Discrimination of particles in neutron detectors

Abstract

This work experimentally compares two charge preamplifiers used with 3He neutron detectors by means of digital pulse-shape analysis: a commercial Canberra and a prototype designed by the Universitat Polit`ecnica de Catalunya (UPC). Measurements were performed with moderated neutron, gamma, and background sources. A signal-processing algorithm that calculates the rise time was implemented. The Canberra system shows excellent discrimination, with a clear separation in the rise time versus energy plots. The prototype of a UPC requires a complementary method, the use of a cadmium filter, to allow correct neutron discrimination. The normalized pulse shapes confirm the differences in rise time for neutrons, gamma rays and microdischarges. Thus, the results demonstrate that the discrimination based on rise time is effective for both systems.