double probe. In the case of P 0 = 25 mTorr He and the maximum discharge current of 200 A, the temperature and density of electron were about 20 eV and of the order of 10 18 m -3 , respectively, just after the distinction of discharge. The ion current density measured by a biased ion collector (BIC) on the discharge tube wall was found to reach up to 300 mA/cm 2 . A secondary emission electron gun was set on the discharge tube wall opposite to the BIC. An earthed mesh net is installed at a height of 8 mm just in front of the cathode. The maximum negative bias voltage applied to the cathode is limited to -50 kV by the local breakdown in the gun, which occurred synchronously with the WIPS discharge. The electron beam current was measured by the BIC, in which an aluminum foil with a width of 2 μm was placed on instead of the earthed mesh net. At the cathode voltage of -30 kV, the measured beam current density was 220 mA/cm 2 . The extraporation of the resulted curve indicates that if the cathode voltage is -100 kV, the current density will reach to 1 A/cm 2 . The energy spectrum of the electron beam was measured with a magnetic energy analyzer, which was set in place of the BIC. The energy spread is about 300 eV at the central energy of 40 keV. Thus, they demonstrated the possibility of a high current density secondary emission electron gun, for which a WIPS is used as an ion source

Study on corrosion products from ear piercing studs

International Nuclear Information System (INIS)

Rogero, Sizue O.; Costa, Isolda; Saiki, Mitiko

2000-01-01

In this work instrumental neutron activation analysis was applied to analyse elemental composition of commercial gold coated ear piercing substrate and metals present in their corrosion products. The cytotoxic effect was also verified in these corrosion product extracts, probably, due to the lixiviation of Ni present in high quantity in their substrates. The analysis of gold coated ear piercing surfaces by scanning electron microscopy before and after the corrosion test showed coating defects and the occurrence of corrosion process. (author)

Remoção do piercing no perioperatório Remoción del piercing en el perioperatorio Perioperative removal of body piercing

Directory of Open Access Journals (Sweden)

Solange Diccini

2008-02-01

Full Text Available A permanência do piercing no intra-operatório pode ocasionar intercorrências. Este estudo teve como objetivo determinar as intervenções de enfermagem no pré-operatório e avaliar as complicações do piercing no intra-operatório. Durante a revisão da literatura, foram incluídos 16 artigos publicados de 1994 a 2006. Nove artigos (56,2% de intervenções de enfermagem no pré-operatório, quatro (25,0% de complicações do piercing no intra-operatório e três (18,8% sobre o uso do piercing no intra-operatório, não apresentando complicações. Concluímos que a presença de piercing oral durante o intra-operatório aumenta o risco de lesões e aspiração. No corpo, a presença do piercing pode causar lesões na pele, decorrentes da mobilização do paciente e queimaduras eletrocirúrgicas. Portanto, é necessária a retirada do piercing no pré-operatório.La permanencia del piercing en el intraoperatorio puede causar algún perjuicio. Pretendemos, determinar las intervenciones de enfermería en el preoperatorio y evaluar las complicaciones del piercing en el intraoperatorio. La revisión de la literatura mostró 16 artículos publicados de 1994 a 2006. Nueve (56,2% fueron de intervenciones de enfermería en el preoperatorio, cuatro (25,0% de complicaciones del piercing en intraoperatorio, tres (18,8% no mostraron complicaciones. Concluimos, la presencia del piercing oral, durante el intraoperatório aumenta el riesgo de aspiración y daño. En el cuerpo, puede causar heridas en la piel, provocadas por la movilización del enfermo y las quemaduras, debido al uso de bisturí eléctrico durante el acto intraoperatorio. Por consiguiente, es necesario retirar el piercing en el preoperatorio.The remaining of piercing in intraoperative can cause damages. This paper had as purpose defining the nursing interventions in the intraoperative and evaluates the complications caused by piercing in the intraoperative. This literature review had 16

Should physicians have facial piercings?

Science.gov (United States)

Newman, Alison W; Wright, Seth W; Wrenn, Keith D; Bernard, Aline

2005-03-01

The objective of this study was to assess attitudes of patrons and medical school faculty about physicians with nontraditional facial piercings. We also examined whether a piercing affected the perceived competency and trustworthiness of physicians. Survey. Teaching hospital in the southeastern United States. Emergency department patrons and medical school faculty physicians. First, patrons were shown photographs of models with a nontraditional piercing and asked about the appropriateness for a physician or medical student. In the second phase, patrons blinded to the purpose of the study were shown identical photographs of physician models with or without piercings and asked about competency and trustworthiness. The third phase was an assessment of attitudes of faculty regarding piercings. Nose and lip piercings were felt to be appropriate for a physician by 24% and 22% of patrons, respectively. Perceived competency and trustworthiness of models with these types of piercings were also negatively affected. An earring in a male was felt to be appropriate by 35% of patrons, but an earring on male models did not negatively affect perceived competency or trustworthiness. Nose and eyebrow piercings were felt to be appropriate by only 7% and 5% of faculty physicians and working with a physician or student with a nose or eyebrow piercing would bother 58% and 59% of faculty, respectively. An ear piercing in a male was felt to be appropriate by 20% of faculty, and 25% stated it would bother them to work with a male physician or student with an ear piercing. Many patrons and physicians feel that some types of nontraditional piercings are inappropriate attire for physicians, and some piercings negatively affect perceived competency and trustworthiness. Health care providers should understand that attire may affect a patient's opinion about their abilities and possibly erode confidence in them as a clinician.

Design of planar electron gun for UHF range, CW power inductive output tube

International Nuclear Information System (INIS)

Kaushik, Meenu; Joshi, L.M.

2015-01-01

Inductive Output Tube (lOT) is an amplifier which is now-a-days in demand for scientific applications. For every vacuum tube, electron gun is an important part and in fact considered as the heart of the tube. Hence, designing of this component is very crucial for efficient operation of the device throughout its lifetime. This paper is all about the electromagnetic (EM) design of planar electron gun of 40 kV, 3.5 A beam voltage and beam current respectively, for a 100 kW CW power lOT operating in UHF range. The design considerations and basic equations involved in its design are included in the paper. The gun structure has been optimized for getting the desired beam characteristics. The simulation results including the beam profile along with the beam current are shown using two commercial codes namely TRAK and MAGIC code. Planar shape of electron beam reduces space charge forces in the beam itself and consequently beam energy spread for a given current. The magnetic focusing of planar beam is easier comparative to spherical beam hence, this structure has been adopted for this particular device design. (author)

Tatuajes y "piercing" Tattoos and piercing

Directory of Open Access Journals (Sweden)

L E Valle

2006-03-01

Full Text Available A pesar de estar en el siglo XXI se ha retomado el lenguaje con códigos de comunicación arcaicos. Los jóvenes forman su identidad mediante la interacción con sus pares y los tatuajes y "piercing" tienen sus propios códigos, que son interpretados por el grupo que los lleva. Actualmente los tatuajes y los "piercing" encuentran su lugar predominante en la población adolescente, donde se han reinstalado por ser "moda" y generalmente se aceptan por estar generalizados. Asimismo los observamos en poblaciones marginales: de drogadictos y carcelarias. Realizarse un tatuaje y/o "piercing" implica ciertos riesgos, entre los que podemos mencionar la transmisión de infecciones que pueden ser localizadas en las zonas del tatuaje y/o "piercing"; y/o generalizadas como las virósicas algunas de las cuales conllevan riesgos de salud como el virus del HIV, de las hepatitis A,B,C. Pueden observarse también reacciones alérgicas, de hipersensibilidad, liquenoides, granulomatosas y varias como cicatrices hipertróficas y queloides; asimismo desencadenar un primer episodio de psoriasis, lupus, etc. Dentro de las recomendaciones para informar a la población deberíamos incluir: que las regiones del cuerpo más riesgosas para la realización de los mismos (que debieran evitarse son aquellas que asientan en cabeza (incluyendo boca, nariz, cuello y órganos genitales. También es importante tener la vacunación antitetánica actualizada, considerar las condiciones de higiene del local donde se va a asistir y el tipo de material a utilizar, debiendo ser en lo posible material descartable. Los cuidados durante los primeros días post práctica son: mantener la zona limpia y seca, baños cortos, secarse sin frotado y no exponerse al sol por tres o cuatro meses. Asimismo es aconsejable ante cualquier reacción concurrir a la consulta profesional.In spite of being in the XXI century, several archaic codes of communication language have been restablished. Young

Initial results of the new high intensity electron gun at the Argonne Wakefield Accelerator

International Nuclear Information System (INIS)

Conde, M. E.; Gai, W.; Konecny, R.; Power, J. G.; Schoessow, P.; Sun, X.

2000-01-01

The authors report on the status of the new short bunch, high intensity electron gun at the Argonne Wakefield Accelerator. The 1-1/2 cell L-band photocathode RF gun is expected to produce 10--100 nC bunches with 2--5 ps rms pulse length and normalized emittance less than 100 mm mrad. The beam energy at the exit of the gun cavity will be in the range 7.5--10 MeV. A standing-wave linac structure operating at the same frequency (1.3 GHz) will increase the beam energy to about 15 MeV. This beam will be used in wakefield acceleration experiments with dielectric loaded structures. These travelling-wave dielectric loaded structures, operating at 7.8 and 15.6 GHz, will be excited by the propagation of single bunches or by trains of up to 32 electron bunches

Electromagnetic theory of the radiative Pierce instability

International Nuclear Information System (INIS)

Klochkov, D.N.; Rukhadze, A.A.

1997-01-01

A study is made of the radiative Pierce instability of a relativistic electron beam propagating in a waveguide in the presence of an infinitely strong magnetic field. The perturbation theory is used to find the growth rates and conditions of instability over a broad range of the beam current. It is shown that, under the Pierce boundary conditions, the instability is Raman in nature, and there is no current threshold for the instability. This allows the instability saturation level to be accurately determined from the condition for the violation of the Cherenkov resonance and the radiation efficiency to be estimated

Cold cathode electron guns in the LASL high power short-pulse CO2 laser program

International Nuclear Information System (INIS)

Singer, S.; Ladish, J.S.; Nutter, M.J.

1975-01-01

The Electron Beam Controlled Discharge CO 2 Laser is now firmly established as the only high power short pulse laser amplifier that has been demonstrated to have scaling capabilities to large apertures and energies much greater than 100 J. These devices require a beam of energetic electrons to control the gas discharge that produces the required population inversion. Until recently, the electron source was usually a thermionic emitter, even for rather large lasers, whose heater requirements dwarfed the pulsed energies associated with the transient operation of the laser. With the advent of reliable cold-cathode electron guns, the operation of these lasers has been greatly simplified. At LASL, there are four electron beam controlled laser systems which are in operation, under construction, or in design: the 1 kJ system, now operational; the 2.5 kJ system; the 10 kJ system; and the 100 kJ system. Only the first uses thermionic-emitter electron guns; the remainder use or will use cold cathode sources. The operation of the 200 x 35 cm 2 two sided cold cathode electron gun used in the 2.5 kJ laser system and to be used in the 10 kJ laser is described

Design and construction of a DC high-brightness laser driven electron gun

Science.gov (United States)

Zhao, K.; Geng, R. L.; Wang, L. F.; Zhang, B. C.; Yu, J.; Wang, T.; Wu, G. F.; Song, J. H.; Chen, J. E.

1996-02-01

A DC high-brightness laser driven photoemissive electron gun is being developed at Peking University, in order to produce 50-100 ps electron bunches of high quality. The gun consists of a photocathode preparation chamber and a DC acceleration cavity. Different ways of fabricating photocathodes, such as chemical vapor deposition, ion beam implantation and ion beam enhanced deposition, can be adopted. The acceleration gap is designed with the aid of simulation codes EGUN and POISSON. The laser system is a mode-locked Nd-YAG oscillator proceeded by an amplifier at 10 Hz repetition rate, which can deliver three different wavelengths (1064/532/266 nm). The combination of a superconducting cavity with the photocathode preparation chamber is also discussed in this paper.

Buneman instability and Pierce instability in a collisionless bounded plasma

International Nuclear Information System (INIS)

Iizuka, Satoru; Saeki, Koichi; Sato, Noriyoshi; Hatta, Yoshisuke

1983-01-01

A systematic experiment is performed on the Buneman instability and the Pierce instability in a bounded plasma consisting of beam electrons and stationary ions. Current fluctuations are confirmed to be induced by the Buneman instability. On the other hand, the Pierce instability gives rise to a current limitation. The phenomena are well explained by Mikhailovskii's theory taking account of ion motion in a bounded plasma. (author)

Generation of Low-Energy High-Current Electron Beams in Plasma-Anode Electron Guns

Science.gov (United States)

Ozur, G. E.; Proskurovsky, D. I.

2018-01-01

This paper is a review of studies on the generation of low-energy high-current electron beams in electron guns with a plasma anode and an explosive-emission cathode. The problems related to the initiation of explosive electron emission under plasma and the formation and transport of high-current electron beams in plasma-filled systems are discussed consecutively. Considerable attention is given to the nonstationary effects that occur in the space charge layers of plasma. Emphasis is also placed on the problem of providing a uniform energy density distribution over the beam cross section, which is of critical importance in using electron beams of this type for surface treatment of materials. Examples of facilities based on low-energy high-current electron beam sources are presented and their applications in materials science and practice are discussed.

Design and development of a ring cathode electron gun as an evaporation source

Energy Technology Data Exchange (ETDEWEB)

Poyner, G T [Craswell Scientific Ltd., Cheltenham (UK)

1976-11-01

The RG2 ring cathode gun is a simple application of electron beam heating. The gun described was developed to provide a relatively inexpensive source for evaporating a range of metals and oxides which were otherwise difficult or impossible to evaporate by conventional resistance heating. Following several stages of improvement the gun was progressively reduced in size and the 'optics', or focusing, improved so that in its existing state an area of approximately 2mm diameter is heated. It was decided to limit the accelerating voltage as far as possible to minimize the practical problems associated with its operation and also the manufacture of the power supply. As development proceeded it became apparent that the relatively low accelerating voltage chosen improved the flexibility of the gun. Two versions are manufactured, the first, equipped with a six position rotary hearth, and the second, utilising a single hearth, is intended to be used as one of a pair. The latter design was reduced in size even further in order to minimize the distance between two adjacent guns.

RF guns: a review

International Nuclear Information System (INIS)

Travier, C.

