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in subjects: "Beam Bunchers"

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Operating experience with the ALS linac

The linac injector for the Advanced Light Source (ALS) at LBL was recently put into operation. Energy is 50 MeV, frequency 3 GHz. The electron gun delivers up to 6nC in a 3.0-ns bunch at 120 kV. A train of bunches is injected into a 1-Hz booster and accelerated to 1.5 GHz for storage ring injection. A magnetic analysis system is used for optimizing the linac. Measured beam properties from the gun and after acceleration in the linac are described. 9 refs., 3 figs.

Date: May 1, 1991

Creator: Selph, F. & Massoletti, D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

New newtron time-of-flight (NTOF) facilities at the Brookhaven 200-MeV Linac

The installation of a new beam chopper and radio-frequency quadrupole (RFQ) preinjector (750 keV) at the Brookhaven National Laboratory (BNL) 200-MeV Linac will enable single micropulse selection (pulse width <1 ns) with periods ranging from 400 ns to 10 ..mu..s. The standard micropulse intensity is 1.2 X 10/sup 9/ p..mu.. pulse with dc-average beam currents of 50 nA-1 ..mu..A routinely available. The NTOF facilities consists of 30-100 meter flight paths at angles of 0, 12, 30, 45, 90, and 135/… more

Date: January 1, 1988

Creator: Ward, T.E.; Alessi, J.; Brennan, J.; Grand, P.; Lankshear, R.; Snead, C.L. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

New high-brightness electron injector for free-electron lasers driven by rf linacs

A free-electron laser oscillator, driven by an rf linac, requires a train of electron bunches delivered to an undulator. The brightness requirement exceeds that available from a conventional linac with rf bunchers. The demonstrated high brightness of laser-illuminated photoemitters indicates that the conventional buncher system might be eliminated entirely, thereby avoiding the usual loarge loss in brightness that occurs in bunchers. A photoemitter with a current density of about 200 A/cm/sup 2… more

Date: January 1, 1985

Creator: Fraser, J.S.; Sheffield, R.L. & Gray, E.R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Beam parametr measurements for the SLAC linear collider

A stable, closely-controlled, high-intensity, single-bunch beam will be required for the SLAC Linear Collider. The characteristics of short-pulse, low-intensity beams in the SLAC linac have been studied. A new, high-intensity thermionic gun, subharmonic buncher and S-band buncher/accelerator section were installed recently at SLAC. With these components, up to 10/sup 11/ electrons in a single S-band bunch are available for injection into the linac. the first 100-m accelerator sector has been mo… more

Date: January 1, 1981

Creator: Clendenin, J. E.; Blocker, C. & Breidenbach, M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Misalignment study of NLC bunch compressor

Results of computer simulations of the misalignments in the 180{degree}-bend angle second-stage bunch compressor for the NLC are described. The aim of this study was to evaluate alignment and production error tolerances. Three versions of the second stage, differing in their minimum obtainable bunch length (44 {mu}, 60 {mu}, and 86 {mu}) were studied. Simulations included orbit correction produced by errors and misalignments of the compressor elements. The orbit correction itself was done withi… more

Date: May 1, 1991

Creator: Rogers, R.P. & Kheifets, S.A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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H sup minus beam characterization using laser-induced neutralization

The Laser-induced neutralization techniques, LINDA, is important as a noninterceptive diagnostic for quantitatively measuring beam emittance values. It is also valuable for its capability to characterize, both quantitatively and qualitatively, the performance and match of linac components. In this paper we present LINDA experimental results that show how the output beam of a radio-frequency quadrupole (RFQ) and drift-tube linac (DTL) combination changes with the variation of RFQ-DTL relative ph… more

Date: January 1, 1991

Creator: Yuan, V. W.; Garcia, R.; Johnson, K. F.; Saadatmand, K.; Sander, O. R.; Sandoval, D. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Advanced Light Source Linac subharmonic buncher cavities

The Linear Accelerator (Linac) in the Advanced Light Source (ALS) is designed to provide either single or multiple bunches of 50 MeV electrons for the booster synchrotron. Three bunchers are used in the Linac. The 3 GHz S band buncher has been described elsewhere. This report deals with the two lower subharmonic bunchers. One operates at 124.914 MHz while the other operates at 499.654 MHz. 12 refs., 2 figs.

