A low-voltage retarding-field Mott polarimeter for photocathode characterization

J. L. McCarter, M. L. Stutzman, Kenneth W Trantham, T. G. Anderson, A. M. Cook, T. J. Gay

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Nuclear physics experiments at Thomas Jefferson National Accelerator Facility's CEBAF rely on high polarization electron beams. We describe a recently commissioned system for prequalifying and studying photocathodes for CEBAF with a load-locked, low-voltage polarized electron source coupled to a compact retarding-field Mott polarimeter. The polarimeter uses simplified electrode structures and operates from 5 to 30kV. The effective Sherman function for this device has been calibrated by comparison with the CEBAF 5 MeV Mott polarimeter. For elastic scattering from a thick gold target at 20keV, the effective Sherman function is 0.201(5). Its maximum efficiency at 20keV, defined as the detected count rate divided by the incident particle current, is 5.4(2) × 10-4, yielding a figure-of-merit, or analyzing power squared times efficiency, of 1.0(1) × 10-5. The operating parameters of this new polarimeter design are compared to previously published data for other compact Mott polarimeters of the retarding-field type.

Original languageEnglish (US)
Pages (from-to)30-36
Number of pages7
JournalNuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Volume618
Issue number1-3
DOIs
StatePublished - Jun 1 2010

Fingerprint

Photocathodes
Polarimeters
photocathodes
polarimeters
low voltage
retarding
Electric potential
Electron sources
Nuclear physics
Elastic scattering
electron sources
nuclear physics
figure of merit
Particle accelerators
Electron beams
elastic scattering
accelerators
Gold
electron beams
Polarization

Keywords

  • Mott
  • Polarimeter
  • Polarization
  • Source

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Instrumentation

Cite this

A low-voltage retarding-field Mott polarimeter for photocathode characterization. / McCarter, J. L.; Stutzman, M. L.; Trantham, Kenneth W; Anderson, T. G.; Cook, A. M.; Gay, T. J.

In: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 618, No. 1-3, 01.06.2010, p. 30-36.

Research output: Contribution to journalArticle

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