A Digital Pulse-Shape Discriminating Unit for Neutron-Gamma Discrimination with NE213

A fast and stable digital pulse-shape discriminating unit has been developed for the moisture gauge using 252Cf as radiation source. This unit performs digital discrimination between neutrons and gamma-rays in conbination with the liquid scintillator NE213. Modern digital integrated circuits such as flash type A-D converter, a digital divider, a digital comparator and digital controled gated integrators compose the discrimination circuit. Neutrons and gamma-rays events are separately accumulated and applied for automatic stabilization by an integrated single-chip computer. The discriminating charastics are controled not only manually but also under a host computer by way of the GPIB. The performances of available event rates and long term stability are estimated around 100 kcps and 0.5 % respectively The actual circuit configuration and features are discussed in detail.