1990-06-01

Free Electron Lasers and future linear colliders require very bright electron beams. Conventional injectors made of DC guns and RF bunchers have intrinsic limitations. The recently proposed RF guns have already proven their capability to produce bright beams. The necessary effort to improve further these performances and to gain reliability is now undertaken by many laboratories. More than twenty RF gun projects both thermionic and laser-driven are reviewed. Their specific characteristics are outlined and their nominal performances are given

Body piercing with fatal consequences.

Science.gov (United States)

Ranga, N; Jeffery, A J

2011-01-25

Body modifications such as piercings, tattoos and surgery have increased in popularity in recent times and have become more socially acceptable. The common complications of piercing different parts of the human anatomy are well-documented, including sepsis, allergic reactions and, more rarely, endocarditis and ischaemia. Deaths related to piercing complications are primarily septic in origin. In this case, a man in his 50s died due to complications of his multiple umbilical piercings. The cause of death was unusually linked to body modification; the umbilical piercings had ultimately led to a mesenteric infarction. Cases such as these are forensically important due to potential manslaughter charges that could be brought against a piercing establishment. More importantly, this case highlights another extreme complication of body modification. Fashion statements are always changing and impact upon many lives. It is important to highlight to people the potentially life-threatening complications of common piercing practices.

Study on discrete space charge effects in electron beams and guns

International Nuclear Information System (INIS)

Tang Tiantong

1990-01-01

The discrete space charge effects in electron beams are studied and a statistical dynamics equation of the ensemble of beam electrons is derived. An approximated analytical solution of this equation is given. This equation has been applied to beam crossover and field-emission and thermal-emission gun problems. The computer calculation results agree on the whole with those of Monte Carlo simulation and experimental data. (orig.)

Design and Analysis of an Electron Gun/Booster and Free Electron Laser Optical Theory

Science.gov (United States)

2010-09-01

105 65. Stanford DC gun equipotentials . . . . . . . . . . . . . . . . . . . . . . 106 66. Energy plots for various electrode ratios...222 121. Graphical Cross-correlation Demonstration . . . . . . . . . . . . . . . . 223 122. 2D cross-correlation surface ...them enough energy to escape the metal’s surface . Once free of the metal, the electric field accelerates the electrons toward an anode. If the anode is

Solid-state pulse modulator using Marx generator for a medical linac electron-gun

Science.gov (United States)

Lim, Heuijin; Hyeok Jeong, Dong; Lee, Manwoo; Lee, Mujin; Yi, Jungyu; Yang, Kwangmo; Ro, Sung Chae

2016-04-01

A medical linac is used for the cancer treatment and consists of an accelerating column, waveguide components, a magnetron, an electron-gun, a pulse modulator, and an irradiation system. The pulse modulator based on hydrogen thyratron-switched pulse-forming network is commonly used in linac. As the improvement of the high power semiconductors in switching speed, voltage rating, and current rating, an insulated gate bipolar transistor has become the more popular device used for pulsed power systems. We propose a solid-state pulse modulator to generator high voltage by multi-stacked storage-switch stages based on the Marx generator. The advantage of our modulator comes from the use of two semiconductors to control charging and discharging of the storage capacitor at each stage and it allows to generate the pulse with various amplitudes, widths, and shapes. In addition, a gate driver for two semiconductors is designed to reduce the control channels and to protect the circuits. It is developed for providing the pulsed power to a medical linac electron-gun that requires 25 kV and 1 A as the first application. In order to improve the power efficiency and achieve the compactness modulator, a capacitor charging power supply, a Marx pulse generator, and an electron-gun heater isolated transformer are constructed and integrated. This technology is also being developed to extend the high power pulsed system with > 1 MW and also other applications such as a plasma immersed ion implantation and a micro pulse electrostatic precipitator which especially require variable pulse shape and high repetition rate > 1 kHz. The paper describes the design features and the construction of this solid-state pulse modulator. Also shown are the performance results into the linac electron-gun.

Solid-state pulse modulator using Marx generator for a medical linac electron-gun

International Nuclear Information System (INIS)

Lim, Heuijin; Jeong, Dong Hyeok; Lee, Manwoo; Lee, Mujin; Yi, Jungyu; Yang, Kwangmo; Ro, Sung Chae

2016-01-01

A medical linac is used for the cancer treatment and consists of an accelerating column, waveguide components, a magnetron, an electron-gun, a pulse modulator, and an irradiation system. The pulse modulator based on hydrogen thyratron-switched pulse-forming network is commonly used in linac. As the improvement of the high power semiconductors in switching speed, voltage rating, and current rating, an insulated gate bipolar transistor has become the more popular device used for pulsed power systems. We propose a solid-state pulse modulator to generator high voltage by multi-stacked storage-switch stages based on the Marx generator. The advantage of our modulator comes from the use of two semiconductors to control charging and discharging of the storage capacitor at each stage and it allows to generate the pulse with various amplitudes, widths, and shapes. In addition, a gate driver for two semiconductors is designed to reduce the control channels and to protect the circuits. It is developed for providing the pulsed power to a medical linac electron-gun that requires 25 kV and 1 A as the first application. In order to improve the power efficiency and achieve the compactness modulator, a capacitor charging power supply, a Marx pulse generator, and an electron-gun heater isolated transformer are constructed and integrated. This technology is also being developed to extend the high power pulsed system with > 1 MW and also other applications such as a plasma immersed ion implantation and a micro pulse electrostatic precipitator which especially require variable pulse shape and high repetition rate > 1 kHz. The paper describes the design features and the construction of this solid-state pulse modulator. Also shown are the performance results into the linac electron-gun

Body piercing with fatal consequences

Science.gov (United States)

Ranga, N; Jeffery, A J

2011-01-01

Body modifications such as piercings, tattoos and surgery have increased in popularity in recent times and have become more socially acceptable. The common complications of piercing different parts of the human anatomy are well-documented, including sepsis, allergic reactions and, more rarely, endocarditis and ischaemia. Deaths related to piercing complications are primarily septic in origin. In this case, a man in his 50s died due to complications of his multiple umbilical piercings. The cause of death was unusually linked to body modification; the umbilical piercings had ultimately led to a mesenteric infarction. Cases such as these are forensically important due to potential manslaughter charges that could be brought against a piercing establishment. More importantly, this case highlights another extreme complication of body modification. Fashion statements are always changing and impact upon many lives. It is important to highlight to people the potentially life-threatening complications of common piercing practices. PMID:22715261

Piercing and Tattoos

Science.gov (United States)

Piercings and tattoos are body decorations that go back to ancient times. Body piercing involves making a hole in the skin ... can be in other parts of the body. Tattoos are designs on the skin made with needles ...

Investigating the removal of body piercings.

Science.gov (United States)

Armstrong, Myrna L; Roberts, Alden E; Koch, Jerome R; Saunders, Jana C; Owen, Donna C

2007-05-01

Although body piercing procurement continues to increase, 13% to 18% of them are removed. Reasons for piercing removal in college students were examined with three groups: (a) those who kept all their piercings, (b) those who removed some, or (c) those who removed all of their body piercings. Of the sample, 41% were still pierced; 50% in their lifetime. Their major purpose for the body piercing was "helped them feel unique." Females obtained more (in high school) and then removed more, usually as upperclassmen. Males and females reported themselves as risk takers at procedure time and currently; however, only 10% cited deviancy as a reason for the body piercing(s). Only removal elements of "I just got tired of it" and "I just decided to remove it" were present, especially with the Some Removed Group. Further examination of body piercing building personal distinctiveness and self-identity to promote their need of uniqueness is suggested.

Pierce Patriarch "Prince of Quacks"

Data.gov (United States)

Department of the Interior — This article provides brief biographies for Dr. Valentine Mott Pierce and his father, Dr. Ray Vaughn Pierce. Dr. R.V. Pierce has been described as the “uberquack,”...

What Is an Oral Piercing?

Science.gov (United States)

... to your desktop! more... What Is an Oral Piercing? Article Chapters What Is an Oral Piercing? print full article print this chapter email this article Oral piercing can cause pain, swelling, infection, drooling, taste loss, ...

The Pierce-diode approximation to the single-emitter plasma diode

International Nuclear Information System (INIS)

Ender, A. Ya.; Kuhn, S.; Kuznetsov, V. I.

2006-01-01

The possibility of modeling fast processes in the collisionless single-emitter plasma diode (Knudsen diode with surface ionization, KDSI) by means of the Pierce-diode is studied. The KDSI is of practical importance in that it is an almost exact model of thermionic energy converters (TICs) in the collisionless regime and can also be used to model low-density Q-machines. At high temperatures, the Knudsen TIC comes close to the efficiency of the Carnot cycle and hence is the most promising converter of thermal to electric energy. TICs can be applied as component parts in high-temperature electronics. It is shown that normalizations must be chosen appropriately in order to compare the plasma characteristics of the two models: the KDSI and the Pierce-diode. A linear eigenmode theory of the KDSI is developed. For both nonlinear time-independent states and linear eigenmodes without electron reflection, excellent agreement is found between the analytical potential distributions for the Pierce-diode and the corresponding numerical ones for the KDSI. For the states with electron reflection, the agreement is satisfactory in a qualitative sense. A full classification of states of both diodes for the regimes with and without electron reflection is presented. The effect of the thermal spread in electron velocities on the potential distributions and the (ε,η) diagrams is analyzed. Generally speaking, the methodology developed is usefully applicable to a variety of systems in which the electrons have beam-like distributions

Genital male piercings

Directory of Open Access Journals (Sweden)

Mircea Tampa

2015-04-01

Full Text Available Body piercing has been practiced for thousands of years all over the world for beautification, religion, initiation rites or status reasons. Genital piercings also have a significant background and have been practiced for enhancing sexual pleasure, chastity, shocking or as a protest against a conservative society. As the popularity of genital piercings increased in the last years, the number of complications is also on the rise. It is therefore important for the medical professionals to have at least basic knowledge regarding this practice, as it might be required in the management of unpredictable complications.

Measures to alleviate the back bombardment effect of thermionic rf electron gun

International Nuclear Information System (INIS)

Huang, Y.; Xie, J.

1991-01-01

Thermionic rf electron gun finds application as a high brightness electron source for rf linacs. However, cathode heating from back-bombardment effect causes a ramp in the macro-pulse beam current and limit the usable pulse width. Three methods: ring cathode, magnetic deflection and laser assisted heating are studied in theory and in experiment. The results of these studies are reported

In Vitro Adherence of Oral Bacteria to Different Types of Tongue Piercings

Directory of Open Access Journals (Sweden)

Lucas Pereira Borges

2016-01-01

Full Text Available The purpose of this work was to verify in vitro adherence of E. corrodens and S. oralis to the surface of tongue piercings made of surgical steel, titanium, Bioplast, and Teflon. For this, 160 piercings were used for the count of Colony Forming Units (CFU and 32 piercings for analysis under scanning electron microscopy. Of these, 96 (24 of each type were individually incubated in 5 mL of BHI broth and 50 μL of inoculum at 37°C/24 h. The other 96 piercings formed the control group and were individually incubated in 5 mL of BHI broth at 37°C/24 h. Plates were incubated at 37°C/48 h for counting of CFU/mL and data were submitted to statistical analysis (p value <0.05. For E. corrodens, difference among types of material was observed (p<0.001 and titanium and surgical steel showed lower bacterial adherence. The adherence of S. oralis differed among piercings, showing lower colonization (p<0.007 in titanium and surgical steel piercings. The four types of piercings were susceptible to colonization by E. corrodens and S. oralis, and bacterial adhesion was more significant in those made of Bioplast and Teflon. The piercings presented bacterial colonies on their surface, being higher in plastic piercings probably due to their uneven and rough surface.

An in-situ photocathode loading system for the SLC Polarized Electron Gun

International Nuclear Information System (INIS)

Kirby, R.E.; Collet, G.J.; Skarpaas, K.

1992-12-01

An ultra-high vacuum loadlock system capable of operating at high voltage has been added to the SLC Polarized Electron Gun. The unit incorporates facilities for heat cleaning, activating and measuring the quantum efficiency of photocathodes. A tray of up to four photocathodes can be exchanged without bringing the activation unit or gun up to atmosphere. Low voltage quantum efficiencies of 20% have been obtained for bulk GaAs at 633 nm and 6% for a 0.3 micron GaAs layer at 755 nm. Results for other cathodes as well as operational characteristics are discussed

Caring for Surgical Patients With Piercings.

Science.gov (United States)

Smith, Francis Duval

2016-06-01

Body piercing, a type of body modification that is practiced in many cultures, creates an unnatural tract through tissue that is then held open by artificial means. Today, professional body piercing is often performed in piercing establishments that are subject to dissimilar forms of regulation. The most frequently reported medical complication of body piercing and similar body modifications, such as dermal implantation, is infection. Patients with piercings who undergo surgery may have additional risks for infection, electrical burns, trauma, or airway obstruction. The published research literature on piercing prevalence, complications, regulations, education, and nursing care is outdated. The purpose of this article is to educate nurses on topics related to nursing care for patients with piercings and similar body modifications, including the history, prevalence, motivations for, and perceptions of body piercings as well as possible complications, devices used, locations, healing times, regulations, patient education, and other health concerns. Copyright © 2016 AORN, Inc. Published by Elsevier Inc. All rights reserved.

The design and development of a ring cathode electron gun as an evaporation source

International Nuclear Information System (INIS)

Poyner, G.T.

1976-01-01

The RG2 ring cathode gun is a simple application of electron beam heating. The gun described was developed to provide a relatively inexpensive source for evaporating a range of metals and oxides which were otherwise difficult or impossible to evaporate by conventional resistance heating. Following several stages of improvement the gun was progressively reduced in size and the 'optics', or focusing, improved so that in its existing state an area of approximately 2mm diameter is heated. It was decided to limit the accelerating voltage as far as possible to minimize the practical problems associated with its operation and also the manufacture of the power supply. As development proceeded it became apparent that the relatively low accelerating voltage chosen improved the flexibility of the gun. Two versions are manufactured, the first, equipped with a six position rotary hearth, and the second, utilising a single hearth, is intended to be used as one of a pair. The latter design was reduced in size even further in order to minimize the distance between two adjacent guns. (author)

Tattoos, piercings, and alcohol consumption.

Science.gov (United States)

Guéguen, Nicolas

2012-07-01

Previous studies have found a link between body tattoos or piercings and risky behavior. However, these studies only examined survey data but not real behavior. Young men (mean = 20.6 years) and women (mean = 20.2 years) leaving a bar were asked whether they wore tattoos and piercings or not and were requested to breathe into a breathalyzer in order to evaluate their alcohol consumption. It was found that participants with piercings and/or tattoos as well as combined piercings and tattoos revealed higher levels of alcohol consumption. Piercings and tattoos could serve as signs of alcohol consumption for educators, parents, and physicians. Copyright © 2012 by the Research Society on Alcoholism.

