In-Situ Cleaning of Metal Photo-Cathodes in rf Guns
Metal cathodes installed in rf guns typically exhibit much lower quantum efficiency than the theoretical limit. Experimenters often use some sort of in situ technique to ''clean'' the cathode to improve the QE. The most common technique is laser cleaning where the laser is focused to a small spot and scanned across the cathode surface. However, since the laser is operated near the damage threshold, it can also damage the cathode and increase the dark current. The QE also degrades over days and must be cleaned regularly. We are searching for a more robust cleaning technique that cleans the entire cathode surface simultaneously. In this paper we describe initial results using multiple techniques such as several keV ion beams, glow discharge cleaning and back bombarding electrons. Results are quantified in terms of the change in QE and dark current.
- Research Organization:
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC02-76SF00515
- OSTI ID:
- 896939
- Report Number(s):
- SLAC-PUB-12206; TRN: US200705%%15
- Resource Relation:
- Conference: Presented at 28th International Free Electron Laser Conference (FEL 2006), Berlin, Germany, 27 Aug - 1 Sep 2006
- Country of Publication:
- United States
- Language:
- English
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