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Title: Utilization of optical image data from the Advanced Test Accelerator (ATA)

Abstract

Extensive use is made of optical diagnostics to obtain information on the 50-MeV, 10-kA, 70-ns pulsed-electron beam produced by the Advanced Test Accelerator (ATA). Light is generated by the beam striking a foil inserted in the beamline or through excitation of the gas when the beamline is filled with air. The emitted light is collected and digitized. Two-dimensional images are recorded by either a gated framing camera or a streak camera. Extraction of relevant beam parameters, such as current density, current, and beam size, requires an understanding of the physics of the light-generation mechanism and an ability to handle and properly exploit a large digital database of image data. We will present a brief overview of the present understanding of the light-generation mechanisms in foil and gas, with emphasis on experimental observations and trends. We will review our data management and analysis techniques and indicate successful approaches for extracting beam parameters.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab., CA (USA)
OSTI Identifier:
6506074
Report Number(s):
UCRL-95366; CONF-870584-3
ON: DE87009573
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Conference
Resource Relation:
Conference: SPIE technical symposium on optics and optoelectronics, Orlando, FL, USA, 15 May 1987; Other Information: Portions of this document are illegible in microfiche products
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ELECTRON BEAMS; IMAGE PROCESSING; CALIBRATION; DATA ACQUISITION; DATA ANALYSIS; RECORDING SYSTEMS; STREAK CAMERAS; BEAMS; CAMERAS; LEPTON BEAMS; MEASURING INSTRUMENTS; PARTICLE BEAMS; PROCESSING; RADIATION DETECTORS; 430200* - Particle Accelerators- Beam Dynamics, Field Calculations, & Ion Optics

Citation Formats

Chambers, F.W., Kallman, J.S., Slominski, M.E., Chong, Y.P., Donnelly, D., and Cornish, J.P.. Utilization of optical image data from the Advanced Test Accelerator (ATA). United States: N. p., 1987. Web.
Chambers, F.W., Kallman, J.S., Slominski, M.E., Chong, Y.P., Donnelly, D., & Cornish, J.P.. Utilization of optical image data from the Advanced Test Accelerator (ATA). United States.
Chambers, F.W., Kallman, J.S., Slominski, M.E., Chong, Y.P., Donnelly, D., and Cornish, J.P.. 1987. "Utilization of optical image data from the Advanced Test Accelerator (ATA)". United States. doi:. https://www.osti.gov/servlets/purl/6506074.
@article{osti_6506074,
title = {Utilization of optical image data from the Advanced Test Accelerator (ATA)},
author = {Chambers, F.W. and Kallman, J.S. and Slominski, M.E. and Chong, Y.P. and Donnelly, D. and Cornish, J.P.},
abstractNote = {Extensive use is made of optical diagnostics to obtain information on the 50-MeV, 10-kA, 70-ns pulsed-electron beam produced by the Advanced Test Accelerator (ATA). Light is generated by the beam striking a foil inserted in the beamline or through excitation of the gas when the beamline is filled with air. The emitted light is collected and digitized. Two-dimensional images are recorded by either a gated framing camera or a streak camera. Extraction of relevant beam parameters, such as current density, current, and beam size, requires an understanding of the physics of the light-generation mechanism and an ability to handle and properly exploit a large digital database of image data. We will present a brief overview of the present understanding of the light-generation mechanisms in foil and gas, with emphasis on experimental observations and trends. We will review our data management and analysis techniques and indicate successful approaches for extracting beam parameters.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1987,
month = 1
}

Conference:
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  • Optical data showing emittance growth through the Advanced Test Accelerator (ATA) beam pulse have been obtained using a new beam profile diagnostic, Cerenkov radiation emitted from a quartz foil inserted into the path of the electron beam. This diagnostic gave extremely bright optical emissions which allowed productive operation of a streak camera in addition to the gated 2-D image-intensified CCD TV cameras previously used. Measurements were made at cells 15 (/approximately/3.75 MeV), cell 90 (/approximately/22.5 MeV) and 11 m beyond the accelerator (/approximately/43 MeV). In particular, it was possible to measure beam profiles inside the ion channel where the beammore » was so tightly pinched that the current density exceeded the damage threshold of previous foils (titanium and kapton). Double-Gaussian fits to the transverse beam profile were often found to be better than a single Gaussian fit. Two-component beams were observed for the 3-kA case at cell 15 and for the 1-, 3-, and 7-kA cases at 11 m. At cell 15, the large-beam component carried an increasing fraction of beam current starting from the middle of the pulse. 13 figs.« less
  • Beam current density profiles of ATA have been measured both spatially and temporally using a number of diagnostics. An extremely important technique involves measuring optical emissions from either a target foil inserted into the beam path or gas atoms and molecules excited by beam electrons. This paper describes the detection of the optical emission. A 2-D gated television camera with a single or dual micro-channel-plate (MCP) detector for high gain provides excellent spatial and temporal resolution. Measurements are routinely made with resolutions of 1 mm and 5 ns respectively. The optical line of sight allows splitting part of the signalmore » to a streak camera or photometer for even higher time resolution.« less
  • The ATA is a 50-MeV, 10-kA, 70-ns pulsed electron beam accelerator that generates an extremely harsh environment for diagnostic measurements. Diagnostic targets placed in the beamline are subject to damage, frequently being destroyed by a single pulse. High radiation (x-ray, gamma, and neutron) and electromagnetic interference levels preclude placing components near the beamline that are susceptible to radiation damage. Examples of such components are integrated circuit elements, hydrocarbons such as Teflon insulation, and optical components that darken, resulting in transmission loss. Optical diagnostics play an important part in measuring experimental parameters such as the beam current density profile. A largemore » number of optical lines of sight (LOS) are routinely deployed along the experimental beamlines that use the ATA beam. Gated TV cameras are located outside the accelerator tunnel, because the tunnel is inaccessible during operations. We will describe and discuss the difficulties, problems, and solutions encountered in making optical measurements in the ATA environment.« less
  • PALADIN is a 10.6-..mu..m FEL amplifier experiment operating at the Lawrence Livermore National Laboratory's Advanced Test Accelerator, an induction linear accelerator designed to produce a 45-MeV, 10-kA electron beam. With a 15-m long wiggler, PALADIN demonstrated 27 dB of exponential gain from a 14-kW input signal. With a 5-MW input signal, the amplifier saturated after 10 dB of gain. The exponentially growing signal in the unsaturated amplifier was clearly seen to be gain guided by the electron beam. 7 refs., 8 figs.
  • The AATF has been used to study wakefield acceleration and focusing in plasmas and rf structures. A PC-based system is described which incorporates the functions of beamline control and acquisition, storage, and preliminary analysis of video images from luminescent screen beam diagnostics. General features of the offline analysis of wakefield data are also discussed. 4 refs., 3 figs.