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Title: Laser Electron Gamma Source. Biennial progress report

The LEGS facility provides intense, polarized, monochromatic {gamma}-ray beams by Compton backscattering laser light from relativistic electrons circulating in the X-Ray storage ring of the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory. With the start of ring operations at 2.8 GeV, LEGS {gamma}-ray energies now extend to 370 MeV. Considerable progress has been made in the development of a new laser system that will increase the beam energies to 470 MeV, and this system is expected to come into operation before the next biennial report. The total flux is administratively held at 6 {times} 10{sup 6} s{sup {minus}1}. The {gamma}-ray energy is determined, with a resolution of 5.5 MeV, by detecting the scattering electrons in a magnetic spectrometer. This spectrometer can `tag` all {gamma}-rays with energies from 185 MeV up to the Compton edge. The beam spot size at the target position is 8 mm (V) {times} 18 mm (H), FWHM. For a single laser wavelength, the linear polarization of the beam is 98% at the Compton edge and decreases to 50% at about 1/2 the energy of the edge. By choosing the laser wavelengths appropriately the polarization can be maintained above 85% throughout the tagging range. Duringmore » the last two years, experimental running at LEGS occupied an average of 3000 hours annually. Highlights of some of the programs are discussed below.« less
Authors:
 [1] ; ; ; ; ; ;  [2] ;  [3] ;  [4]
  1. ed.
  2. Brookhaven National Lab., Upton, NY (United States)
  3. Univ. of Virginia, Charlottesville, VA (United States). Dept. of Physics
  4. Brookhaven National Lab., Upton, NY (United States)|[Virginia Polytechnic Institute & State Univ., Blacksburg, VA (United States). Dept. of Physics
Publication Date:
OSTI Identifier:
10179224
Report Number(s):
BNL--60698
ON: DE94017815; TRN: 94:016725
DOE Contract Number:
AC02-76CH00016
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: Jun 1994
Research Org:
Brookhaven National Lab., Upton, NY (United States)
Sponsoring Org:
USDOE, Washington, DC (United States)
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; GAMMA SOURCES; POLARIZATION; RADIATION FLUX; PROGRESS REPORT; NSLS; LASER RADIATION; COMPTON EFFECT 430303; EXPERIMENTAL FACILITIES AND EQUIPMENT