Orlov, D. A., Krantz, C., Wolf, A., Jaroshevich, A. S., Kosolobov, S. N., Scheibler, H. E., et al. (2009). Long term operation of high quantum efficiency GaAs(Cs,O) photocathodes using multiple recleaning by atomic hydrogen. Journal of Applied Physics, 106: 054907, pp. 1-7. doi:10.1063/1.3208054.