Performance of GAASP/GAAS Superlattice Photocathodes in High Energy Experiments Using Polarized Electrons

摘要

The GaAsP/GaAs strained superlattice photocathode structure has proven to be a significant advance for polarized electron sources operating with high peak current per microbunch and relatively low duty factor. This is the characteristic type of operation of SLAC and is also planned for the ILC. This superlattice structure was studied at SLAC, and an optimum variation was chosen for the final stage of E-158, a high-energy parity violating experiment at SLAC. Following E-158, the polarized source was maintained on standby with the cathode being re-cesiated about once a week while a thermionic gun, which is installed in parallel with the polarized gun, supplied the linac electron beams.