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in subjects: "Beam Profiles"

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Beam measurements on Argonne linac for collider injector design

The 20 MeV electron linac at Argonne produces 5 x 10/sup 10/ electrons in a single bunch. This amount of charge per bunch is required for the proposed single pass collider at SLAC. For this reason the characteristics of the beam from this machine are of interest. The longitudinal charge distribution has been measured by a new technique. The technique is a variation on the deduction of bunch shape from a spectrum measurement. Under favorable conditions a resolution of about 1/sup 0/ of phase is … more

Date: July 1, 1980

Creator: James, M. B.; Koontz, R. F. & Miller, R. H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Brookhaven four-stage accel-decel production of low-energy highly stripped heavy ions

The dual MP tandem facility at Brookhaven has been used in a four-stage accel-decel mode to produce highly stripped S ion beams (Q = 10-16/sup +/). Fully stripped S ions were obtained at energies down to 8 MeV. The low energy limit is presently due to the inclined field configuration of the last acceleration tube.

Date: January 1, 1981

Creator: Barrette, J. & Thieberger, P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Duopigatron ion source studies

Ion source performance characteristics consisting of total ion current, ion energy distribution, mass distribution, and ion current density distribution were measured for several models of a duopigatron. Variations on the duopigatron design involved plasma expansion cup material and dimensions, secondary cathode material, and interelectrode spacings. Of the designs tested, the one with a copper and molybdenum secondary cathode and a mild steel plasma expansion cup proved to give the best result… more

Date: July 1, 1978

Creator: Bacon, F. M.; Bickes, R. W., Jr. & O'Hagan, J. B.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Optimization of compact synchrotron optics for x-ray lithography

The production of integrated circuits having sub-micron component dimensions has motivated the development of compact electron storage rings to provide synchrotron x-ray radiation. This paper presents considerations for optimizing the optics for small radius rings using superconducting dipole magnets. The key parameters are the sizes and angular divergences of the source points illuminating the different ports. Two ring designs are compared in terms of theoretical beam parameters achievable usi… more

Date: March 1, 1987

Creator: Decker, G.A. & Craft, B.C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Equivalent beam averaging (EBA) of I-V spectra for LEED analysis

An equivalent beam averaging (EBA) procedure is described which has proved to be very useful to enhance I-V profile data collected for LEED analyses. Specific analyses are documented where application of EBA has led to improved agreement between calculated and experimental I-V profiles. The procedure also has been substantiated by examination of representative I-V profiles which were calculated to correspond to the incident beam slightly misaligned from, and exactly aligned with, the surface no… more

Date: August 1, 1982

Creator: Davis, H. L. & Noonan, J. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Possible methods of measuring the length of sub-picosecond electron bunches in the frequency domain

The traditional method of measuring extremely short electron beams using streak cameras begins to become problematic and expensive at bunch lengths at a picosecond and below. In this paper a few alternatives, based on the differential measurement of the Fourier spectrum of the longitudinal charge distribution of a bunch are suggested and evaluated.

Date: December 1, 1992

Creator: Jackson, Gerald P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Determination of transverse phase-space and momentum error from size measurements along the 50-MeV H/sup -/ RCS injection line

The 50-MeV H/sup -/ injection line for the RCS at Argonne National Laboratory has 16 quadrupole and eight bending magnets. Horizontal and vertical profiles can be obtained at 12 wire scanner positions. Size information from these profiles can be used to determine the three ellipses parameters in each plane required to describe the transverse phase space. These locations that have dispersion permit the momentum error to be used as a fourth fitting parameter. The assumed accuracy of the size meas… more

Date: January 1, 1981

Creator: Cho, Y.; Crosbie, E.A. & Takeda, H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Low-emittance uniform density Cs sup + sources for heavy ion fusion accelerators studies

Low-emittance (high-brightness) Cs{sup +} thermionic sources were developed for the heavy ion induction linac experiment MBE-4 at LBL. The MBE-4 linac accelerates four 10 mA beams from 200 ke V to 900 ke V while amplifying the current up to a factor of nine. Recent studies of the transverse beam dynamics suggested that characteristics of the injector geometry were contributing to the normalized transverse emissions growth. Phase-space and current density distribution measurements of the beam ex… more

