Because of the high Q.E. in visible light range and the best performance as a polarized electron source, GaAs photocathodes are used worldwide in DC photoguns for large accelerator facilities. The preparation and operation of GaAs(Cs, O) is very demanding, for instance an ultra high vacuum of 10-11 mbar is required. For this reason, a new preparation chamber and transfer system is developed at HZDR.
R. Xiang, et al., Polarized Sources, Targets & Polarimetry, published by World Scientific, p249
R. Xiang, et al., Research Activities on Photocathodes for HZDR SRF Gun. Proceedings of IPAC 2012