Thermionic source design

International Nuclear Information System (INIS)

True, R.

1988-01-01

This paper describes codes and methods used to design high quality diode and gridded Pierce guns. Such guns are used in travelling wave tubes, klystrons, linear accelerators, free-electron lasers, and other E-beam devices. PC code TMLBMC is discussed. Either this code (or PRCGUN) can be used to obtain a preliminary gun design. Two methods useful in determining the electrode contours external to the beam (focus electrode and anode with hole) are presented. These are based on matching the fields along the beam edge and in the center of the Pierce gun. An analytic method, and a numerical method based on the solution of Laplace's equation (in combination with data from TMLBMC), are presented

Algunas consideraciones acerca de los piercings orales Some considerations about oral piercings

OpenAIRE

I De Urbiola Alís; H Viñals Iglesias

2005-01-01

Desde la antigüedad se han venido realizando piercings intraorales con motivaciones muy diversas a lo largo de la historia. Actualmente es una moda que se ha generalizado en el mundo occidental. En este artículo se explican los distintos tipos de piercings intra y periorales, sus posibles localizaciones y las complicaciones derivadas de su uso. También se dan unas recomendaciones y unas pautas de tratamiento para los profesionales que deban atender a los pacientes portadores de piercings.Intr...

Simulation of cylindrical Pierce diodes with radial flow

International Nuclear Information System (INIS)

Alves, M.V.; Gnavi, G.; Gratton, F.T.; Buenos Aires Univ.

1996-01-01

In this paper we study the electron instability and the non linear behaviour of cylindrical Pierce's diodes by particle simulation. We ignore here the ion contribution (ions are fixed at a 1/r density and given a very large mass) to give perspicuity to the electron dynamics, and to facilitate comparison with existing theory. (author). 8 refs., 10 figs

The design of electron and ion guns, beams, and collectors

Energy Technology Data Exchange (ETDEWEB)

Becker, Reinard [Institut fuer Angewandte Physik der Universitaet Frankfurt/M, Fach 180, D-60054 (Germany); Herrmannsfeldt, William B [Stanford Linear Accclerator Center, Stanford University, CA (United States)

2004-01-01

The well known 'SLAC Electron Trajectory Program' (EGUN) has been ported to PCs and has been developed into a family of programs for the design and the optimization of particle optics devices including electron and ion guns, beam transport sections and collectors. We will discuss the application of these tools for the design and the optimization of the essential parts of EBIS/T devices. The discussion will include conditions in which restrictions in the reliability of simulations may occur due to the mathematical modeling and how to overcome them.

The design of electron and ion guns, beams, and collectors

Science.gov (United States)

Becker, Reinard; Herrmannsfeldt, William B.

2004-01-01

The well known `SLAC Electron Trajectory Program' (EGUN) has been ported to PCs and has been developed into a family of programs for the design and the optimization of particle optics devices including electron and ion guns, beam transport sections and collectors. We will discuss the application of these tools for the design and the optimization of the essential parts of EBIS/T devices. The discussion will include conditions in which restrictions in the reliability of simulations may occur due to the mathematical modeling and how to overcome them.

Ion Back-Bombardment of GaAs Photocathodes Inside DC High Voltage Electron Guns

CERN Document Server

Grames, Joseph M; Brittian, Joshua; Charles, Daniel; Clark, Jim; Hansknecht, John; Lynn Stutzman, Marcy; Poelker, Matthew; Surles-Law, Kenneth E

2005-01-01

The primary limitation for sustained high quantum efficiency operation of GaAs photocathodes inside DC high voltage electron guns is ion back-bombardment of the photocathode. This process results from ionization of residual gas within the cathode/anode gap by the extracted electron beam, which is subsequently accelerated backwards to the photocathode. The damage mechanism is believed to be either destruction of the negative electron affinity condition at the surface of the photocathode or damage to the crystal structure by implantation of the bombarding ions. This work characterizes ion formation within the anode/cathode gap for gas species typical of UHV vacuum chambers (i.e., hydrogen, carbon monoxide and methane). Calculations and simulations are performed to determine the ion trajectories and stopping distance within the photocathode material. The results of the simulations are compared with test results obtained using a 100 keV DC high voltage GaAs photoemission gun and beamline at currents up to 10 mA D...

Tattoo, piercing, and adolescent tobacco consumption.

Science.gov (United States)

Guéguen, Nicolas

2013-01-01

Abstract The objective of the study was to evaluate the link between tattoos and/or piercings and young people's tobacco consumption. A total of 2587 students (1168 females and 1419 males) were asked about tattoos, piercings, and tobacco consumption. Young men and young girls who had tattoos and/or wore piercings were more likely to report smoking behavior, earlier smoking behavior, and higher cigarette consumption per day. It was also found that both with men and women, the combined effects of piercings and tattoos were associated with an increase in smoking behavior. Piercings and/or tattoos as well as combined piercings and tattoos appeared as markers of tobacco consumption. Such marks could serve as signs for educators, parents, and physicians.

Dark current studies on a normal-conducting high-brightness very-high-frequency electron gun operating in continuous wave mode

Directory of Open Access Journals (Sweden)

R. Huang

2015-01-01

Full Text Available We report on measurements and analysis of a field-emitted electron current in the very-high-frequency (VHF gun, a room temperature rf gun operating at high field and continuous wave (CW mode at the Lawrence Berkeley National Laboratory (LBNL. The VHF gun is the core of the Advanced Photo-injector Experiment (APEX at LBNL, geared toward the development of an injector for driving the next generation of high average power x-ray free electron lasers. High accelerating fields at the cathode are necessary for the high-brightness performance of an electron gun. When coupled with CW operation, such fields can generate a significant amount of field-emitted electrons that can be transported downstream the accelerator forming the so-called “dark current.” Elevated levels of a dark current can cause radiation damage, increase the heat load in the downstream cryogenic systems, and ultimately limit the overall performance and reliability of the facility. We performed systematic measurements that allowed us to characterize the field emission from the VHF gun, determine the location of the main emitters, and define an effective strategy to reduce and control the level of dark current at APEX. Furthermore, the energy spectra of isolated sources have been measured. A simple model for energy data analysis was developed that allows one to extract information on the emitter from a single energy distribution measurement.

Tattoos and piercings: bodily expressions of uniqueness?

Science.gov (United States)

Tiggemann, Marika; Hopkins, Louise A

2011-06-01

The study aimed to investigate the motivations underlying the body modification practices of tattooing and piercing. There were 80 participants recruited from an Australian music store, who provided descriptions of their tattoos and piercings and completed measures of need for uniqueness, appearance investment and distinctive appearance investment. It was found that tattooed individuals scored significantly higher on need for uniqueness than non-tattooed individuals. Further, individuals with conventional ear piercings scored significantly lower on need for uniqueness than individuals with no piercings or with facial and body piercings. Neither appearance investment nor distinctive appearance investment differed significantly among tattoo or piercing status groups. Strength of identification with music was significantly correlated with number of tattoos, but not number of piercings. It was concluded that tattooing, but not body piercing, represents a bodily expression of uniqueness. Copyright © 2011 Elsevier Ltd. All rights reserved.

Awareness of complications and maintenance mode of oral piercing in a group of adolescents and young Italian adults with intraoral piercing

Science.gov (United States)

Fusco, Francesca; Corridore, Denise; Ottolenghi, Livia

2015-01-01

Background The aim of the study was to focus the awareness of complications of oral piercing among a group of adolescents and young Italian adults with intraoral piercings. Material and Methods A total of 225 teenagers were asked to complete a questionnaire on the awareness of complications of oral piercing. An additional questionnaire was administered in case of oral piercing worn, based on site piercing, knowledge about piercer license, oral and systemic risks due to oral piercing, disinfection and sterilization of the material pierced, information by the piercer about piercing hygiene maintenance and post-piercing dentist check-up. After questionnaire all partecipants received a brochure with some information about risks and maintenance mode of piercing. Results Data revealed that more than 50% of teens surveyed was found to wear a piercing. Only 25.3% was aware of the risk of HCV cross-infection and only 17.3% reported of knowledge about risk of endocarditis. Only 17% checked the piercer license and only 18% sterilization and disinfection of the materials used. 53.7% did not received explanations about the risks associated with piercing. With regard to the maintenance mode of the piercing, it has been suggested to brush the piercing bar in 17% of cases. The post piercing specialist visits have been suggested only in 7% of cases. Conclusions The general lack of awareness of complications and maintenance mode related to oral piercing needs to be addressed by some education programs performed at school and by dentists. Key words: Oral piercing, oral health, oral complications. PMID:25858082

Development of control system for the electron gun modulator

International Nuclear Information System (INIS)

Hasegawa, T.; Nagasawa, S.; Kobayashi, T.; Hanaki, H.

2004-01-01

We have been developing a compact and inexpensive electron gun modulator for the SPring-8 Linac. The modulator was redesigned and manufactured to achieve good maintainability and high controllability. A control system of the modulator and a high voltage station is composed mainly of PLCs as a controller and touch panels for human interface. This simplified construction will result in enhancement of its reliability. The rich graphical user interface on the touch panels greatly extends the function of the control system. (author)

Therminoic gun control system for the CEBAF injector

International Nuclear Information System (INIS)

Pico, R.; Diamond, B.; Fugitt, J.; Bork, R.

1989-01-01

The injector for the CEBAF accelerator must produce a high-quality electron beam to meet the overall accelerator specifications. A Hermosa electron gun with a 2 mm-diameter cathode and a control aperture has been chosen as the electron source. This must be controlled over a wide range of operating conditions to meet the beam specifications and to provide flexibility for accelerator commissioning. The gun is controlled using Computer Automated Measurement and Control (CAMAC IEEE-583) technology. The system employs the CAMAC-based control architecture developed at CEBAF. The control system has been tested, and early operating data on the electron gun and the injector beam transport system has been obtained. This system also allows gun parameters to be stored at the operator location, without paralyzing operation. This paper describes the use of this computer system in the control of the CEBAF electron gun. 2 refs., 6 figs., 1 tab

Testing a GaAs cathode in SRF gun

International Nuclear Information System (INIS)

Wang, E.; Kewisch, J.; Ben-Zvi, I.; Burrill, A.; Rao, T.; Wu, Q.; Holmes, D.

2011-01-01

RF electron guns with a strained superlattice GaAs cathode are expected to generate polarized electron beams of higher brightness and lower emittance than do DC guns, due to their higher field gradient at the cathode's surface and lower cathode temperature. We plan to install a bulk GaAs:Cs in a SRF gun to evaluate the performance of both the gun and the cathode in this environment. The status of this project is: In our 1.3 GHz 1/2 cell SRF gun, the vacuum can be maintained at nearly 10 -12 Torr because of cryo-pumping at 2K. With conventional activation of bulk GaAs, we obtained a QE of 10% at 532 nm, with lifetime of more than 3 days in the preparation chamber and have shown that it can survive in transport from the preparation chamber to the gun. The beam line has been assembled and we are exploring the best conditions for baking the cathode under vacuum. We report here the progress of our test of the GaAs cathode in the SRF gun. Future particle accelerators, such as eRHIC and the ILC require high-brightness, high-current polarized electrons. Strained superlattice GaAs:Cs has been shown to be an efficient cathode for producing polarized electrons. Activation of GaAs with Cs,O(F) lowers the electron affinity and makes it energetically possible for all the electrons, excited into the conduction band that drift or diffuse to the emission surface, to escape into the vacuum. Presently, all operating polarized electron sources, such as the CEBAF, are DC guns. In these devices, the excellent ultra-high vacuum extends the lifetime of the cathode. However, the low field gradient on the photocathode's emission surface of the DC guns limits the beam quality. The higher accelerating gradients, possible in the RF guns, generate a far better beam. Until recently, most RF guns operated at room temperature, limiting the vacuum to ∼10 -9 Torr. This destroys the GaAs's NEA surface. The SRF guns combine the excellent vacuum conditions of DC guns and the high accelerating

[Genital piercings: epidemiology, sociocultural aspects, sexuality and complications].

Science.gov (United States)

Kluger, Nicolas

2012-01-01

Body piercing has gained tremendous popularity since the mid nineties. Genital piercings constitute a peculiar variant of piercing due to its sensitive localization. Health care providers are often very little informed about those piercings. Besides, negative stereotypes are often attributed to the bearers of such piercings. This review focuses not only on the medical aspects of genital piercings but also on the social, cultural and psychological background that surround those piercings. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

[Piercings--what the physician needs to know?].

Science.gov (United States)

Kluger, Nicolas; Koljonen, Virve

2012-01-01

Body piercing (BP) is defined as penetration of jewellery through the skin. Along with tattooing BPs are the most common body modifications. Complications related to piercing are numerous. They can be acute or chronic, infectious or non infectious and local or systemic complications. Acute infections constitute the most important complications and occur independently of the piercing site. Special attention should be brought on oral piercings, as they are frequent and responsible for numerous complications. A non-judgmental approach is recommended, when a pierced patient seeks medical help for a piercing complication or any other health issue.

Do long-term tongue piercings affect speech quality?

Science.gov (United States)

Heinen, Esther; Birkholz, Peter; Willmes, Klaus; Neuschaefer-Rube, Christiane

2017-10-01

To explore possible effects of tongue piercing on perceived speech quality. Using a quasi-experimental design, we analyzed the effect of tongue piercing on speech in a perception experiment. Samples of spontaneous speech and read speech were recorded from 20 long-term pierced and 20 non-pierced individuals (10 males, 10 females each). The individuals having a tongue piercing were recorded with attached and removed piercing. The audio samples were blindly rated by 26 female and 20 male laypersons and by 5 female speech-language pathologists with regard to perceived speech quality along 5 dimensions: speech clarity, speech rate, prosody, rhythm and fluency. We found no statistically significant differences for any of the speech quality dimensions between the pierced and non-pierced individuals, neither for the read nor for the spontaneous speech. In addition, neither length nor position of piercing had a significant effect on speech quality. The removal of tongue piercings had no effects on speech performance either. Rating differences between laypersons and speech-language pathologists were not dependent on the presence of a tongue piercing. People are able to perfectly adapt their articulation to long-term tongue piercings such that their speech quality is not perceptually affected.

