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in subjects: "Electron Guns"

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Electron-gun-controlled thin film mirrors for remote sensing applications

The ultimate limitation in obtainable resolution and sensitivity for space-based imaging systems is the size of the optical collecting aperture. Large collecting apertures are at odds with maintaining low launch costs and with current launch vehicle configurations. Development of a deployable mirror is one approach being considered to satisfy these conflicting requirements. The focus of this research is to develop fundamental technology toward the realization of deployable electron-gun-controll… more

Date: February 15, 2000

Creator: HENSON,TAMMY D.; REDMOND,JAMES M.; WEHLBURG,JOSEPH C.; MARTIN,JEFFREY W. & MAIN,JOHN A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

CONCEPTUAL DESIGN OF A BRIGHT ELECTRON INJECTOR BASED ON A LASER-DRIVEN PHOTOCATHODE RF ELECTRON GUN

Conceptual design of a bright electron injector for the 1 GeV high gradient test experiment. envisaged by the LLNL-SLAC-LBL collaboration on the Relativistic Klystron is presented. The design utilizes a high-brightness laser-driven RF photocathode electron gun, similar to the pioneering LANL early studies in concept (different parametrically however), together with achromatic magnetic bunching and transport systems and diagnostics. The design is performed with attention to possible use in an FE… more

Date: September 1, 1988

Creator: Chattopadhyay, S.; Chen, Y. J.; Hopkins, D.; Kim, K. J.; Kung, A.; Miller, R. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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A facility for accelerator research and education at Fermilab

Fermilab is currently constructing the 'SRF Test Accelerator at the New Muon Lab' (NML). NML consists of a photo-emitted RF electron gun, followed by a bunch compressor, low energy test beamlines, SCRF accelerating structures, and high energy test beamlines. The initial primary purpose of NML will be to test superconducting RF accelerating modules for the ILC and for Fermilab's 'Project X' - a proposal for a high intensity proton source. The unique capability of NML will be to test these module… more

Date: January 1, 2009

Creator: Church, Mike & Nagaitsev, Sergei

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Status of Jefferson Lab's Load Locked Polarized Electron Beam

A new 100 kV load locked polarized electron gun has been built at Jefferson Lab. The gun is installed in a test stand on a beam line that resembles the first few meters of the CEBAF nuclear physics photoinjector. With this gun, a GaAs photocathode can be loaded from atmosphere, hydrogen cleaned, activated and taken to high voltage in less than 8 hours. The gun is a three chamber design, with all of the moving parts remaining at ground potential during gun operation. Studies of gun performance, … more

Date: September 1, 2002

Creator: Stutzman, M.L.; Adderley, P.; Baylac, M.; Clark, J.; Day, A.; Grames, J. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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HOM damping properties of fundamental power couplers in the superconducting electron gun of the energy recovery LINAC at Brookhaven National Laboratory

Among the accelerator projects under construction at the Relativistic Heavy Ion Collider (RHIC) is an R and D energy recovery LINAC (ERL) test facility. The ERL includes both a five-cell superconducting cavity as well as a superconducting, photoinjector electron gun. Because of the high-charge and high-current demands, effective higher-order mode (HOM) damping is essential, and several strategies are being pursued. Among these is the use of the fundamental power couplers as a means for damping … more

Date: March 28, 2011

Creator: Hammons, L. & Hahn, H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

DIAMOND AMPLIFIER FOR PHOTOCATHODES.

We report a new approach to the generation of high-current, high-brightness electron beams. Primary electrons are produced by a photocathode (or other means) and are accelerated to a few thousand electron-volts, then strike a specially prepared diamond window. The large Secondary Electron Yield (SEY) provides a multiplication of the number of electrons by about two orders of magnitude. The secondary electrons drift through the diamond under an electric field and emerge into the accelerating pro… more

Date: June 21, 2004

Creator: Rao, T.; Ben-Zvi, Ilan; Burrill, A.; Chang, X.; Hulbert, S.; Johnson, P. D. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Design Considerations for Low Field Short Photo-Injected Rf Electron Gun With High Charge Electron Bunch.

The RF field and space charge effect in a low field RF gun is given. The cell lengths are modified to have maximum accelerating efficiency. The modification introduces an extra RF field slice emittance. The phase space evolution of the following emittance compensation system is presented taking into account the chromatic effect. The emittance compensation mechanics for RF field and chromatic effect induced emittance is similar to that of compensating the space charge induced emittance. But the … more

Date: June 21, 2004

Creator: Chang, X.; Ben-Zvi, Ilan & Kewisch, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Simulated Performance of the Wisconsin Superconducting Electron Gun

The Wisconsin superconducting electron gun is modeled with multiparticle tracking simulations using the ASTRA and GPT codes. To specify the construction of the emittance-compensation solenoid, we studied the dependence of the output bunch's emittance upon the solenoid's strength and field errors. We also evaluated the dependence of the output bunch's emittance upon the bunch's initial emittance and the size of the laser spot on the photocathode. The results suggest that a 200-pC bunch with an e… more

Date: July 1, 2012

Creator: R.A. Bosch, K.J. Kleman, R.A. Legg

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Pressure Model for the Vacuum System for the Electron Gun and Injector for LCLS Final Design Report

The vacuum system of the injector for the Linac Coherent Light Source (LCLS) has been analyzed and configured by the Lawrence Livermore National Laboratory's New Technologies Engineering Division (NTED) as requested by the SLAC/LCLS program. The vacuum system layout and detailed analyses for the injector are presented in this final design report. The vacuum system was analyzed and optimized using a coupled gas load balance model of sub-volumes of the components to be evacuated.

