Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

Rossendorf SRF gun is an electron source based on superconducting RF technology but use normal conducting photocathode. Cs2Te is chosen as the standard photocathode. A vacuum transport system with UHV is built to move the cathodes from cathode lab to ELBE accelerator hall. Up to now 34 Cs2Te photocathodes have been prepared in our cathode laboratory and eight of them have been operated in the SRF gun. Quantum efficiency of 1% and life time of months satisfy the gun operation. On the other hand, the SRF gun is a good test bench for various cathodes. Metal cathodes, such as Cu and Pb-coated-Nb, and semiconductors, as GaN and GaAs, were ever tested in it.
Now the activities in our cathode laboratory are guided to new photocathode materials with high Q.E. for high current electron sources. Cs3Sb and GaN(Cs) photocathodes have been tested as new candidates, and the design of a preparation system for GaAs(Cs, O) is ongoing. The first GaAs photocathode is planned in one year.