Design of a high repetition rate S-band photocathode gun

International Nuclear Information System (INIS)

Han Janghui; Cox, Matthew; Huang, Houcheng; Pande, Shivaji

2011-01-01

Photocathode RF guns have been developed in many laboratories for generating high quality electron beams for free-electron lasers based on linear accelerators. Such guns can generate electron beams with an exceptionally high peak current as well as a small transverse emittance. Their applications have been recently expanded for ultrafast electron diffraction, coherent terahertz radiation, and X-ray or γ-ray radiation by Compton scattering. In this paper, we design an S-band normal-conducting gun with capabilities of high quality beam generation and high repetition rate operation. The RF design and thermal analysis of the gun cavity and coupler are introduced. Optimal position of the gun focusing solenoid for low emittance beam generation is found by performing particle tracking simulations. Then, the gun system is designed to be able to afford the optimal solenoid position. The cooling-water channel surrounding the gun cavity and coupler is designed and analyzed numerically. The pressure in the gun is simulated with a vacuum model containing the detailed inner structure of the gun. An injector for a free-electron laser application is designed by using this gun and the beam dynamics simulation is shown. A cold test with a prototype gun for confirmation of the RF design is reported. - Highlights: → We design an S-band gun for low emittance beam generation and high repetition rate operation. → The RF design and thermal analysis of the gun cavity and coupler are studied. → An FEL injector is designed by using this gun and the beam dynamics simulation is shown. → A cold test with a prototype gun for confirmation of the RF design is reported.

Advanced laser technologies for high-brightness photocathode electron gun

International Nuclear Information System (INIS)

Tomizawa, Hiromitsu

2012-01-01

A laser-excited photocathode RF gun is one of the most reliable high-brightness electron beam sources for XFELs. Several 3D laser shaping methods have been developed as ideal photocathode illumination sources at SPring-8 since 2001. To suppress the emittance growth caused by nonlinear space-charge forces, the 3D cylindrical UV-pulse was optimized spatially as a flattop and temporally as squarely stacked chirped pulses. This shaping system is a serial combination of a deformable mirror that adaptively shapes the spatial profile with a genetic algorithm and a UV-pulse stacker that consists of four birefringent α-BBO crystal rods for temporal shaping. Using this 3D-shaped pulse, a normalized emittance of 1.4 πmm mrad was obtained in 2006. Utilizing laser's Z-polarization, Schottky-effect-gated photocathode gun was proposed in 2006. The cathode work functions are reduced by a laser-induced Schottky effect. As a result of focusing a radially polarized laser pulse with a hollow lens in vacuum, the Z-field (Z-polarization) is generated at the cathode. (author)

Advanced Laser Technologies for High-brightness Photocathode Electron Gun

Science.gov (United States)

Tomizawa, Hiromitsu

A laser-excited photocathode RF gun is one of the most reliable high-brightness electron beam sources for XFELs. Several 3D laser shaping methods have been developed as ideal photocathode illumination sources at SPring-8 since 2001. To suppress the emittance growth caused by nonlinear space-charge forces, the 3D cylindrical UV-pulse was optimized spatially as a flattop and temporally as squarely stacked chirped pulses. This shaping system is a serial combination of a deformable mirror that adaptively shapes the spatial profile with a genetic algorithm and a UV-pulse stacker that consists of four birefringent α-BBO crystal rods for temporal shaping. Using this 3D-shaped pulse, a normalized emittance of 1.4 π mm mrad was obtained in 2006. Utilizing laser's Z-polarization, Schottky-effect-gated photocathode gun was proposed in 2006. The cathode work functions are reduced by a laser-induced Schottky effect. As a result of focusing a radially polarized laser pulse with a hollow lens in vacuum, the Z-field (Z-polarization) is generated at the cathode.

CID thermionic gun system

International Nuclear Information System (INIS)

Koontz, R.F.

1981-10-01

A new high-current thermionic gun has been installed on the CID injector at SLAC and brought into operation. The gun and pulser system generate three nanosecond pulses of about six amps peak which, when bunched in the subharmonic buncher system, produce in excess of 10 11 electrons in a single S-band accelerated bunch. Preliminary operation of the gun is described, and details of the avalanche cathode drive pulser are presented

CID thermionic gun system

International Nuclear Information System (INIS)

Koontz, R.F.

1982-01-01

A new high-current thermionic gun has been installed on the CID injector at SLAC and brought into operation. The gun and pulser system generate three nanosecond pulses of about six amps peak which, when bunched in the subharmonic buncher system, produce in excess of 10 11 electrons in a single S-band accelerated bunch. Preliminary operation of the gun is described, and details of the avalanche cathode drive pulser are presented

Design of a pulsed angular selective electron gun for the KATRIN main spectrometer

Energy Technology Data Exchange (ETDEWEB)

Winzen, Daniel; Hannen, Volker; Ortjohann, Hans-Werner; Zacher, Michael; Weinheimer, Christian [Institut fuer Kernphysik, Westfaelische Wilhelms-Universitaet, Muenster (Germany); Collaboration: KATRIN-Collaboration

2012-07-01

The KATRIN (KArlsruhe TRItium Neutrino mass) experiment will study the tritium {beta}-spectrum near the endpoint of 18.6 keV, aiming to measure the mass of the electron antineutrino. Using an electrostatic retarding spectrometer (MAC-E-Filter), the projected sensitivity for m{sub ve} is 200 meV/c{sup 2} at 90% C.L. In order to map out the electric and magnetic fields in the main spectrometer, an angular selective electron gun is currently being developed. The e-gun uses an UV-Laser to produce electrons via the photo-electric effect from a copper substrate which are then accelerated electrostatically. It features a small energy spread of approx. 0.1 eV, a sharp emission angle and will be able to cover the whole magnetic flux tube of KATRIN. Using a pulsed laser it is also possible to investigate the time of flight (TOF) of electrons through the spectrometer, offering enhanced sensitivity to spectrometer properties far away from the analysing plane. By comparing information from transmission function measurements and TOF data with Monte Carlo simulations of the setup, one will be able to achieve a detailed understanding of the spectrometer properties.

With Nipple Piercing

Directory of Open Access Journals (Sweden)

Mark D. Pearlman

1995-01-01

Full Text Available Background: Breast abscesses are typically seen in the setting of complicated mastitis in lactating women. Abscesses resulting from foreign bodies are not commonly seen in the breast. Over the past few decades, body piercing has become increasingly common, yet the infectious morbidity resulting from it is not well recognized. A breast abscess associated with nipple piercing is described in this report.

Simulation and analysis of secondary emission microwave electron gun

International Nuclear Information System (INIS)

He Wencan; Pei Yuanji; Jin Kai; Wu Congfeng

2001-01-01

The development of high-current, short-duration pulses of electrons has been a challenging problem for many year. Micro-pulse-gun (MPG) is a novel concept that employs the resonant amplification of an electron current by secondary electron emission in a RE cavity. Using the computation code URMEL-T, several kinds of RF cavities under the frequency of 2856 MHz were calculated and optimized, the magnetic and electric field distribution in them were got. Through particle-in-cell (PIC) simulation, the self-bunching process in a MPG was proved, the relationship between the cavity length and selected phase and the relationship between the peak electric field and selected phase were got. With cathode material of high secondary emission coefficient, the MPG can produce high current densities (1132-5303 A/cm 2 ) and short pulses (3.15-10 ps)

Stability and performance studies of the PITZ photoelectron gun

Energy Technology Data Exchange (ETDEWEB)

Isaev, Igor

2018-02-15

The invention of free electron lasers (FELs) opened new opportunities for the investigation of natural phenomena. However, the operation of a FEL requires high energy, high peak current electron beams with very small transverse emittance which causes extreme requirements for the corresponding electron sources. Besides the high beam quality, the electron sources must have very high operational stability and reliability. One of the electron source types which satisfy FEL requirements is a photoelectron gun. Photoelectron guns combine photoemissive electron generation and direct acceleration in a Radio Frequency (RF) cavity. The Photo Injector Test facility at DESY, Zeuthen site (PITZ), was established as a test stand of the electron source for FELs like FLASH and the European XFEL in Hamburg. The studies of the beam emittance at PITZ showed that the gun is able to produce electron beams with emittance even smaller than it is required by XFEL specifications. But the experiments on the emittance revealed discrepancies between expected gun behavior and observation, such as the difference in optimal parameters for the smallest emittance value, asymmetry of the transverse beam profile and the phase spaces. The work performed at PITZ includes preparation of several RF guns for their subsequent operation at FLASH and the European XFEL. RF conditioning of a gun cavity is one of the major steps of the preparation of a high brightness electron source required for modern FELs. A thorough procedure is applied to increase the peak and average RF power in the gun cavity, including an increase of the repetition rate and RF pulse length combined with a gun solenoid current sweep. The main goals of this thesis are: (1) an attempt of deep understanding of physical processes taking place during operation of a photoelectron gun (conditioning process, parameters adjustments); (2) definition of operational problems sources and explanation of the experimentally obtained results in the gun

Stability and performance studies of the PITZ photoelectron gun

International Nuclear Information System (INIS)

Isaev, Igor

2018-02-01

The invention of free electron lasers (FELs) opened new opportunities for the investigation of natural phenomena. However, the operation of a FEL requires high energy, high peak current electron beams with very small transverse emittance which causes extreme requirements for the corresponding electron sources. Besides the high beam quality, the electron sources must have very high operational stability and reliability. One of the electron source types which satisfy FEL requirements is a photoelectron gun. Photoelectron guns combine photoemissive electron generation and direct acceleration in a Radio Frequency (RF) cavity. The Photo Injector Test facility at DESY, Zeuthen site (PITZ), was established as a test stand of the electron source for FELs like FLASH and the European XFEL in Hamburg. The studies of the beam emittance at PITZ showed that the gun is able to produce electron beams with emittance even smaller than it is required by XFEL specifications. But the experiments on the emittance revealed discrepancies between expected gun behavior and observation, such as the difference in optimal parameters for the smallest emittance value, asymmetry of the transverse beam profile and the phase spaces. The work performed at PITZ includes preparation of several RF guns for their subsequent operation at FLASH and the European XFEL. RF conditioning of a gun cavity is one of the major steps of the preparation of a high brightness electron source required for modern FELs. A thorough procedure is applied to increase the peak and average RF power in the gun cavity, including an increase of the repetition rate and RF pulse length combined with a gun solenoid current sweep. The main goals of this thesis are: (1) an attempt of deep understanding of physical processes taking place during operation of a photoelectron gun (conditioning process, parameters adjustments); (2) definition of operational problems sources and explanation of the experimentally obtained results in the gun

Lasers for RF guns: Proceedings

International Nuclear Information System (INIS)

Srinivasan-Rao, T.

1994-01-01

In the past decade, laser driven RF guns have matured from a device under development to a proven source for high brightness and low emittance electron beams. The reliability of the electron beam from these sources is dictated by the laser system that drives it. In addition, capabilities of the laser systems play a vital role in the design of the electron source for future machines such as the TESLA and NLC. The purpose of this workshop was to provide a forum for discussing the design criteria for the laser systems so that the reliability of the existing sources could be improved and the future machines could be serviced. The Workshop brought together experts in RF Guns, accelerators, and lasers, from both the commercial and academic community. Most of the presentations, discussions and conclusions at the workshop are included in these proceedings. The contents are divided into three sections, Section I contains the invited talks that outline the requirements of the RF Guns and the capabilities of the laser systems to meet these requirements. Section II includes most of the papers presented in the poster session. These papers describe various laser systems used with electron guns, schemes to modify the laser beam profile to optimize the electron bunch, and computer simulations of electron trajectories. Section III contains the summaries of the working groups. As the summary section indicates, with sufficient feed back systems, the electron gun could be made to operate reliably with minimum downtime, using commercial lasers currently available. The design of laser systems for future colliders depend critically on the choice of the cathode m the gun and its efficiency. Tentative designs of laser systems for the TESLA test facility and LCLS had been drawn assuming a copper cathode. Using a more efficient cathode will ease the energy requirement of the laser and simplify the design. The individual papers have been cataloged separately elsewhere

Perceptions of visible piercings: a pilot study.

Science.gov (United States)

Martino, Sara; Lester, David

2011-12-01

49 undergraduates were shown pictures of a man and a woman with piercings and with no piercings. The pierced model was judged to be less attractive and less normal than the nonpierced model. The pierced model was perceived as less intelligent, caring, generous, honest, and religious but more artistic and mysterious.

Oral and perioral piercings in Tshwane.

Science.gov (United States)

Ebrahim, R; Naidoo, S

2008-06-01

Oral and perioral piercings have recently become very popular and many patients present at dental clinics and practices with jewellery inserted into the oral and perioral tissues. It is imperative that oral health care professionals become familiar with this practice, become aware of its sequelae, and are able to provide oral health education regarding oral hygiene and care of the piercing. The present study investigated the sites of oral piercings, complications associated with piercings, plaque control procedures practised by piercees, and the attitude and behaviour of piercers towards infection control and prevention of complications after a piercing. A convenience sample was used and 126 piercees and 10 piercers completed a self-administered questionnaire. Of the 126 participants (107 females and 19 males), 88.10% had a tongue piercing, 19.84% had a lip piercing and 7.94% had both. The most common immediate post-procedure sequelae were pain (69.05%), swelling (52.38%) and difficulty eating, speaking and swallowing (70.63%). Long-term complications were reported by 17.56% of the sample, and included chipping of teeth, gingival recession, lesions on the tongue and palate, painful gums, and sensitivity of teeth. Oral health professionals need to be aware of the risk of damage to soft and hard tissue, and their role in informing patients about the potential risks, if consulted before a piercing.

