Development status of the photocathode DC gun at JAEA

Iijima, Hokuto; Nagai, Ryoji; Nishimori, Nobuyuki; Hajima, Ryoichi; Minehara, Eisuke

The next generation light source via an energy recovery linac (ERL) is a powerful tool for various fields such as materials and life science. We are developing an electron gun which is the most important component for the ERL light source. An NEA-AlGaAs cathode is chosen to realize the large current and low emittance of the -beams. A 6-stages symmetric Cockcroft-Walton voltage multiplier provides the 250 keV of acceleration. The main part of the gun consists of Ti chambers which are low outgas materials. Therefore we have achieved Pa in vacuum. A load-lock system, which transfars the cathode between the load-lock, activation and main chambers in the vacuum, is employed. So far we observed the quantum efficiency of 1.5% in the preliminary experiment. The investigation of the making of NEA surface is continued to achieve the high quantum efficiency.