Date: April 28, 2006

Creator: Tung, L S & Eriksson, L

Item Type: Report

Partner: UNT Libraries Government Documents Department

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The SLAC polarized electron source

The SLAC polarized electron source employs a photocathode DC high voltage gun with a loadlock and a YAG pumped Ti:sapphire laser system for colliding beam experiments or a flash lamp pumped Ti:sapphire laser for fixed target experiments. It uses a thin, strained GaAs(100) photocathode, and is capable of producing a pulsed beam with a polarization of {ge}80% and a peak current exceeding 10 A. Its operating efficiency has reached 99%. The physics and technology of producing high polarization elec… more

Date: June 1, 1995

Creator: Tang, H.; Alley, R. & Frisch, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Advanced photon source low-energy undulator test line

The injector system of the Advanced Photon Source (APS) consists of a linac capable of producing 450-MeV positrons or > 650-MeV electrons, a positron accumulator ring (PAR), and a booster synchrotron designed to accelerate particles to 7 GeV. There are long periods of time when these machines are not required for filling the main storage ring and instead can be used for synchrotron radiation research. We describe here an extension of the linac beam transport called the Low-Energy Undulator Test… more

Date: April 1, 1997

Creator: Milton, S. V.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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The Argonne Wakefield Accelerator: Upgrade scenarios and future experiments

The Argonne Wakefield Accelerator is presently operational and nearing completion of its initial dielectric structure- and plasma-based experimental program. In this paper a number of possible future improvements and directions for the AWA are discussed including photocathode source upgrades, laser pulse and beam shaping options, multiple drive bunch generation, and novel wakefield device measurements. Plans for a 1 GeV demonstration wakefield accelerator will be presented.

Date: October 1, 1997

Creator: Gai, W.; Conde, M.; Konecny, R.; Li, X.; Power, J.; Schoessow, P. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

A high-charge high-brightness L-band photocathode RF gun

The Argonne Wakefield Accelerator has been successfully commissioned and used for conducting wakefield experiments in dielectric loaded structures and plasmas. Although the initial wakefield experiments were successful, higher drive beam quality would substantially improve the wakefield accelerating gradients. In this paper the authors present a new 1-1/2 cell L-band photocathode RF gun design. This gun will produce 10--100 nC beam with 2--5 ps ms pulse length and normalized emittance less than… more

Date: February 25, 2000

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

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Experimental results of the ATF in-line injection system

The initial experimental results of the Brookhaven accelerator test facility (ATF) in-line injector is presented. The ATF in-line injector employed a full copper RF gun with a pair of solenoid magnets for emittance compensation. The maximum acceleration field of the RF gun was measured to be 130 MV/m. The electron yield from the copper cathode was maximized using p- polarized laser and the Schottky effect. The quantum efficiency under optimum conditions was measured to be 0.04%. The measured el… more

Date: May 1, 1995

Creator: Wang, X. J.; Srinivasan-Rao, T. & Batchelor, K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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The Argonne Wakefield Accelerator high current photocathode, gun and drive linac

The Argonne Wakefield Accelerator (AWA) is a new facility for advanced accelerator research. A major component of the AWA is its drive linac, consisting of a unique high current short pulse L-Band photocathode based gun and special standing wave preaccelerator designed to produce 100 nC, 30 ps electron bunches at 20 MeV. Commissioning on the drive linac is now underway. We report on our initial operating experience with this novel machine, including bunch length and emittance measurements.

Date: June 1, 1995

Creator: Schoessow, P.; Chojnacki, E. & Cox, G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

NLCTA injector experimental results

The purpose of the Next Linear Collider Test Accelerator (NLCTA) at SLAC is to integrate the new technologies of X-band accelerator structures and RF systems for the Next Linear Collider (NLC), demonstrate multibunch beam-loading energy compensation and suppression of high-order deflecting modes, measure the transverse components of the accelerating field, and measure the dark current generated by RF field emission in the accelerator. For beam loading R and D, an average current of about 1 A in… more

Date: April 1, 1997

Creator: Yeremian, A. D.; Adolphsen, C.; Miller, R. H.; Nantista, C. D. & Wang, J. W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Polarized Source Performance and Developments at Jefferson Lab