Development of a new electron gun pulser by using high-speed MOS-FET's

International Nuclear Information System (INIS)

Suzuki, Ryoichi; Mikado, Tomohisa; Ohgaki, Hideaki; Chiwaki, Mitsukuni; Yamada, Kawakatsu; Sei, Norihiro; Sugiyama, Suguru; Noguchi, Tsutomu; Yamazaki, Tetsuo

1993-01-01

A new pulser for a low-emittance electron gun of the ETL linac has been developed by using high-speed MOS-FET's. The pulser can produce pulses of variable pulse width (5 ns - 4 μs) and of variable pulse height. Furthermore, the pulser can be operated with burst mode (100 ns period, more than 20 cycles) for single bunch injection to electron storage rings. (author)

State-of-the-Art Electron Guns and Injector Designs for Energy Recovery Linacs (ERL)

CERN Document Server

Todd, Alan; Ben-Zvi, Ilan; Benson, Stephen V; Blüm, Hans; Burrill, Andrew; Calaga, Rama; Cameron, Peter; Campisi, Isidoro E; Chang, Xiangyun; Christina, Vincent; Cole, Michael; Colestock, Patrick L; Daly, Edward; Douglas, David; Dylla, Fred H; Falletta, Michael; Hahn, Harald; Hernandez-Garcia, Carlos; Hogan, John; Holmes, Douglas; Janssen, Dietmar; Kayran, Dmitry; Kelley, John P; Kewisch, Jorg; Kneisel, Peter; Kurennoy, Sergey; Lewellen, John W; Litvinenko, Vladimir N; Mammosser, John; McIntyre, Gary; Neil, George R; Nguyen, Dinh C; Nicoletti, Tony; Peterson, Ed; Phillips, Larry; Preble, Joseph P; Rank, Jim; Rao, Triveni; Rathke, John; Reass, William; Rees, Daniel; Rimmer, Robert; Rode, Claus; Russell, Steven; Scaduto, Joseph; Schrage, Dale L; Schultheiss, Tom; Sekutowicz, Jacek; Siggins, Tim; Warren Funk, L; Whitlach, Timothy; Wiseman, Mark; Wong, Robert; Wood, Richard L; Wu, Kuo-Chen; Young, Lloyd M; Zaltsman, Alex; Zhao, Yongxiang

2005-01-01

A key technology issue of ERL devices for high-power free-electron laser (FEL) and 4th generation light sources is the demonstration of reliable, high-brightness, high-power injector operation. Ongoing programs that target up to 1 Ampere injector performance at emittance values consistent with the requirements of these applications are described. We consider that there are three possible approaches that could deliver the required performance. The first is a DC photocathode gun and superconducting RF (SRF) booster cryomodule. Such a 750 MHz device is being integrated and will be tested up to 100 mA at the Thomas Jefferson National Accelerator Facility beginning in 2007. The second approach is a high-current normal-conducting RF photoinjector. A 700 MHz gun will undergo thermal test in 2006 at the Los Alamos National Laboratory, which, if successful, when equipped with a suitable cathode, would be capable of 1 Ampere operation. The last option is an SRF gun. A half-cell 703 MHz SRF gun capable of delivering 1.0...

The ASDEX 100 keV neutral lithium beam diagnostic gun

International Nuclear Information System (INIS)

McCormick, K.; Kick, M.

1983-04-01

The neutral lithium beam gun intended for measurement of the poloidal magnetic field and of the density gradient in the scrape-off layer of ASDEX is described, and test results over a beam energy range of 27-100 keV are presented. In the gun, lithium ions are extracted from a solid emitter (#betta#-Eurcryptite) in a Pierce-type configuration, accelerated and focused in a two-tube immersion lens, and neutralized in a charge-exchange cell using sodium. The beam can be pulsed from less than one to several seconds, depending on experimental needs. At a distance of 165 cm from the gun the neutral beam equivalent current is typically greater than 1 mA (0.16 mA) for a beam energy of 100 keV (27 keV), the beam FWHM being about 8-9 mm. It is found that to produce a particular beam with a certain ratio must be maintained between the extraction and total beam voltages, this relationship depending in turn on the emitter-extractor separation. The principal features which distinguish the ASDEX gun from that employed on W7a are the greater compactness - all the active elements, i.e. emitter, extractor, lens, deflection plates and neutralizer, are contained with 57 cm - and the vacuum vessel, which simultaneously serves as the magnetic shielding. (orig.)

Efficient temporal shaping of electron distributions for high-brightness photoemission electron guns

Directory of Open Access Journals (Sweden)

Ivan V. Bazarov

2008-04-01

Full Text Available To achieve the lowest emittance electron bunches from photoemission electron guns, it is essential to limit the uncorrelated emittance growth due to space charge forces acting on the bunch in the vicinity of the photocathode through appropriate temporal shaping of the optical pulses illuminating the photocathode. We present measurements of the temporal profile of electron bunches from a bulk crystal GaAs photocathode illuminated with 520 nm wavelength pulses from a frequency-doubled Yb-fiber laser. A transverse deflecting rf cavity was used to make these measurements. The measured laser pulse temporal profile and the corresponding electron beam temporal profile have about 30 ps FWHM duration, with rise and fall times of a few ps. GaAs illuminated by 520 nm optical pulses is a prompt emitter within our measurement uncertainty of ∼1  ps rms. Combined with the low thermal emittance of negative electron affinity photocathodes, GaAs is a very suitable photocathode for high-brightness photoinjectors. We also report measurements of the photoemission response time for GaAsP, which show a strong dependence on the quantum efficiency of the photocathode.

Is chronic nipple piercing associated with hyperprolactinemia?

Science.gov (United States)

Sun, Grace E Ching; Pantalone, Kevin M; Gupta, Manjula; Kennedy, Laurence; Nasr, Christian; Constantiner, Marigel; Hamrahian, Amir H; Hatipoglu, Betul

2013-09-01

Literature on hyperprolactinemia in the setting of a nipple piercing is limited to individuals with concomitant breast/chest wall infection. It is unclear if chronic nipple stimulation from a piercing alone can cause sustained elevations of serum prolactin. Nipple piercing is emerging as a more mainstream societal form of body art, and the answer to this clinical question would potentially alter patient management. Our aim was to assess serum prolactin levels in subjects with nipple piercing. Inclusion criteria were as follows: men and women ≥ 18 years old with nipple piercing(s) present > 6 months. Exclusion criteria included: women who are pregnant, lactating or men and eight women were enrolled. Median (range) ages for men and women were 33 (24-42) and 27 years (23-42), respectively. All except one subject had bilateral piercings. The median interval from nipple piercing to blood draw was 4.0 (2.0-12.0) years. None of the subjects had hyperprolactinemia. Median (range) prolactin levels for men and women were 5.6 ng/mL (3.8-7.4) and 8.0 ng/mL (2.8-10.9), respectively. Our results suggest that in the absence of any concomitant infection, chronic nipple piercing is not associated with hyperprolactinemia.

Finite ion velocity effects on the stability of Pierce-like diodes

International Nuclear Information System (INIS)

Kolinsky, H.; Schamel, H.

1994-01-01

The stability of Pierce-like plasma diodes is investigated for arbitrary ion injection velocities. A recently developed integral formalism that accounts for ion dynamical effects is applied to derive a generalized dispersion relation for electrostatic perturbations. Its evaluation exhibits several new features, such as the appearance of growing oscillatory modes, which become Pierce--Buneman modes in the limit of initially resting ions, and of weakly damped oscillatory modes, which become undamped ion plasma oscillations in this limit. The stability of this bounded plasma system is shown to be controlled by the new control parameter at signga=α(1+at signgm) 1/2 , where α is the Pierce parameter and at signgm≡m ev 2 e0 /m iv 2 i0 the ratio of electron and ion kinetic energy at the emitter

Isolated grid electron gun and pulser system for long/short pulse operation

International Nuclear Information System (INIS)

Koontz, R.F.; Feathers, L.; Kilbourne, C.; Leger, G.; McKinney, T.

1984-04-01

The new NPI gun at SLAC serves the dual functions of producing long pulse (up to 5 μsec, 180 pps) electron bursts for nuclear physics experiments, and also short (1 nsec) pulses for filling Stanford Synchrotron Radiation Laboratory (SSRL). This is accomplished by means of a newly designed, isolated grid gun, cathode pulsed with a solid state long pulse pulser, and grid pulsed with a fast recharging avalanche type short pulse (1 nsec) grid pulser. The grid pulser is bipolar so that a fast blackout notch can be placed in the long cathode pulse. This fast notch can be seen by Stanford Linear Collider (SLC) instrumentation and allows the long pulse beam to be computer controlled by SLC intensity and beam position monitors

Modification of the pierce instability of the electron flow in a diode with an external electromagnetic action

International Nuclear Information System (INIS)

Melezhik, O.G.; Pashchenko, A.V.; Romanov, S.S.; Shapoval, I.M.

2014-01-01

The stability of electron flow passage through the diode with a neutralized space charge has been investigated on the basis of the first-order approximation for hydrodynamic and Maxwell equations. Classification of solutions to the equations was developed in accordance with the magnitude and nature (potential or eddy) of the electric field arising at the diode cathode. The stability regions for these states have been found. It is shown that the presence of external electromagnetic action makes the stability region narrower than that predicted by Pierce.

Genital piercings: what is known and what people with genital piercings tell us.

Science.gov (United States)

Armstrong, Myrna L; Caliendo, Carol; Roberts, Alden E

2006-06-01

General and subjective information about those who chose to obtain genital piercings was presented. Particularly, the assumptions made from the literature are refuted by objective and subjective data collected from intimately pierced individuals themselves. Professional nurses must not base practice decisions on assumptions but on the "best evidence with clinical experience, research, (as well as) associated patient values" (Sackett, Strauss, Richardson, Rosenberg, & Haynes, 2001, p. 10). Thus, providing clinically competent care is driven by the latest knowledge and evidence from research and patient sources. Data found here provide further empirical evidence that may help to improve client outcomes by advancing evidence-based nursing practice in relation to people with genital piercings.

In Vitro Study on the Adhesion and Colonization of Candida Albicans on Metal and Acrylic Piercings

Directory of Open Access Journals (Sweden)

Stamenov N.

2016-03-01

Full Text Available Oral/perioral piercing may provide an ideal environment for adhesion and colonization of microorganisms. The aim of this study is to perform an “in vitro” research on the capabilities of adhesion of Candida albicans on oral piercings made of plastic and metal. Acrylic and metal piercings were incubated with Candida albicans and then were observed using scanning electron microscopy under different magnifications. A lot of irregularities and roughness were observed on the surface of the plastic piercing unlike the surface of the metal one, which is not so rough. Nevertheless, the number of Candida albicans colonies was considerably larger on the scanned metal surface in comparison to the plastic surface. In vitro the metal surface of the piercing creates better environment for the adhesion and colonization of microorganisms than the acrylic. This could be attributed to the electrostatic forces that most likely attract Candida albicans to the metal piercing in the early stages of biofilm formation.

A high-compression electron gun for C6+ production: concept, simulations and mechanical design

Science.gov (United States)

Mertzig, Robert; Breitenfeldt, M.; Mathot, S.; Pitters, J.; Shornikov, A.; Wenander, F.

2017-07-01

In this paper we report on simulations and the mechanical design of a high-compression electron gun for an Electron Beam Ion Source (EBIS) dedicated for production of high intensity and high repetition rate pulses of bare carbon ions for injection into linac-based hadron therapy facilities. The gun is presently under construction at CERN to be retrofitted into the TwinEBIS test bench for experimental studies. We describe the design constraints, show results of numeric simulations and report on the mechanical design featuring several novel ideas. The reported design makes use of combined-function units with reduced number of mechanical joints that were carefully controlled and tuned during the manufacturing phase. The simulations addressed a wide range of topics including the influence of thermal effects, focusing optics, symmetry-breaking misalignments and injection into a full 5 T field.

Long pulse, plasma cathode E-gun

International Nuclear Information System (INIS)

Goebel, D.M.; Schumacher, R.W.; Watkins, R.M.

1993-01-01

A unique, long-pulse E-gun has been developed for high-power tube applications. The Hollow-Cathode-Plasma (HCP) E-gun overcomes the limitations of conventional thermionic-cathode guns that have limited current density (typically ≤ 10 A/cm 2 ) or field-emission guns that offer high current density but suffer from short pulsewidth capability (typically 50 A/cm 2 ), long-pulse operation without gap closure, and also requires no cathode-heater power. The gun employs a low-pressure glow discharge inside a hollow cathode (HC) structure to provide a stable, uniform plasma surface from which a high current-density electron beam can be extracted. The plasma density is controlled by a low-voltage HC discharge pulser to produce the desired electron current density at the first grid of a multi-grid accelerator system. A dc high-voltage electron-beam supply accelerates the electrons across the gap, while the HC pulser modulates the beam current to generate arbitrary pulse waveforms. The electron accelerator utilizes a multi-aperture array that produces a large area, high perveance (>35 μpervs) beam consisting initially of many individual beamlets. The E-beam is normally operated without an applied magnetic field in the ion-focused regime, where the plasma produced by beam ionization of a background gas space-charge neutralizes the beam, and the Bennett self-pinch compresses the beamlets and increases the current density. The self-pinched beam has been observed to propagate over a meter without beam breakup or instabilities. The HCP E-gun has been operated at voltages up to 150 kV, currents up to 750 A, and pulse lengths of up to 120 μsec

Genital piercings: diagnostic and therapeutic implications for urologists.

Science.gov (United States)

Nelius, Thomas; Armstrong, Myrna L; Rinard, Katherine; Young, Cathy; Hogan, LaMicha; Angel, Elayne

2011-11-01

To provide quantitative and qualitative data that will assist evidence-based decision making for men and women with genital piercings (GP) when they present to urologists in ambulatory clinics or office settings. Currently many persons with GP seek nonmedical advice. A comprehensive 35-year (1975-2010) longitudinal electronic literature search (MEDLINE, EMBASE, CINAHL, OVID) was conducted for all relevant articles discussing GP. Authors of general body art literature tended to project many GP complications with potential statements of concern, drawing in overall piercings problems; then the information was further replicated. Few studies regarding GP clinical implications were located and more GP assumptions were noted. Only 17 cases, over 17 years, describe specific complications in the peer-reviewed literature, mainly from international sources (75%), and mostly with "Prince Albert" piercings (65%). Three cross-sectional studies provided further self-reported data. Persons with GP still remain a hidden variable so no baseline figures assess the overall GP picture, but this review did gather more evidence about GP wearers and should stimulate further research, rather than collectively projecting general body piercing information onto those with GP. With an increase in GP, urologists need to know the specific differences, medical implications, significant short- and long-term health risks, and patients concerns to treat and counsel patients in a culturally sensitive manner. Targeted educational strategies should be developed. Considering the amount of body modification, including GP, better legislation for public safety is overdue. Copyright © 2011 Elsevier Inc. All rights reserved.

A study of an electron gun controlled with a meshless grid for a linear accelerator

International Nuclear Information System (INIS)

Homma, Akira; Nakata, Katsuhide; Sawamura, Teruko; Narita, Masakuni

1996-01-01

An electron gun for a linear accelerator with a control grid of meshless electrode (meshless grid) is expected to overcome some disadvantages of beam quality using an ordinary mesh grid. A gun of this type was designed and its characteristics were numerically analyzed. The simulation program code Egn2 with a boundary setting routine POLYGON was used. The result indicated that the grid can control the beam launched from the cathode to the anode electrode. It also indicated the Ip-Vp and Ip-Vp characteristics which are different from an ordinary triode gun with a mesh-grid. The mutual conductance gm of 0.4[mS], the maximum average current of 1.6[A] and cut-off voltage -200[V] were obtained under a condition of 200[kV] acceleration voltage. (author)

Application of electron beam equipment based on a plasma cathode gun in additive technology

Science.gov (United States)

Galchenko, N. K.; Kolesnikova, K. A.; Semenov, G. V.; Rau, A. G.; Raskoshniy, S. Y.; Bezzubko, A. V.; Dampilon, B. V.; Sorokova, S. N.

