Development of an electron gun for the ERL light source in Japan

Nishimori, Nobuyuki; Hajima, Ryoichi; Iijima, Hokuto; Nagai, Ryoji; Nishitani, Tomohiro*

An electron gun has been developed at Japan Atomic Energy Agency (JAEA) for the ERL light source project jointly launched by JAEA, KEK, and the Institute for Solid State Physics (ISSP) of the University of Tokyo. The electron bunch is generated from a NEA photocathode upon illumination of a drive laser pulse and is accelerated to 250keV by the DC high voltage applied between the cathode and anode. We have finished high voltage terminal test and started to assemble a preparation chamber for the photocathode. We have also measured life time and quantum efficiency of AlGaAs to find a photocathode having longer life time, higher quantum efficiency and smaller emittance than GaAs. In our preliminary test, AlGaAs has shown twice higher QE and 10 times longer life time than GaAs. In this talk, our current status of the gun development is presented.