Development of a 500-kV photo-cathode DC gun for the ERL light sources in Japan

西森 信行; 永井 良治; 飯島 北斗; 羽島 良一; 山本 将博*; 武藤 俊哉*; 本田 洋介*; 宮島 司*; 栗木 雅夫*; 桑原 真人*; et al.

Proceedings of 31st International Free Electron Laser Conference (FEL 2009), p.277 - 280, 2009/08

Energy recovery linac (ERL) based next generation light sources such as X-ray oscillator require high brightness electron gun. We have developed a 500-kV, 10-mA photocathode DC gun by the collaboration efforts of JAEA, KEK, Hiroshima University and Nagoya University. A segmented cylindrical ceramic insulator with guard rings is employed to improve stability and robustness at high voltage operation by keeping secondary electrons away from the ceramic surface. A Cockcroft-Walton power supply is installed in a SF6 tank and high voltage test up to 550 kV was successfully done. All the vacuum chambers are made of chemically polished titanium alloy with very low out-gassing. A photocathode preparation system was assembled and vacuum test is performed. Up-to-date status of the gun development will be presented in detail.