Study on a long-life photocathode with an CsBr protective layer for an rf electron gun

Hiroya Ono, Junya Miyamatsu, Tomoaki Tamba, Kazuyuki Sakaue*, Masakazu Washio, Hokuto Iijima, Heishun Zen

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


A photocathode with a high quantum efficiency (Q.E.) and long lifetime can be fabricated by evaporating a protective layer onto a high Q.E. semiconductor photocathode. In this study we tried to improve the stability and lifetime of a Cs-Te photocathode by coating a CsBr protective layer of 20 nm in thickness over the surface. After the protective layer was applied, we measured the Q.E. of the photocathode and the lifetime in the evaporation chamber. The Q.E. of the coated Cs-Te was confirmed to be about 0.80% and to remain unchanged for a period of longer than 25 d. The effectiveness of the protective layer against exposure of the Cs-Te photocathode to oxygen gas was also confirmed for the first time. Our experiments were the first to show a lifetime improvement of a photocathode installed inside an rf gun compared to the same type of photocathode with no protective coating.

Original languageEnglish
Article number066005
JournalJapanese journal of applied physics
Issue number6
Publication statusPublished - 2019

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)


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