High voltage test of a 500-kV DC electron gun for an ERL light source

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

A 500-kV, 10-mA photocathode DC gun has been designed and is now under fabrication by the collaboration efforts of JAEA, KEK, Hiroshima University and Nagoya University. We have adopted a multiple-stacked cylindrical ceramic insulator, because this type of ceramic insulator has shown good stability and robustness at the 250-kV JAEA FEL gun and the 200-kV Nagoya polarized gun. The Cockcroft-Walton voltage multiplier, the ceramic insulator, the vacuum chambers has been fabricated and a high-voltage test will be successfully achieved soon. Up-to-date status of the gun development is presented in detail.