Effects of atomic hydrogen and deuterium exposure on high polarization GaAs photocathodes
Journal Article
·
· Physical Review Special Topics. Accelerators and Beams
Strained-layer GaAs and strained-superlattice GaAs photocathodes are used at Jefferson Laboratory to create high average current beams of highly spin-polarized electrons. High electron yield, or quantum efficiency (QE), is obtained only when the photocathode surface is atomically clean. For years, exposure to atomic hydrogen or deuterium has been the photocathode cleaning technique employed at Jefferson Laboratory. This work demonstrates that atomic hydrogen cleaning is not necessary when precautions are taken to ensure that clean photocathode material from the vendor is not inadvertently dirtied while samples are prepared for installation inside photoemission guns. Moreover, this work demonstrates that QE and beam polarization can be significantly reduced when clean high-polarization photocathode material is exposed to atomic hydrogen from an rf dissociator-style atomic hydrogen source. Surface analysis provides some insight into the mechanisms that degrade QE and polarization due to atomic hydrogen cleaning.
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA
- Sponsoring Organization:
- USDOE - Office of Energy Research (ER)
- DOE Contract Number:
- AC05-84ER40150
- OSTI ID:
- 876536
- Report Number(s):
- JLAB-ACC-05-401; DOE/ER/40150-3777
- Journal Information:
- Physical Review Special Topics. Accelerators and Beams, Journal Name: Physical Review Special Topics. Accelerators and Beams Journal Issue: 12 Vol. 8; ISSN 1098-4402
- Country of Publication:
- United States
- Language:
- English
Similar Records
GaAs-based superlattice photocathodes manufactured using MOCVD provide spin polarization > 90% and quantum efficiency > 1%
Effect of Atomic Hydrogen Exposure on Electron Beam Polarization from Strained GaAs photocathodes
Effect of Atomic Hydrogen Exposure on Electron Beam Polarization from Strained GaAs photocathodes
Conference
·
Tue Feb 28 23:00:00 EST 2023
·
OSTI ID:2282043
Effect of Atomic Hydrogen Exposure on Electron Beam Polarization from Strained GaAs photocathodes
Conference
·
Tue Jul 01 00:00:00 EDT 2003
·
OSTI ID:837594
Effect of Atomic Hydrogen Exposure on Electron Beam Polarization from Strained GaAs photocathodes
Conference
·
Tue Jul 01 00:00:00 EDT 2003
·
OSTI ID:837593