Date: March 1, 1989

Creator: Lo, C.C.; Taylor, B.; Lancaster, H. & Guigli, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Pulse compression system for the ANL 20 MeV linac

This paper describes the pulse compression system being built on the Argonne 20 MeV electron linac. The system is designed to rotate the bunch from the present measured pulse length of 38 psec FWHM, to pulse lengths of 5 to 6 ps with the large instantaneous currents (1 to 4 kA) possible instantaneous current. This system was necessary to extend the study of reactive fragments of molecules to the time scale of a few picoseconds, in particular to examine the chemistry of electrons and ions before… more

Date: January 1, 1986

Creator: Mavrogenes, G.; Norem, J. & Simpson, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Improving the performance of power-limited transverse stochastic cooling systems

We present the formulas relevant to the behavior of (transverse) stochastic cooling systems which operate under the not uncommon condition that performance is limited by available output power, and contrast the operation of such systems with non-power-limited ones. In particular, we show that for power-limited systems, the two most effective improvements are the use of pickups/kickers which operate in both planes simultaneously and/or plunging of the cooling system electrodes, and present an ex… more

Date: August 1, 1989

Creator: Goldberg, D.A. & Lambertson, G.R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The numerical simulation of accelerator components

The techniques of the numerical simulation of plasmas can be readily applied to problems in accelerator physics. Because the problems usually involve a single component ''plasma,'' and times that are at most, a few plasma oscillation periods, it is frequently possible to make very good simulations with relatively modest computation resources. We will discuss the methods and illustrate them with several examples. One of the more powerful techniques of understanding the motion of charged particle… more

Date: May 1, 1987

Creator: Herrmannsfeldt, W.B. & Hanerfeld, H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Racetrack microtron rf system

The rf system for the National Bureau of Standards (NBS)/Los Alamos cw racetrack microtron is described. The low-power portion consists of five 75-W amplifers that drive two input ports in each of two chopper deflection cavities and one port in the prebuncher cavity. A single 500-kW klystron drives four separate 2380-MHz cavity sections: the two main accelerator sections, a capture section, and a preaccelerator section. The phases and amplitudes in all cavities are controlled by electronic or e… more

Date: January 1, 1985

Creator: Tallerico, P.J. & Keffeler, D.R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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MEQALAC rf accelerating structure

A prototype MEQALAC capable of replacing the Cockcroft Walton pre-injector at BNL is being fabricated. Ten milliamperes of H/sup -/ beam supplied from a source sitting at a potential of -40 kilovolt is to be accelerated to 750 keV. This energy gain is provided by a 200 Megahertz accelerating system rather than the normal dc acceleration. Substantial size and cost reduction would be realized by such a system over conventional pre-accelerator systems.

Date: January 1, 1981

Creator: Keane, J. & Brodowski, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Rf deflector-chopper for SSC (Superconducting Super Collider) injector

In a proposed SSC linac injector the Low-Energy Booster lattice painting scheme requires a 50-MHz microbunch structure with transverse and longitudinal normalized rms emittances of less than 0.45 /pi/-mm-mrad and 1.7 /times/ 10/sup /minus/5/ /pi//center dot/eV/center dot/s, respectively, at 600 MeV. A 50-MHz RFQ design does not meet the longitudinal emittance requirements; a 150-MHz RFQ can do so, but requires a chopping scheme that produces a clean 50-MHz beam structure without degrading emitt… more

Date: January 1, 1989

Creator: Guy, F. W. & Bhatia, T. S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Generation and acceleration of high intensity beams in the SLC injector

A new gun pulser and substantially increased focusing have been added to the first 100 m of the SLAC linac in order to provide a pair of intense electron bunches to the SLC damping ring. Each bunch from this injector must have 5 x 10/sup 10/ electrons, an invariant emittance ..gamma..epsilon less than or equal to 1.8 x 10/sup -3/ m-rad and the pair must have an energy spread of less than 2%. Wakefield instabilities present in earlier versions of this injector have been controlled by reducing th… more

Date: April 1, 1985

Creator: Ross, M. C.; Browne, M. J.; Clendenin, J. E.; Jobe, R. K.; Seeman, J. T.; Sheppard, J. C. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Phase and amplitude feedback control system for the Los Alamos free-electron laser

Phase and amplitude feedback control systems for the Los Alamos free-electron laser (FEL) are described. Beam-driven voltages are very high in the buncher cavity because the electron gun is pulsed at the fifth subharmonic of the buncher resonant frequency. The high beam loading necessitated a novel feedback and drive configuration for the buncher. A compensation cirucit has been added to the gun/driver system to reduce observed drift. Extremely small variations in the accelerator gradients had … more

Date: January 1, 1985

Creator: Lynch, M. T.; Tallerico, P. J. & Higgins, E. F.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Los Alamos high-current proton storage ring: a status report

The Proton Storage Ring (PSR), whose installation was recently completed at Los Alamos, is a fast-cycling high-current accumulator designed to produce intense 800 MeV proton pulses for driving a spallation neutron source. The ring converts long beam pulses from the LAMPF linear accelerator into short bunches well matched to requirements of a high-resolution neutron-scattering materials science program. The initial performance goal for this program is to provide 100-..mu..A average current at th… more

Date: January 1, 1985

Creator: Lawrence, G. P.; Hardekopf, R. A.; Jason, A. J.; Clout, P. N. & Sawyer, G. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Rf power system for the chopper/buncher system on the NBS-Los Alamos RTM

The rf power system and its closed-loop feedback control for the racetrack microtron (RTM) chopper/buncher system are described. Measurements made on the response of the feedback system to external perturbations will also be reported.

