Study of methods for reducing the intrinsic background of a neutron detector for rare spontaneous fission events

Abstract The cosmic radiation protection of a neutron detector is described. The combination of a passive concrete shielding and a plastic scintillator anticoincidence system allows one to decrease the background of a 3 He-filled counter detector by a factor of about 1000, the loss in the spontaneous fission count rate being equal to approximately 45%. The possible applications of the low-background neutron detector are proposed.