Study on reduction of gamma-ray noise for a pixel-type position-sensitive Li-glass neutron detector

A pixel-type position-sensitive Li-glass neutron detector has been developed in the Hokkaido University and applied to neutron transmission measurements for obtaining wavelength-dependent neutron images due to its high counting rate. This detector will be applied to monitor the time spectrum of the pulsed neutron beam for the neutron capture cross-section measurements at the Japan Spallation Neutron Source (JSNS). It turned out that the gamma-rays which were accompanied by neutron transmission measurements may be also detected by this detector and may affect wavelength-dependent neutron intensity. We have therefore studied experimentally and numerically the detector efficiency for gamma-rays as a function of photon energy. We have also investigated some practical methods to reduce the effects of gamma-rays on the position-sensitive Li-glass neutron detector by using the Hokkaido University 45MeV LINAC neutron source.