Systematic evaluation of fast neutron sensing with Cesium Hafnium Chloride

Cesium Hafnium Chloride (CHC) is a promising new scintillator for dual mode sensing of both neutrons and gamma-rays. The high chlorine content allows for both Cl-35(n,p)S-35 and Cl-35(n, alpha)P-32 reaction channels leading to reliable detection of fast neutrons. By utilizing pulse shape discrimination (PSD), these neutron interactions may be reliably separated from gamma-ray signals with a high figure-of-merit (FOM) after optimization of the PSD algorithm. In this study, the PSD algorithm settings for CHC were systematically investigated using a bare Cf-252 and a lead-shielded plutonium beryllium neutron source. It was found that the PSD algorithm settings affects both the FOM and the neutron detection efficiency, but a FOM as high as 4.5 for alpha particles was observed in one data processing scenario. Further, an intrinsic 5 parts per million alpha-emitting contamination was observed in the sample, which we attribute to natural uranium.

Automated summary

Cesium Hafnium Chloride (CHC) is a potential scintillator for dual mode sensing of neutrons and gamma-rays. Its high chlorine content allows for reliable detection of fast neutrons, and with pulse shape discrimination (PSD), neutron signals can be separated from gamma-ray signals effectively. This study systematically investigates the PSD algorithm settings for CHC using different neutron sources, and finds that the settings affect the figure-of-merit (FOM) and neutron detection efficiency.