In order to solve the problem of low electron emission sensitivity of negative
electron affinity GaAs photocathode, mass spectrometer was used to analyze the
deflating components of GaAs glass bonded cathode assembly under high temperature
thermal radiation degassing, and the atomic surface of GaAs electron emission
layer was obtained. The results showed that: 150 ℃ was the surface venting of the
component, 450 ℃ was the internal venting of the material, 580 ℃ was the obtained
temperature of the clean surface, and more than 650 ℃ , there was As evaporation
in the GaAs emission layer. This indicates that strictly controlling the surface clean
temperature of emission layer is the key to ensure the sensitivity of cathode.