On-line measurement system of GaAs photocathodes and its applications

摘要: The preparation process of GaAs photocathodes is very complicated, in order to prepare the high performance cathodes, it crucial obtain information enough evaluate real time. Based on a particular transfer light setup and flexible communication network, we develop an on-line measurement system for cathode preparation, which used measure pressure activation chamber, sample temperature, photocurrent, spectral response curves, currents heating Cs oxygen dispensers during heat-cleaning or processes of cathodes. According these signals, present some simple real-time evaluation techniques cathode preparation. Several peaks are observed variations measured heat cleaning. These peaks corresponding desorption AsO, As 2 O 3 , Ga from surface at different temperatures, respectively, effect cleaning well, while signals during activation can be analyze optimize technique. revised quantum efficiency equation, many parameters cathodes obtained fitting spectral response curves. these parameters, cathode material evaluated.