Development status of photocathode DC-gun for ERL light source

We report the development status of an NEA-GaAs photocathode DC-gun for an energy recovery linac (ERL) light source. The ERL light source requires large current, low emittance and ultra-short bunched electron beams to generate high brightness, coherent and ultra-short X-rays. In order to realize the high quality beams, the NEA-GaAs photocathode was chosen as the electron source, and the construction of the DC-gun started at Atomic Energy Agency (JAEA) to evaluate the performance of the quantum efficiency, the lifetime and the thermal emittance. The gun was designed on the basis of JAEA ERL-FEL to provide the beam with the energy of 250 keV and the average current of 50 mA. Until now, a conditioning of high voltage power supply was finished and the target voltage of 250 kV was accomplished. (author)