2016-11-01

The paper discusses the application of electron beam equipment based on a plasma cathode gun for three-dimensional surface modification of metals and alloys. The effect of substrate surface preparation on the adhesion strength of gas thermal coatings has been investigated.

Geometry Optimization of DC/RF Photoelectron Gun

CERN Document Server

Chen Ping; Yu, David

2005-01-01

Pre-acceleration of photoelectrons in a pulsed, high voltage, short, dc gap and its subsequent injection into an rf gun is a promising method to improve electron beam emittance in rf accelerators. Simulation work has been performed in order to optimize the geometric shapes of a dc/rf gun and improve electron beam properties. Variations were made on cathode and anode shapes, dc gap distance, and inlet shape of the rf cavity. Simulations showed that significant improvement on the normalized emittance (< 1 mm-mrad), compared to a dc gun with flat cathode, could be obtained after the geometric shapes of the gun were optimized.

CEBAF 200 kV Inverted Electron Gun

International Nuclear Information System (INIS)

Grames, J.M.; Adderley, P.A.; Clark, J.; Hansknecht, J.; Poelker, M.; Stutzman, M.L.; Suleiman, R.; Surles-Law, K.E.L.

2011-01-01

Two DC high voltage GaAs photoguns have been built at Jefferson Lab based on a compact inverted insulator design. One photogun provides the polarized electron beam at CEBAF and operates at 130 kV bias voltage. The other gun is used for high average current lifetime studies at a dedicated test facility and has been operated at bias voltage up to 225 kV. The advantages of higher DC voltage for CEBAF include reduced space-charge emittance growth and the potential for prolonged photocathode lifetime. However, a consequence of operating at higher voltages is the increased likelihood of field emission or breakdown, both of which are unacceptable. Highlights of the R and D studies leading toward a production 200keV GaAs photogun for CEBAF will be presented.

Piercing and Tattoos - Multiple Languages

Science.gov (United States)

... Are Here: Home → Multiple Languages → All Health Topics → Piercing and Tattoos URL of this page: https://medlineplus. ... V W XYZ List of All Topics All Piercing and Tattoos - Multiple Languages To use the sharing ...

Progress on Using NEA Cathodes in an RF Gun

CERN Document Server

Fliller, Raymond P; Blüm, Hans; Edwards, Helen; Hüning, Markus; Schultheiss, Tom; Sinclair, Charles K

2005-01-01

RF guns have proven useful in multiple accelerator applications, and are an attractive electron source for the ILC. Using a NEA GaAs photocathode in such a gun allows for the production of polarized electron beams. However the lifetime of a NEA cathode in this environment is reduced by ion and electron bombardment and residual gas oxidation. We report progress made with studies to produce a RF gun using a NEA GaAs photocathode to produce polarized electron beams. Attempts to reduce the residual gas pressure in the gun are discussed. Initial measurements of ion flux through the cathode port are compared with simulations of ion bombardment. Future directions are also discussed.

Body piercing: complications and prevention of health risks.

Science.gov (United States)

Holbrook, Jaimee; Minocha, Julia; Laumann, Anne

2012-02-01

Body and earlobe piercing are common practices in the USA today. Minor complications including infection and bleeding occur frequently and, although rare, major complications have been reported. Healthcare professionals should be cognizant of the medical consequences of body piercing. Complications vary depending on the body-piercing site, materials used, experience of the practitioner, hygiene regimens, and aftercare by the recipient. Localized infections are common. Systemic infections such as viral hepatitis and toxic shock syndrome and distant infections such as endocarditis and brain abscesses have been reported. Other general complications include allergic contact dermatitis (e.g. from nickel or latex), bleeding, scarring and keloid formation, nerve damage, and interference with medical procedures such as intubation and blood/organ donation. Site-specific complications have been reported. Oral piercings may lead to difficulty speaking and eating, excessive salivation, and dental problems. Oral and nasal piercings may be aspirated or become embedded, requiring surgical removal. Piercing tracts in the ear, nipple, and navel are prone to tearing. Galactorrhea may be caused by stimulation from a nipple piercing. Genital piercings may lead to infertility secondary to infection, and obstruction of the urethra secondary to scar formation. In men, priapism and fistula formation may occur. Women who are pregnant or breastfeeding and have a piercing or are considering obtaining one need to be aware of the rare complications that may affect them or their child. Though not a 'complication' per se, many studies have reported body piercing as a marker for high-risk behavior, psychopathologic symptoms, and anti-social personality traits. When it comes to piercing complications, prevention is the key. Body piercers should take a complete medical and social history to identify conditions that may predispose an individual to complications, and candidates should choose a

An inverted-geometry, high voltage polarized electron gun with UHV load lock

International Nuclear Information System (INIS)

Breidenbach, M.; Foss, M.; Hodgson, J.; Kulikov, A.; Odian, A.; Putallaz, G.; Rogers, H.; Schindler, R.; Skarpaas, K.; Zolotorev, M.

1994-01-01

The design of a high voltage electron source with a GaAs photocathode and a load lock system is described. The inverted high voltage structure of the gun permits a compact and simple design. Test results demonstrate that the load lock system provides a reliable way to achieve high quantum efficiency of the photocathode in a high voltage device. ((orig.))

Oral piercings among first-year university students.

Science.gov (United States)

Ventä, Irja; Lakoma, Ani; Haahtela, Sauli; Peltola, Jaakko; Ylipaavalniemi, Pekka; Turtola, Lauri

2005-05-01

The aim of the study was to examine oral piercings among first-year university students. First-year university students in 2002 were invited to a dental examination (n = 234; 49 men and 185 women). Students with piercings formed the study group and the rest served as controls. The methods included decayed, missing, and filled teeth (DMF) index, stimulated salivary flow rates, panoramic tomograms, and questionnaires including the Depression Inventory of Beck. Fisher's 2-sided exact test was used for statistical analysis. The prevalence of oral piercings was 3.4%. In the DMF indices, no statistically significant differences existed between the groups. Increased salivary flow rates were noted among students with piercings (63% vs 26%, P piercings is essential.

Oral piercings: immediate and late complications.

Science.gov (United States)

Vieira, Elma P; Ribeiro, Andre Luis Ribeiro; Pinheiro, João de Jesus V; Alves, Sérgio de M

2011-12-01

Oral piercings have a long history as part of religious, cultural, or sexual symbolism in many traditional tribes; currently, these ornaments have wide acceptance among young people. Several oral and systemic complications may be associated with this practice; however, limited data related to these complications can be obtained in the literature. This study includes 42 cases of oral piercings in 39 young adults, who were using or had used oral piercings, and the complications associated with their use. Immediate complications occurred in 29 cases, including excessive bleeding (69%) and pain (52.3%) as the most representative. Two cases of syncope were found. Late complications related to the piercing insertion site were observed in 97.6% of cases, with pain and swelling being present in 92.9% and 61.9% of cases, respectively. Dental pain and lacerations on the tongue represented the most prevalent complications associated with the surrounding tissues, accounting for 33.3% and 31% of cases. The use of oral piercings is related to a series of mainly local complications, and individuals who decide to use piercings should be aware of such complications. Individuals wishing to get a part of their body pierced should do so with qualified professionals and should regularly visit the dentist so that a regular control is achieved, thus ensuring the early detection of the adverse effects associated with this practice. Copyright © 2011 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

A compact CMA spectrometer with axially integrated hybrid electron-ion gun for ISS, AES and sputter depth profile analysis

International Nuclear Information System (INIS)

Gisler, E.; Bas, E.B.

1986-01-01

Until now, the combined application of electrons and ions in surface analysis required two separate sources for electrons and ions with different incidence angles. The newly developed hybrid electron-ion gun, however, allows bombardment of the same sample area both with noble gas ions and with electrons coming from the same direction. By integrating such a hybrid gun axially in a cylindrical mirror energy analyser (CMA) a sensitive compact single flange spectrometer obtains for ion scattering spectroscopy (ISS), Auger electron spectroscopy (AES), and sputtering all within normal beam incidence. This concept makes accurate beam centering very easy. Additionally, the bombardment from the same direction both for sputtering and for surface analysis brings advantages in depth profiling. The scattering angle for ISS has a constant value of about 138 0 . The hybrid gun delivers typically an electron beam current of -20μA at 3keV for AES, and an ion beam current of +40 nA and +1.2μA at 2 keV for ISS and sputtering respectively. The switching time between ISS, AES, and sputtering mode is about 0.1 s. So this system is best suited for automatically controlled depth profile analysis. The design and operation of this new system will be described and some applications will be discussed. (author)

Synthesis method for using in the design of an electron gun for gyrotion

International Nuclear Information System (INIS)

Silva, C.A.B.

1987-09-01

In this work a synthesis method is applied to the design of an electron gun for a 94GHz gyrotron. Using the synthesis method, it is found the shape of the electrodes compatible with the laminar flow which minimizes the action of space change on the electron velocity dispersion. A sistematic procedure is presented to fuid the parameters of the synthesis method which, in turn, are closely related to the characteristics of the aptoclechonic system. (author) [pt

Electron ray tracing programs for gun design and beam transport

International Nuclear Information System (INIS)

Herrmannsfeldt, W.B.

1988-05-01

Computer simulation of electron and ion sources is made by using a class of computer codes known as gun design programs. In this paper, we shall first list most of the necessary and some optional capabilities of such programs. Then we will briefly note specific codes and/or authors of codes with attention to specialized applications if any. There may be many more such programs in use than are treated here; we are only trying to cover a range of examples, not perform a comprehensive survey

Function of bunching segment in multi-cell RF gun

International Nuclear Information System (INIS)

Yang Xingfan; Xu Zhou Liu Xisan

2001-01-01

With a bunching segment and a shortened first cell, the 4 + 1/2 cell RF gun produced in CAEP has been proved experimentally to be effective in reducing electron back bombardment. The analysis of the electric field distribution and electron motion in bunching segment of multi-cell RF gun is presented. The electron capture efficiency and electron trajectory with different initial phase are calculated using Runge-Kutta method. The function of the bunching segment is discussed. The calculated parameters of the 4 + 1/2 cell RF gun agree well with the experimental results

Intimate body piercings in women

NARCIS (Netherlands)

van der Meer, G. T.; Schultz, W. C. M. Weijmar; Nijman, J. M.

2008-01-01

The popularity of (intimate) body piercing has increased as well as the chances of being confronted with (the complications) of it. This article provides information about the various types of intimate body piercings in women, the complications and concerns regarding the treatment of patients with

Pierce electrodes for a multigap accelerating system

International Nuclear Information System (INIS)

Davydenko, V.I.; Ivanov, A.A.; Kotelnikov, I.A.; Tiunov, M.A.

2007-01-01

A well-known Pierce's solution that allows to focus a beam of charged particles using properly shaped electrodes outside the beam is generalized to the case of multigap accelerating system. Simple parametric formulae for Pierce electrodes are derived for an accelerating system with current density, limited either by space charge or by emitting property of the cathode. As an example of general approach, Pierce electrodes shape is analyzed for a system with two accelerating gaps. It is shown that precise Pierce's solution exists if acceleration rate within second gap is lower than within first gap. In the opposite case quasi-Pierce solution can be implemented using non-equipotential electrode between the gaps, and guidelines, based on numerical simulations, for the design of equipotential focusing electrodes are given

Study of Control Grid Thermionic Cathode RF Gun

CERN Document Server

Xiao, Jin; Ming, Li; Xinfan, Yang; Xumin, Shen; Yanan, Chen; Zhou, Xu

2004-01-01

In this paper, the beam loading effect of RF Gun was analyzed. To minimize the energy spread, the grid control RF Gun was introduced. The result shows that the grid congrol RF Gun can increase electron beam within 1% energy spread.

An isolated grid electron gun and pulser system for long/short pulse operation

International Nuclear Information System (INIS)

Koontz, R.F.; Feathers, L.; Kilbourne, C.; Leger, G.; McKinney, T.

1984-01-01

The new NPI gun at SLAC serves the dual functions of producing long pulse (up to 5 μsec, 180 pps) electron bursts for nuclear physics experiments, and also short ( 1 nsec) pulses for filling Stanford Synchrotron Radiation Laboratory (SSRL). This is accomplished by means of a newly designed, isolated grid gun, cathode pulsed with a solid state long pulse pulser, and grid pulsed with a fast recharging avalanche type short pulse (1 nsec) grid pulser. The grid pulser is bipolar so that a fast blackout notch can be placed in the long cathode pulse. This fast notch can be seen by Stanford Linear Collider (SLC) instrumentation and allows the long pulse beam to be computer controlled by SLC intensity and beam position monitors. (orig.)

RF Design and Operating Performance of the BNL/AES 1.3 GHz Single Cell Superconducting RF Photocathode Electron Gun

International Nuclear Information System (INIS)

Cole, Michael; Kneisel, Peter; Ben-Zvi, Ilan; Burrill, Andrew; Hahn, H.; Rao, Triveni; Zhao, Y.

2005-01-01

Over the past several years Advanced Energy Systems and BNL have been collaborating on the development and testing of a fully superconducting photocathode electron gun. Over the past year we have begun to realize significant results which have been published elsewhere (1). This paper will review the RF design of the gun under test and present results of its performance under various operating conditions. Results for cavity quality factor will be presented for various operating temperatures and cavity field gradients. We will also discuss future plans for testing using this gun.

