Development of a 500-kV photocathode DC gun for ERLs

ERLのための500kV光陰極DC電子銃の開発

西森 信行; 永井 良治; 山本 将博*; 本田 洋介*; 宮島 司*; 飯島 北斗*; 栗木 雅夫*; 桑原 真人*; 奥見 正治*; 中西 彊*; 羽島 良一

Nishimori, Nobuyuki; Nagai, Ryoji; Yamamoto, Masahiro*; Honda, Yosuke*; Miyajima, Tsukasa*; Iijima, Hokuto*; Kuriki, Masao*; Kuwahara, Makoto*; Okumi, Shoji*; Nakanishi, Tsutomu*; Hajima, Ryoichi

An electron gun capable of delivering high current and high brightness electron beam is indispensable for ERL light sources. A high voltage photocathode DC gun is a promising gun for such new light sources. It is however difficult to apply DC high voltage on a ceramic insulator with a rod supporting cathode electrode because of field emission from the rod. In order to mitigate the problem, we have employed a segmented insulator with rings which guard the ceramics from the field emission. We have recently succeeded in applying 500-kV on the ceramics for eight hours without any discharge. Our recent development will be presented at the workshop.