Date: April 1, 1991

Creator: Eylon, S.; Henestroza, E.; Garvey, T.; Johnson, R. & Chupp, W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Generation of a rectangular beam distribution for irradiation of the accelerator production of tritium target

A scheme has been developed to produce a well-confined rectangular beam-intensity distribution of greatly enhanced uniformity from initially-peaked intensity distributions such as Gaussian or parabolic distributions without beam scraping. This scheme employs a system of linear and nonlinear transport-line elements. The linear elements prepare the beam for the nonlinear focusing and govern the beam size at the target. Uniformity is achieved with octupoles, and beam confinement is assured with du… more

Date: January 1, 1990

Creator: Blind, B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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A calorimeter for measuring the neutral beam power reaching the plasma

A calorimeter has been designed to measure the neutral beam power reaching the Advanced Toroidal Facility (ATF) plasma. The high-heat-flux surface of this calorimeter is made of an array of graphite tiles. The calorimeter, which will be located in the adapter section between the ATF vacuum vessel and the beam line, is retractable so that it can be moved away from the plasma without opening the vacuum vessel during normal ATF operation. Two rows of thermocouples mounted perpendicular to each oth… more

Date: January 1, 1987

Creator: Menon, M. M.; Edmonds, P. H. & Hahs, C. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Transport and error sensitivity in a heavy-ion recirculator

An envelope code has been developed to facilitate the design of a recirculating accelerator for a heavy-ion fusion reactor. A novel feature of the model is the treatment of the beam charge density as a Lagrangian fluid in the axial direction. Transport results for a preliminary recirculator design are presented, and sensitivity of the transport to errors in the magnet strength is discussed. 4 refs., 4 figs.

Date: May 1, 1991

Creator: Sharp, W. M.; Barnard, J. J. & Yu, S. S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Energy and energy width measurement in the FNAL antiproton accumulator

The Fermilab Antiproton Accumulator has recently been used to produce Charmonium resonances (charm quark, anti-charm quark bound states) in proton-antiproton annihilations using an internal H{sub 2} gas jet target. A measurement of the resonance mass and width may be obtained from a precise knowledge of the antiproton beam energy and energy spread. The beam energy is measured to an accuracy of 1 part in 10{sup 4} in the range 6.3 Gev to 4.1 Gev by measuring the orbit length and revolution frequ… more

Date: October 1, 1991

Creator: Church, M.; Hsueh, S.; Rapidis, P. & Werkema, S.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Beam tomography in two and four dimensions. [100 MeV H/sup +/ beams and 750 keV H/sup -/ beams]

The coming generations of high beam-power accelerators require new techniques to monitor the emittance and the shape of the beam; in particular, measurements that do not interfere with the beam itself are necessary. A new computational algorithm, MENT (Maximum ENTropy), will be presented that combines nondestructive profile measurements taken from a number of stations along the beam line with beam-dynamics calculations to compute a four-dimensional phase-space distribution. A version of MENT ha… more

Date: January 1, 1979

Creator: Sander, O. R.; Minerbo, G. N.; Jameson, R. A. & Chamberlin, D. D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

An improved 8 GeV beam transport system for the Fermi National Accelerator Laboratory

A new 8 GeV beam transport system between the Booster and Main Ring synchrotrons at the Fermi National Accelerator Laboratory is presented. The system was developed in an effort to improve the transverse phase space area occupied by the proton beam upon injection into the Main Ring accelerator. Problems with the original system are described and general methods of beamline design are formulated. Errors in the transverse properties of a beamline at the injection point of the second synchrotron a… more

Date: June 1, 1987

Creator: Syphers, M.J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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(High energy physics)

This report discusses high energy physics research being conducted at the Stanford Linear Collider using the time projection chamber and the SLD detector.