Pericondrite pós-piercing Post-piercing perichondritis

Directory of Open Access Journals (Sweden)

André de Paula Fernandez

2008-12-01

Full Text Available O uso de piercing tem se tornado uma prática muito freqüente entre os jovens. O procedimento na maioria vezes realizado por profissionais não-qualificados não é isento de riscos. O manuseio de material contaminado ou a higiene imprópria predispõem à pericondrite e à celulite. A pericondrite caracteriza-se pelo eritema do pavilhão auricular, dor intensa e febre. Sem tratamento, desenvolve-se um edema generalizado do pavilhão com formação de abscesso subpericondrial, podendo evoluir para necrose isquêmica da cartilagem e a temível deformidade estética conhecida como "orelha em couve flor". O agente responsável mais encontrado é o Pseudomonas aeruginosa. No estágio inicial da doença o tratamento pode ser feito com antibióticos de amplo espectro. Nos casos em que o abscesso está presente, a incisão e drenagem cirúrgica são obrigatórios acompanhado de antibioticoterapia guiado pela cultura e antibiograma. OBJETIVO: O objetivo deste relato de caso é realizar uma revisão bibliográfica dos últimos 10 anos abordando os aspectos anatômicos do pavilhão auricular, a história do uso de piercing e suas mais conhecidas complicações. MÉTODO: Relato de um caso de pericondrite pós-piercing transcartilaginoso onde houve a necessidade de tratamento cirúrgico com praticamente nenhuma deformidade estética. RESULTADO: Aquisição de experiência teórico-prática através de revisão bibliográfica e relato de um caso de evolução favorável para a paciente. CONCLUSÃO: Incidência crescente das complicações de pericondrites na população jovem deve levar à prevenção primária mais elaborada.Piercing has become more and more popular among adolescents. The procedure is generally performed by unqualified professionals and carries its risk. Non-sterilized material or inappropiate hygiene increases the possibility of perichondritis and celulitis. The disease is characterized by erythema of the auricula pinna, unbearable pain

Development, construction and characterization of a variable repetitive spin-polarized electron gun with an inverted-geometry insulator

International Nuclear Information System (INIS)

Espig, Martin

2016-02-01

Within the scope of this thesis a pulsed source of spin polarized electrons Photo-CATCH was designed, constructed, characterized and has been put into operation. This source is based on the photoemission of spin-polarized electrons from GaAs-photocathodes. Both the design of the electron gun, consisting of an ultra-high vacuum chamber and an electrode with Pierce geometry, as well as the properties of the electron beam have been simulated with CST Studio. Results were a maximum electric field of (0.064±0.001) MV/m/kV on the electrode surface and a beam emittance as a function of the radius of the laser spot on the photocathode of element of _n_,_x=(1.7478(4).10"-"4.(r)/(μm)+2.8(18).10"-"5) mm mrad at a beam current of 100 μA. Currently Photo-CATCH provides electron beams with an energy of 60 keV, which can be expanded up to 100 keV by upgrading the high-voltage power supply. The electron gun has an inverted-geometry insulator to ensure a compact design of the ultra-high vacuum chamber and a maximum person- and machine-safety from sparkovers. Since the properties of the laser light directly affect the properties of the generated electron beam a pulsed semiconductor laser system has been specially developed and built for Photo-CATCH. This is characterized by a high variability of its operating parameters, in particular its wavelength and repetition rate, in order to fulfill the broad variety of requirements of various nuclear physics experiments. By selecting the wavelength of the used laser diode highly polarized or high-current electron beams can be generated from GaAs-photocathodes. The time profile of the laser has direct influence to the longitudinal profile of the electron bunch. Through the radiofrequency modulation of the pumping current of the impedance-matched semiconductor laser system, consisting of a DC power source and an electrical pulse generator with 881 ps broad pump pulses, Lorentz shaped laser pulses with a minimum FWHM of (43.8±1.2) ps at a

Intimate body piercings in women.

Science.gov (United States)

van der Meer, G T; Schultz, W C M Weijmar; Nijman, J M

2008-12-01

The popularity of (intimate) body piercing has increased as well as the chances of being confronted with (the complications) of it. This article provides information about the various types of intimate body piercings in women, the complications and concerns regarding the treatment of patients with intimate bodypiercings.

Diagrammer hos Pierce og Deleuze

DEFF Research Database (Denmark)

Busk, Malene

2006-01-01

Artiklen omhandler to forskellige begreber om diagrammet, nemlig Pierces og Deleuzes. De definerer udfra to meget forskellige udgangspukter begge diagrammet som kreativt redskab......Artiklen omhandler to forskellige begreber om diagrammet, nemlig Pierces og Deleuzes. De definerer udfra to meget forskellige udgangspukter begge diagrammet som kreativt redskab...

Self-piercing riveting properties, processes and applications

CERN Document Server

Chrysanthou, A

2014-01-01

Due to its speed, low energy requirements, and the fact that it does not require a pre-drilled hole, the technique of self-piercing riveting (SPR) has been increasingly adopted by many industries as a high-speed mechanical fastening technique for the joining of sheet material components. Self-piercing riveting comprehensively reviews the process, equipment, and corrosion behaviour of self-piercing riveting, and also describes the process of evaluation and modelling of strength of self-piercing riveted joints, quality control methods and non-destructive testing.Part one provides an exte

Post-piercing perichondritis.

Science.gov (United States)

Fernandez, André de Paula; Castro Neto, Ivan de; Anias, Christiane Ribeiro; Pinto, Patrícia Ciminelli Linhares; Castro, Jair de Carvalho E; Carpes, Arturo Frick

2008-01-01

Piercing has become more and more popular among adolescents. The procedure is generally performed by unqualified professionals and carries its risk. Non-sterilized material or inappropiate hygiene increases the possibility of perichondritis and celulitis. The disease is characterized by erythema of the auricula pinna, unbearable pain and fever. Left untreated, the condition progresses with edema along the auricula and abscess formation that may result in ischemic necrosis and a cauliflower anesthetic deformation. The most common bacteria is Pseudomonas aeruginosa. In cases with abscesses, drainage is necessary along with antibiotic therapy guided by cultures and antibiogram. The aim of this case report was to review the past 10 years of published papers dealing with anatomical aspects of the auricular pinna, the history of piercing and its most common complications. A case report of perichondritis after 'high' ear piercing that required surgical treatment and that progressed with no esthetic loss. Theoretical and practical experience based on a review and a report of a case that progressed satisfactorily. The increased incidence of perichondritis in adolescents should require more elaborated primary prevention measures.

Generation of helical electron beams by a nonadiabatic gun

International Nuclear Information System (INIS)

Barroso, J.J.; Stellati, C.

1996-01-01

The design of a non-adiabatic gun to produce a 10A, 50kV hollow laminar electron beam for gyrotron applications is reported. The beam is extracted from the emitting ring in a direction parallel to the axial guide magnetic field and then propagates across the radial electric field in the anode gap. The electrons are thereby given a transverse velocity upon passing through the modulation anode region where an electrostatic pumping mechanism takes place, so that a considerable amount of the electron energy is converted to transverse kinetic energy. Such a beam extraction method gives rise to favourable features that are examined throughout the work. The dynamics of hollow electron beams with gyromotion propagating down a cylindrical drift tube are also analysed. Due to the action of the beam's self-space charge field, the transverse velocity spread has an oscillatory behaviour along the drift tube wherein the spatial automodulation period shortens with increasing current. Numerical simulation results indicate that even at a 10A beam current, the resulting transverse velocity spread is still less than the spread for a zero beam current. (UK)

[Tattoos and piercings in adolescents: family conflicts and temperament].

Science.gov (United States)

Bosello, Romina; Favaro, Angela; Zanetti, Tatiana; Soave, Manuela; Vidotto, Giulio; Huon, Gail; Santonastaso, Paolo

2010-01-01

The phenomenon of body art, such as tattoos and piercings, has ancient roots, rediscovered in Western society during the '70s. The aim of this research is to investigate the prevalence and the characteristics of tattoos and piercings among Italian adolescents of high school in Padua, with particular attention to family context and temperament. Some questionnaires about the presence or the wish of tattoos/piercings, smoke and alcohol use, familiar conflicts, and some temperamental features, such as novelty seeking, harm avoidance and reward dependence, have been administered to a sample of 829 students. Tattoo and piercing's prevalence among adolescents was respectively 4% and 24%; 2.5% of the sample had both. Respectively 62% and 35% of the subjects expressed the desire of having a tattoo or piercing. A significant association has been found between tattoo/piercing's presence and smoke and alcohol use (p tattoos and piercings, are more likely to have familiar conflicts and minor perceived support and they have higher scores on the novelty seeking scale. Those who wish a tattoo/piercing showed higher reward dependence. This study confirms that tattoos/piercings are common among young people and it stresses the relevance of familiar and temperamental features, and the association between tattoos/piercings and some maladaptive behaviors, like smoke and alcohol use.

Analysis of Premature Wear-Out of Aircraft Gun Barrel by Applying a Transmission Electron Microscopy (TEM

Directory of Open Access Journals (Sweden)

Łęczycki Krzysztof

2017-08-01

Full Text Available Firing from gun armament generates a wide range of physico-chemical phenomena contributing to the degradation of barrel material, e.g. pressure, high temperature, chemically aggressive character of post-detonation gases and friction of a driving band. In this work the technique of thin foils was used in Transmission Electron Microscopy (TEM to study the influence of physicochemical phenomena on the material microstructure of aircraft gun barrel. A mechanism and reason of premature wear-out of the barrel under consideration was also outlined by utilising light microscopy and hardness measurements.

Characteristics of the ETA gun

International Nuclear Information System (INIS)

Paul, A.C.; Neil, V.K.; Craig, G.D.; Fessenden, T.J.

1981-01-01

The Experimental Test Accelerator (ETA) is a linear induction device consisting of a 2.5-MV electron gun and ten 0.25-MV accelerating units designed to produce a 10-kA beam of electrons at 5 MeV. Calculations with the computer code EBQ as well as experimental measurements indicate that the current produced by the gun is limited by two phenomena. The first arises from the variation of particle energy with time during the pulse. Only particles with energy within a limited range can be transported by the focusing coils in the gun: therefore the variation of the gun's output current with time is determined by the coil settings. The second effect results from a collective interaction at sufficiently large current to cause a virtual cathode to form a few centimeters past the extraction grid. Operation in this regime results in greatly increased beam emittance and poor beam transport through the accelerator. Results of the code calculations are compared with experimental data and found to be in good agreement. (author)

[Piercings. A new demand for nursing].

Science.gov (United States)

Lastra Félix, Marcos

2004-03-01

The new legal regulations and agreements dealing with the type of locales and personnel authorized to implant body rings through pierced holes known popularly as piercings brings with it the need for nurses to learn about this practice and to adapt our habitual sanitary techniques, in an urgent manner, in order to cover the increasing aesthetic demand. The nursing profession needs to amplify its range of treatments for this piercing practice so it is not limited to merely inserting rings or studs in holes.

Conceptual Design for CLIC Gun Pulser

Energy Technology Data Exchange (ETDEWEB)

Tang, Tao [SLAC National Accelerator Lab., Menlo Park, CA (United States)

2016-01-08

The Compact Linear Collider (CLIC) is a proposed future electron-positron collider, designed to perform collisions at energies from 0.5 to 5 TeV, with a nominal design optimized for 3 TeV (Dannheim, 2012). The Drive Beam Accelerator consists of a thermionic DC gun, bunching section and an accelerating section. The thermionic gun needs deliver a long (~143us) pulse of current into the buncher. A pulser is needed to drive grid of the gun to generate a stable current output. This report explores the requirements of the gun pulser and potential solutions to regulate grid current.

Dental and oral complications of lip and tongue piercings.

Science.gov (United States)

De Moor, R J G; De Witte, A M J C; Delmé, K I M; De Bruyne, M A A; Hommez, G M G; Goyvaerts, D

2005-10-22

Piercing of the tongue and perioral regions is an increasingly popular expression of body art, with more patients coming in for a routine check-up with tongue and/or lip piercings. Several complications of oral piercing have been reported, some of which are life-threatening. In the present clinical survey the prevalence of both tongue and lip piercing complications in oral health was assessed in a group of 50 patients. The most common dental problem registered was chipping of the teeth, especially in association with tongue piercing. Gingival recession was seen as a result of lip piercing with studs. Post-procedural complications included oedema, haemorrhage and infection. Therefore, dentists and oral and maxillofacial surgeons should be given more authority to advise patients with oral and facial piercings or those who plan to acquire this type of body art.

Examination of the spatial-response uniformity of a microchannel-plate detector using a pulsed high-voltage electron gun

International Nuclear Information System (INIS)

Alumot, D; Kroupp, E; Fisher, A

2014-01-01

In this paper we describe an alternative method to examine the spatial-response uniformity of a microchannel-plate (MCP) detector to a ∼ 1 ns pulse of soft x-rays. The examination was performed by illuminating the MCP surface with energetic electrons rather than with x-rays. It is shown that the MCP features similar, yet not identical, response to pulses of soft x-ray photons or energetic electrons, making such examinations much simpler and less expensive. The building of the electron-gun system is relatively easy and inexpensive, and in addition to verifying the spatial uniformity of the response of the MCP to incoming particles and radiation, it can be used to detect damaged areas on the detector. A comparison between the results obtained using the electron-gun with those obtained using a laser-produced-plasma x-ray source, demonstrating the reliability of the method, is presented

Enhancement of ECR performances by means of carbon nano-tubes based electron guns

International Nuclear Information System (INIS)

Odorici, F.; Cuffiani, M.; Malferrari, L.; Rizzoli, R.; Veronese, G.P.; Celona, L.; Gammino, S.; Mascali, D.; Miracoli, R.; Romano, F.P.; Gambino, N.; Castro, G.; Ciavola, G.; Serafino, T.

2012-01-01

The CANTES experiment at INFN-LNS tested the use of carbon nano-tubes (CNTs) to emit electrons by field emission effect, in order to provide additional electrons to the plasma core of an ECR ion source. This technique was used with the Caesar source, demonstrating that the total extracted ion current is increased and that a relevant reduction of the number of 'high energy' electrons (above 100 keV) may be observed. The injection of additional electrons inside the plasma increases the amount of cold and warm electrons, and then the number of ionizing collisions. Details of the construction of CNTs based electron gun and of the improvement of performances of the Caesar ECR ion source will be presented. The paper is followed by the associated poster. (authors)

Body adornment: piercings and tattoos.

Science.gov (United States)

Chivers, Lesley

Body adornment through tattoos and piercings is on the increase, making adverse side effects more common. Practitioners should be prepared to give advice, either before the event, or post-procedure in written and oral forms. The aim of this article is to inform practitioners of the sites and types of piercings, likely adverse side effects and estimated healing times.

Gun ownership and social gun culture.

Science.gov (United States)

Kalesan, Bindu; Villarreal, Marcos D; Keyes, Katherine M; Galea, Sandro

2016-06-01

We assessed gun ownership rates in 2013 across the USA and the association between exposure to a social gun culture and gun ownership. We used data from a nationally representative sample of 4000 US adults, from 50 states and District of Columbia, aged >18 years to assess gun ownership and social gun culture performed in October 2013. State-level firearm policy information was obtained from the Brady Law Center and Injury Prevention and Control Center. One-third of Americans reported owning a gun, ranging from 5.2% in Delaware to 61.7% in Alaska. Gun ownership was 2.25-times greater among those reporting social gun culture (PR=2.25, 95% CI 2.02 to 2.52) than those who did not. In conclusion, we found strong association between social gun culture and gun ownership. Gun cultures may need to be considered for public health strategies that aim to change gun ownership in the USA. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Water gun vs air gun: A comparison

Science.gov (United States)

Hutchinson, D.R.; Detrick, R. S.