Date: January 1, 1985

Creator: Young, L. M. & Keffeler, D. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Microbunching Instability in a Chicane: Two-Dimensional Mean Field Treatment

We study the microbunching instability in a bunch compressor by a parallel code with some improved numerical algorithms. The two-dimensional charge/current distribution is represented by a Fourier series, with coefficients determined through Monte Carlo sampling over an ensemble of tracked points. This gives a globally smooth distribution with low noise. The field equations are solved accurately in the lab frame using retarded potentials and a novel choice of integration variables that eliminat… more

Date: January 27, 2009

Creator: Bassi, G.; Ellison, James A.; Heinemann, Klaus & Warnock, Robert

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Matching the BtA line to the bare-AGS (Part 1)

The Booster to AGS (BtA) transfer line [Ref for BtA line] transports the beam bunches from the AGS-Booster to the AGS synchrotron, and also matches the beam parameters ({beta}{sub x,y}, {alpha}{sub x,y}) and dispersion functions ({eta}{sub x,y}, {eta}{prime}{sub x,y}) of the transported beam to the corresponding quantities of the circulating beam in AGS, at the AGS injection point. In this technical note we describe in details, the calculations of the matching procedure of the BtA line to the b… more

Date: November 1, 2008

Creator: Tsoupas, N.; Glenn, J. W.; Huan, H.; MacKay, W. W.; Raparia, D. & Zeno, K.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Control system for the Holifield Heavy Ion Research Facility beam buncher

A beam buncher has been developed to produce very short pulses of beam from the 25 MV accelerator for injection into ORIC. The buncher is a two-harmonic double-drift klystron-type operating over a frequency range of 4.5 to 14.5 MHz and has produced 1.1-ns pulse widths of /sup 16/O in tests on the ORNL EN tandem accelerator. Both rf voltage on, and relative phase between, the two buncher drift tubes must be accurately controlled to maintain the required narrow pulse width. A control system has b… more

Date: January 1, 1979

Creator: Ziegler, N.F.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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A fast chopper for programmed population of the longitudinal phase space of the AGS

A fast beam chopper has been built that can produce an arbitrary pulse program of the 200 MeV H/sup /minus// beam for synchronous injection into moving rf buckets in the AGS. The chopper will eliminate rf capture losses and can be used to tailor the initial distribution in longitudinal phase space by varying the pulse parameters, width and phase, on a bunch-by-bunch time scale, during multi-turn injection. The chopper also serves as a studies tool since it can provide controllable beam intensit… more

Date: January 1, 1989

Creator: Brennan, J. M.; Ahrens, L.; Alessi, J.; Brodowski, J.; Kats, J. & van Asselt, W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Application of the rf quadrupole in linear accelerators for heavy ion fusion

The rf quadrupole (RFQ) linac structure is proposed as an alternative to a system composed of a buncher and independently phased cavities in the low-velocity acceleration section. Beam dynamics simulation studies have demonstrated that with the RFQ (1) high transmission and low beam loss are possible, (2) it is possible to use a low voltage 0.25 MV dc injector and still obtain high output beam currents, (3) the current required from the injector is reduced because of the high transmission of th… more

Date: January 1, 1979

Creator: Wangler, T. P. & Stokes, R. H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Mechanical technologies for PIGMI. [Pion Generator for Medical Irradiations]

PIGMI (Pion Generator for Medical Irradiations) is a compact linear proton accelerator designed for a hospital environment. The prototype of the low energy section of PIGMI has been designed and is being fabricated at the Los Alamos Scientific Laboratory. It is an accelerator design which makes use of several advanced or innovative technologies. The PIGMI Prototype consists of a 250 keV injector, a double harmonic buncher, a tape-wound 13 KG solenoid magnet, and four accelerator tanks with a to… more

Date: January 1, 1979

Creator: Hansborough, L.D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Double-drift beam bunching systems

The double-drift beam bunching system consists of two bunchers that are separated in space, independently driven but phase-locked together. The second buncher to be encountered by the beam is driven at twice the frequency of the first. This system offers an attractive alternative to conventional one- and two-frequency systems since its bunching efficiency is about twice that for a single frequency system and about 25% larger than that for a two-frequency system in which both harmonics are impos… more

Date: January 1, 1978

Creator: Milner, W. T.

Item Type: Article

Partner: UNT Libraries Government Documents Department