Source test of the prototype neutron detector for the large-acceptance multipurpose spectrometer at RAON

Abstract

A neutron detector array will be essential for the study of the nuclear symmetry energy in the large-acceptance multipurpose spectrometer (LAMPS) at the planned rare-isotope beam facility RAON in Korea. We have built the prototype neutron detector for LAMPS and examined its performance by using radiation sources. For data taking, we tested the voltage-threshold discriminator (VTD) and the constant-fraction discriminator (CFD) modules for the pulse process. The intrinsic time resolution of the prototype detector is estimated to be 723 ps for VTD and 488 ps for CFD. The fission neutrons and gammas emitted from Cf-252 can be clearly separated in the time distribution. We reconstruct the energy spectrum of the spontaneous fission neutrons from Cf-252, which can be described well by using the empirical Watt spectrum.