The polarized photoinjector at Jefferson Lab continues to provide high average current, high polarization, high quality beam to nuclear physics Users in as many as three endstations simultaneously. Long lifetime operation has been obtained from two identical polarized guns. A new high power mode locked Ti-sapphire laser has been constructed to enhance the effective operating lifetime of the photoinjector. Efforts to enhance beam polarization and reduced helicity correlated beam systematic effec… more

Date: October 1, 2000

Creator: Poelker, Matt; Adderley, P.; Clark, J.; Day, A.; Grames, Joseph; Hansknecht, J. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Structure and design of the electron lens for RHIC

Two electron lenses for a head-on beam-beam compensation are being planned for RHIC; one for each circulating proton beam. The transverse profile of the electron beam will be Gaussian up to a maximum radius of r{sub e} = 3{sigma}. Simulations and design of the electron gun with Gaussian radial emission current density profile and of the electron collector are presented. Ions of the residual gas generated in the interaction region by electron and proton beams will be removed by an axial gradient… more

Date: March 28, 2011

Creator: Pikin, A.; Fischer, W.; Alessi, J.; Anerella, M.; Beebe, E. Gassner, D.; Gu, X. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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An experiment to test the viability of a gallium-arsenide cathode in a SRF electron gun

Strained gallium arsenide cathodes are used in electron guns for the production of polarized electrons. In order to have a sufficient quantum efficiency lifetime of the cathode the vacuum in the gun must be 10{sup -11} Torr or better, so that the cathode is not destroyed by ion back bombardment or through contamination with residual gases. All successful polarized guns are DC guns, because such vacuum levels can not be obtained in normal conducting RF guns. A superconductive RF gun may provide … more

Date: May 4, 2009

Creator: Kewisch, J.; Ben-Zvi, Ilan; Rao, T.; Burrill, A.; Pate, D.; Wu, Q. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Accelerator and ff System Development for NLC

An experimental station for an X-band Next Linear Collider has been constructed at SLAC. This station consists of a klystron and modulator, a low-loss waveguide system for rf power distribution, a SLED II pulse-compression and peak-power multiplication system, acceleration sections and beam-line components (gun, prebuncher, preaccelerator, focussing elements and spectrometer). An extensive program of experiments to evaluate the performance of all components is underway. The station is described… more

Date: April 1, 1993

Creator: Vlieks, A. E.; Callin, R. & Deruyter, H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Circuit Model for Gun Driven Spheromaks

In this note we derive circuit equations for sustained spheromaks, in the phase after a spheromak is detached from the gun and sustained in a flux conserver. The impedance of the spheromak during the formation and ''bubble burst'' phase has been discussed by Barnes et. al. We assume here that the spheromak is formed and helicity is being delivered to it from the gun, currents are above the threshold current, and the {lambda}-gradients are outward ({lambda} decreasing inward). We follow an open … more

Date: July 14, 2000

Creator: Thomassen, K I

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Performance of the LBL AECR source at various frequencies

To study the effects of frequency on an electron cyclotron resonance (ECR) ion source, the LBL Advanced ECR ion source (designed to operate at 14 GHz) has been tested at 6.4, 10, and 14 GHz with one plasma chamber (ID = 6.0 cm), a permanent sextuple magnet (``closed sextuple``) with a field strength of 0.84 Tesla at the chamber wall, and no radial vacuum pumping. Pure oxygen was used as the running gas for a fair comparison. The source was tested as a single stage, as well as with cold electron… more

Date: July 1, 1992

Creator: Xie, Z. Q.; Lyneis, C. M.; Lundgren, S. A. & Collins, D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

RF Design of the LCLS Gun

Final dimensions for the LCLS RF gun are described. This gun, referred to as the LCLS gun, is a modified version of the UCLA/BNL/SLAC 1.6 cell S-Band RF gun [1], referred to as the prototype gun. The changes include a larger mode separation (15 MHz for the LCLS gun vs. 3.5 MHz for the prototype gun), a larger radius at the iris between the 2 cells, a reduced surface field on the curvature of the iris between the two cells, Z power coupling, increased cooling channels for operation at 120 Hz, du… more

Date: December 13, 2010

Creator: Limborg-Deprey, C

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

A high-DC-voltage GaAs photoemission gun: Transverse emittance and momentum spread measurements

We have built a high-DC-voltage photoemission gun and a diagnostic beamline permitting us to measure rms transverse emittance ({epsilon}{sub x}) and rms momentum spread ({delta}) of short-duration electron pulses produced by illuminating the cathode with light from a mode-locked, frequency-doubled Nd:YLF laser. The electron gun is a GaAs photocathode source designed to operate at 500kV. We have measured {epsilon}{sub x} and {delta} for conditions ranging from emittance-dominated to space-charge… more

Date: June 1, 1997

Creator: Engwall, D.; Bohn, C. & Cardman, L.

Item Type: Article

Partner: UNT Libraries Government Documents Department