Design and construction of an electron accelerator for a pulsed neutron facility at AIST

Abstract A new electron accelerator has been designed and is now under construction at AIST, Tsukuba, Japan. The accelerator will be used to produce a pulsed neutron beam for materials analysis. The design maximizes the yield of slow neutrons with high pulse temporal resolution as described in a previous publication [K. Kino et al., Nuclear Inst. and Methods in Physics Research, A 927 (2019) 407–418]. The accelerator is composed of a thermal cathode type electron gun with S-Band buncher/accelerator cavity followed by three, 2.9 m long S-Band acceleration cavities. High power RF is supplied by three klystron units, with klystron No.1 supplying both the electron gun and the 1st cavity, and klystrons No.2 and No.3 connected to the 2nd and 3rd cavities respectively. The design parameters of the accelerator are; pulse rate: 100 Hz, pulse length: 10 μs, electron current: 250 mA, electron energy: 40 MeV. Operating at these parameters a maximum beam power of around 10 kW will be delivered to the water-cooled Ta target for neutron production. In this report we will describe the design and construction of the electron accelerator.