原文传递 DC photogun vacuum characterization through photocathode lifetime studies
题名: DC photogun vacuum characterization through photocathode lifetime studies
作者: Philip Adderley;Kenneth Surles-Law;Matt Poelker;Joseph Grames;Marcy Stutzman;
关键词: 43 PARTICLE ACCELERATORS; CEBAF ACCELERATOR; COATINGS; DESIGN; ELECTRON GUNS; IONIZATION; LIFETIME; PHOTOCATHODES; PRESSURE MEASUREMENT; VACUUM SYSTEMS
摘要: Excellent vacuum is essential for long photocathode lifetimes in DC high voltage photoelectron guns. Vacuum Research at Thomas Jefferson National Accelerator Facility has focused on characterizing the existing vacuum systems at the CEBAF polarized photoinjector and on quantifying improvements for new systems. Vacuum chamber preprocessing, full activation of NEG pumps and NEG coating the chamber walls should improve the vacuum within the electron gun, however, pressure measurement is difficult at pressures approaching the extreme-high-vacuum (XHV) region and extractor gauge readings are not significantly different between the improved and original systems. The ultimate test of vacuum in a DC high voltage photogun is the photocathode lifetime, which is limited by the ionization and back-bombardment of residual gasses. Discussion will include our new load-locked gun design as well as lifetime measurements in both our operational and new photo-guns, and the correlations between measured vacuum and lifetimes will be investigated.
报告类型: 科技报告
检索历史
应用推荐