Lead photocathodes

We present the results of our investigation of lead as a suitable photocathode material for superconducting rf injectors. Quantum efficiencies (QE) have been measured for a range of incident photon energies and compared to predictions from the three-step model of photoemission. A variety of cathode preparation methods have been used, including various lead plating techniques on a niobium substrate. The effects of operating at ambient and cryogenic temperatures and different vacuum levels on the cathode QE have also been studied