Date: January 1, 1992

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Dependence of laser-plasma interaction physics on laser wavelength and plasma scalelength

We discuss the dependence of many features of laser-plasma interaction physics on both the laser wavelength and plasma dimensions. Experimental results that are presented include absorption, stimulated Brillouin scattering, suprathermal electron production, and optical signatures of the two plasmon decay and stimulated Raman instabilities. While the experiments show beneficial effects of decreasing laser wavelength on the coupling physics, the mix and efficiency of the various interaction proce… more

Date: April 9, 1984

Creator: Campbell, E. M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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The diagnostics system for the multiple heavy ion beams induction linac experiment, MBE-4

MBE-4 is a four beam current amplifying induction linac experiment conducted at LBL as a part of the Heavy Ion Fusion Accelerator Research (HIFAR) program for studying accelerator physics issues of a heavy ion driver for inertial fusion. The four ion beams (Cs{sup +}, 10 mA) are focused by electrostatic quadrupoles and accelerated fro about 200 keV to 900 keV through 24 induction gaps. Current amplification of up to nine times is achieved while the beam pulse duration is compressed from about 3… more

Date: September 1, 1991

Creator: Eylon, S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

A high resolution beam profile monitor using Bremsstrahlung

The development of efficient high energy linear colliders in the 1 TeV range requires final focus systems capable of producing beam spot sizes on the order of 1--20 nm, about three orders of magnitude smaller than those produced at the SLC. Although beam line designs exist which can, in principle, produce the required optics, the construction of quadrupoles with the size and precision required will be challenging. Field errors in these quads must be small and should be verified experimentally, … more

Date: January 1, 1988

Creator: Norem, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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ECH by FEL and gyrotron sources on the Microwave Tokamak Experiment (MTX) tokamak

The Microwave Tokamak Experiment (MTX) at LLNL is studying the physics of intense pulse ECH is a high-density tokamak plasma using a microwave FEL. Related technology development includes the FEL, a windowless quasi-optical transmission system, and other microwave components. Initial plasma experiments have been carried out at 140 GHz with single rf pulses generated using the ETA-II accelerator and the ELF wiggler. Peak power levels up to 0.2 GW and pulse durations up to 10 ns were achieved for… more

Date: August 9, 1990

Creator: Stallard, B. W.; Turner, W. C.; Allen, S. L.; Byers, J. A.; Felker, B.; Fenstermacher, M. E. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

(Study of electron-positron interactions at the Stanford Linear Accelerator Center)

This report briefly discusses experiments on the TPC and SLD projects dealing with electron-positron interactions. (LSP)

Date: January 1, 1991

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Motion control of the accumulator flying wires

Flying wire systems for the Fermilab Accumulator are being constructed in order to measure the transverse beam profiles during stacking. Each device passes a 25 micron carbon filament through the beam transversely at a constant velocity of 10 m/s. Collisions between the beam particles and the wire produce secondary particle cascades, which in turn produce photons in a scintillator. A photomultiplier tube is used to measure the light intensity while the wire position is determined by an optical … more

Date: April 23, 1990

Creator: Wang, X.Q.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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The BNL Accelerator Test Facility and experimental program

The Accelerator Test Facility (ATF) at BNL is a users' facility for experiments in Accelerator and Beam Physics. The ATF provides high brightness electron beams and high-power laser pulses synchronized to the electron beam, suitable for studies of new methods of high-gradient acceleration and state-of-the-art Free-Electron Lasers. The electrons are produced by a laser photocathode rf gun and accelerated to 50 MeV by two traveling wave accelerator sections. The lasers include a 10 mJ, 10 ps ND:Y… more

Date: January 1, 1992

Creator: Ben-Zvi, Ilan

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

3-D numerical analysis of a high-gain free-electron laser

We present a novel approach to the 3-dimensional high-gain free- electron laser amplifier problem. The method allows us to write the laser field as an integral equation which can be efficiently and accurately evaluated on a small computer. The model is general enough to allow the inclusion of various initial electron beam distributions to study the gain reduction mechanism and its dependence on the physical parameters. 16 refs., 8 figs., 1 tab.

Date: October 19, 1988

Creator: Gallardo, J.C.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Polarized Deuteron Target in an Electron Storage Ring: Measurements and Perspectives

A gas jet of polarized deuterium atoms with a thickness of 2 /times/ 10 cm/sup /minus/2/ has been used as an internal target in the VEPP-3 electron storage ring with 2 GeV energy. Source characteristics as well as experimental conditions and results on elastic and inelastic scattering are reviewed. Results of experimental studies and calculations of jet depolarization induced by an electron beam are discussed. For the first time a storage cell for polarized atoms was used in the storage ring in… more

Date: January 1, 1988

Creator: Mishnev, S. I.; Nikolenko, D. M.; Popov, S. G.; Rachek, I. A.; Temnykh, A. B.; Toporkov, D. K. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department