Speaker
Description
The high-intensity, polarized electron source is a critical component for the electron-ion collider, requiring a polarized electron gun with higher voltage and higher bunch charge than any existing polarized electron source. At Brookhaven National Laboratory, we have built and successfully conditioned an inverted HVDC photoemission gun up to 350 kV. In this study, we report on the performance of a GaAs photocathode in generating 70 µA average current and up to 16 nC bunch charge with a long lifetime using a circularly polarized laser at a wavelength of 780 nm. We discuss the performance of the Distributed Bragg Reflector GaAs/GaAsP Super Lattice photocathode in the DC gun, and possible reasons for the observed peak QE wavelength shift are analyzed. In addition, the impact of DBR layer and laser on the lifetime has been discussed. Further investigations are required to assess the DBR GaAs sample and enhance the performance of the polarized electron gun.