1984-01-01

The water gun is a relatively new marine seismic sound source that produces an acoustic signal by an implosive rather than explosive mechanism. A comparison of the source characteristics of two different-sized water guns with those of conventional air guns shows the the water gun signature is cleaner and much shorter than that of a comparable-sized air gun: about 60-100 milliseconds (ms) for an 80-in3. (1.31-liter (I)) water gun compared with several hundred ms for an 80-in3. (1.31-1) air gun. The source spectra of water guns are richer in high frequencies (>200 Hz) than are those of air guns, but they also have less energy than those of air guns at low frequencies. A comparison between water gun and air gun reflection profiles in both shallow (Long Island Sound)-and deep (western Bermuda Rise)-water settings suggests that the water gun offers a good compromise between very high resolution, limited penetration systems (e.g. 3.5-kHz profilers and sparkers) and the large volume air guns and tuned air gun arrays generally used where significant penetration is required. ?? 1984 D. Reidel Publishing Company.

A device for determination of the electrical potential of a rocket carrying an electron gun

International Nuclear Information System (INIS)

Gringauz, K.I.; Musatov, L.S.; Shutte, N.M.; Beliashin, A.P.; Denstchikova, L.I.; Kopilov, V.F.

1978-01-01

Data on the principle of operation, sensors and electronics of a device for determination of the electrical potential relative to the surrounding medium of a rocket carrying an electric gun are presented. The device operated successfully on board an Eridan rocket during the ARAKS experiment. (Auth.)

[Cutaneous adverse reactions to tattoos and piercings].

Science.gov (United States)

Mataix, J; Silvestre, J F

2009-10-01

Piercings and tattoos have become very popular in western society in recent decades, particularly among younger generations. Reports of medical complications associated with these decorative techniques have increased in parallel with the rise in their popularity. Due to their high frequency, adverse cutaneous reactions are particularly important among these potential complications. Tattoo-related complications include a number of cutaneous and systemic infections secondary to breach of the epidermal barrier, acute and delayed inflammatory reactions with different histopathological patterns, the appearance of benign and malignant tumors on tattooed areas of skin, and certain dermatoses triggered by isomorphic phenomena. Piercing-related complications are similar, though some, such as pyogenic skin infections, are much more common due to the delayed wound healing after piercing in certain sites. We must differentiate between complications that are independent of the site of piercing, and specific complications, which are closely related to the body area pierced. The rate of complications after performing piercings or tattoos depends on the experience of the artist, the hygiene techniques applied, and the postprocedural care by the customer. However, some of these complications are unpredictable and depend on factors intrinsic to the patient. In this article, we review the most common decorative techniques of body art, with particular focus on the potential cutaneous complications and their management.

Low power microwave tests on RF gun prototype of the Iranian Light Source Facility

Directory of Open Access Journals (Sweden)

A Sadeghipanah

2017-08-01

Full Text Available In this paper, we introduce RF electron gun of Iranian Light Source Facility (ILSF pre-injection system. Design, fabrication and low-power microwave tests results of the prototype RF electron gun have been described in detail. This paper also explains the tuning procedure of the prototype RF electron gun to the desired resonant frequency. The outcomes of this project brighten the path to the fabrication of the RF electron gun by the local industries  

Effects of pulse-length and emitter area on virtual cathode formation in electron guns

International Nuclear Information System (INIS)

Valfells, Agust; Feldman, D.W.; Virgo, M.; O'Shea, P.G.; Lau, Y.Y.

2002-01-01

Recent experiments at the University of Maryland using photoemission from a dispenser cathode have yielded some interesting results regarding the effects of the area of emission and of the ratio between the pulse length and the gap transit time on the amount of current that may be drawn from an electron gun before a virtual cathode forms. The experiments show that a much higher current density may be drawn from a short pulse or limited emitter area than is anticipated by the Child-Langmuir limiting current. There is also evidence that the current may be increased even after virtual cathode formation, which leads a distinction between a limiting current density and a current density critical for virtual cathode formation. The experiments have also yielded some interesting results on the longitudinal structure of the current pulse passed through the anode. Some empirical and theoretical scaling laws regarding the formation of virtual cathodes in an electron gun will be presented. This work was motivated by the needs of the University of Maryland Electron Ring (UMER) [P. G. O'Shea, M. Reiser, R. A. Kishek et al., Nucl. Instrum. Methods Phys. Res. A 464, 646 (2001)] where the goal is to generate pulses that are well-localized in time and space

SSRL photocathode RF gun test stand

International Nuclear Information System (INIS)

Hernandez, M.; Baltay, M.; Boyce, A.

1995-01-01

A photocathode RF gun test stand designed for the production and study of high brightness electron beams will be constructed at SSRL. The beam will be generated from a laser driven third generation photocathode RF gun being developed in collaboration with BNL, LBL, and UCLA. The 3-5 [MeV] beam from the gun will be accelerated using a SLAC three meter S-band accelerator section, in order to achieve the desired low emittance beam, emittance compensation with solenoidal focusing will be employed

Fibre optic control for electron gun power supplies and data acquisition of 3 MeV DC accelerator

International Nuclear Information System (INIS)

Chavan, R.B.; Yadav, Vivek; Dixit, K.P.; Bakhtsingh, R.I.; Rajan, Rehim; Nanu, K.; Mittal, K.C.; Chakravarthy, D.P.; Gantayet, L.M.

2011-01-01

A 3 MeV, 10 mA DC Industrial Electron Beam Accelerator is being commissioned at Electron Beam Centre, Navi Mumbai. The electron beam is generated by a triode electron gun and injected into the accelerating column at 5 keV. The gun and its power supplies, (5 kV anode, 3 kV grid and 15V/20A filament), are floating at 3 Million volts, and are situated in a tank which is pressurized with SF6 at 6 kg/cm 2 . These power supplies are required to be controlled remotely. The various accelerator parameters like Beam Energy, Beam Current, RF Electrode Voltage, Power Oscillator Plate Voltage / Current and Vacuum are required to be monitored during beam operation. The software was developed in VB.Net for control and data acquisition. The database is provided in SQL 2005 for storing the data. For this purpose, control system using ADAM modules and Optical fibre has been designed and developed. This paper describes the design features of the control system and experience of use of control software during initial beam trials. (author)

Current control of the electron beam formed in the magnetron gun with a secondary-emission cathode

International Nuclear Information System (INIS)

Dovbnya, A.N.; Reshetnyak, N.G.; Zakutin, V.V.; Chertishchev, I.A.; Romas'ko, V.P.; Dovbnyan, N.A.

2013-01-01

Data are reported on electron beam generation and beam current control in two types of secondary-emission cathode magnetron guns. The influence of the magnetic field value and field distribution on the formation of the beam and its parameters has been investigated in the electron energy range between 20 and 150 keV. The influence of local magnetic field variations on the cathode and the electron beam characteristics has been studied. The possibility to control the electron beam current in various ways has been demonstrated

The Development of the Linac Coherent Light Source RF Gun

International Nuclear Information System (INIS)

Dowell, D

2008-01-01

The Linac Coherent Light Source (LCLS) is the first x-ray laser user facility based upon a free electron laser (FEL) requiring extraordinary beam quality to saturate at 1.5 angstroms within a 100 meter undulator.[1] This new type of light source is using the last kilometer of the three kilometer linac at SLAC to accelerate the beam to an energy as high as 13.6 GeV and required a new electron gun and injector to produce a very bright beam for acceleration. At the outset of the project it was recognized that existing RF guns had the potential to produce the desired beam but none had demonstrated it. Therefore a new RF gun or at least the modification of an existing gun was necessary. The parameters listed in Table 1 illustrate the unique characteristics of LCLS which drive the requirements for the electron gun as given in Table 2. The gun beam quality needs to accommodate emittance growth as the beam is travels through approximately one kilometer of linac and two bunch compressors before reaching the undulator. These beam requirements were demonstrated during the recent commissioning runs of the LCLS injector and linac [2] due to the successful design, fabrication, testing and operation of the LCLS gun. The goal of this paper is to relate the technical background of how the gun was able to achieve and in some cases exceed these requirements by understanding and correcting the deficiencies of the prototype s-band RF photocathode gun, the BNL/SLAC/UCLA Gun III. This paper begins with a brief history and technical description of Gun III and the Gun Test Facility (GTF) at SLAC, and studies of the gun's RF and emittance compensation solenoid. The work at the GTF identified the gun and solenoid deficiencies, and helped to define the specifications for the LCLS gun. Section 1.1.5 describes the modeling used to compute and correct the gun RF fields and Section 1.1.6 describes the use of these fields in the electron beam simulations. The magnetic design and measurements of

TU-H-BRA-03: Performance of a Clinical Gridded Electron Gun in Magnetic Fields: Implications for MRI-Linac Therapy

International Nuclear Information System (INIS)

Whelan, B; Keall, P; Bazalova-Carter, M; Oborn, B; Constantin, D; Holloway, L; Fahrig, R

2016-01-01

Purpose: Recent advances towards MRI Linac radiotherapy have motivated a wide range of studies characterizing electromagnetic interactions between the two devices. One of the most sensitive components is the linac electron gun. To data, only non gridded (diode) guns have been investigated however, most linac vendors utilize gridded (triode) guns, which enable efficient and robust beam gating. The purpose of this study was to develop a realistic model of a gridded gun used clinically, and to characterize its performance in magnetic fields. Methods: The gridded electron gun used on Varian high energy machines was measured using 3D laser scanning quoted as accurate to 0.1mm. Based on the scane, a detailed CAD mode was developed. From this, key geometry was extracted and a FEM model was developed (Opera/SCALA). Next, the high voltage (HV), grid voltage, and emission current were read from six dose matched TrueBeam linacs for the 6X, 10X and 15X photon modes (0 B-field). The mean values were used to represent each mode, which was simulated I constant magnetic fields from 0–200G in-line, and 0–35G perpendicular. Results: Experimentally measured HV, grid voltage, and emission current from 6X, 10X and 15X modes were respectively: 15±.03kV, 10±.08kV, 11±.03kV; 93±7V, 41±3V, and 70±6V; 327±27mA, 129±10mA, and 214±19mA. The error in simulated emission current of each mode was 3%,6%, and 3%. For in-line fields, 50% beam loss occurred at 114, 96, and 97G; for perpendicular; at 12, 13 and 14G. Sensitivity for a given geometry is primarily determined by HV setting. Conclusion: Future MRI-Linac systems will almost certainly use gridded guns. We present the first model of a clinical gridded gun, and match the experimental emission current to within 6% across three different operating modes. This clinical gun shows increased sensitivity to magnetic fields than previous work,and different modes show different sensitivity.

TU-H-BRA-03: Performance of a Clinical Gridded Electron Gun in Magnetic Fields: Implications for MRI-Linac Therapy

Energy Technology Data Exchange (ETDEWEB)

Whelan, B; Keall, P [University of Sydney, Sydney (Australia); Bazalova-Carter, M [University of Victoria, VCH040, Victoria, BC (Australia); Oborn, B [Illawarra Hospital, Wollongong, NSW (Australia); Constantin, D [Varian Medical Systems, Palo Alto, California (United States); Holloway, L [Liverpool Hospital and Ingham Institute, Liverpool, NSW (United Kingdom); Fahrig, R [Siemens Healthcare GmbH, Forchheim (Germany)

2016-06-15

Purpose: Recent advances towards MRI Linac radiotherapy have motivated a wide range of studies characterizing electromagnetic interactions between the two devices. One of the most sensitive components is the linac electron gun. To data, only non gridded (diode) guns have been investigated however, most linac vendors utilize gridded (triode) guns, which enable efficient and robust beam gating. The purpose of this study was to develop a realistic model of a gridded gun used clinically, and to characterize its performance in magnetic fields. Methods: The gridded electron gun used on Varian high energy machines was measured using 3D laser scanning quoted as accurate to 0.1mm. Based on the scane, a detailed CAD mode was developed. From this, key geometry was extracted and a FEM model was developed (Opera/SCALA). Next, the high voltage (HV), grid voltage, and emission current were read from six dose matched TrueBeam linacs for the 6X, 10X and 15X photon modes (0 B-field). The mean values were used to represent each mode, which was simulated I constant magnetic fields from 0–200G in-line, and 0–35G perpendicular. Results: Experimentally measured HV, grid voltage, and emission current from 6X, 10X and 15X modes were respectively: 15±.03kV, 10±.08kV, 11±.03kV; 93±7V, 41±3V, and 70±6V; 327±27mA, 129±10mA, and 214±19mA. The error in simulated emission current of each mode was 3%,6%, and 3%. For in-line fields, 50% beam loss occurred at 114, 96, and 97G; for perpendicular; at 12, 13 and 14G. Sensitivity for a given geometry is primarily determined by HV setting. Conclusion: Future MRI-Linac systems will almost certainly use gridded guns. We present the first model of a clinical gridded gun, and match the experimental emission current to within 6% across three different operating modes. This clinical gun shows increased sensitivity to magnetic fields than previous work,and different modes show different sensitivity.

A high-gradient high-duty-factor Rf photo-cathode electron gun

International Nuclear Information System (INIS)

Rimmer, Robert A.; Hartman, Neal; Lidia, Steven M.; Wang, Shaoheng

2002-01-01

We describe the analysis and preliminary design of a high-gradient, high-duty factor RF photocathode gun. The gun is designed to operate at high repetition rate or CW, with high gradient on the cathode surface to minimize emittance growth due to space charge forces at high bunch charge. The gun may also be operated in a solenoidal magnetic field for emittance compensation. The design is intended for use in short-pulse, high-charge, and high-repetition rate applications such as linac based X-ray sources. We present and compare the results of gun simulations using different codes, as well as RF and thermal analysis of the structure

A high-gradient high-duty-factor RF photo-cathode electron gun

International Nuclear Information System (INIS)

Rimmer, Robert; Hartman, N.; Lidia, S.; Wang, S.H.

2002-01-01

We describe the analysis and preliminary design of a high-gradient, high-duty factor RF photocathode gun. The gun is designed to operate at high repetition rate or CW, with high gradient on the cathode surface to minimize emittance growth due to space charge forces at high bunch charge. The gun may also be operated in a solenoidal magnetic field for emittance compensation. The design is intended for use in short-pulse, high-charge, and high-repetition rate applications such as linac based X-ray sources. We present and compare the results of gun simulations using different codes, as well as RF and thermal analysis of the structure