Comparative Study of Gamma to Neutron Ratios of various (alpha, neutron) Neutron Sources

TL;DR

This study measures and compares gamma to neutron ratios of PuBe and PoBe sources using pulse shape discrimination and coincidence counting, revealing higher ratios than literature values and analyzing emission coincidences.

Contribution

It introduces a method to measure gamma to neutron ratios using PSD and coincidence counting, providing new data and analysis for PuBe and PoBe sources.

Findings

Gamma/neutron ratio for PuBe is 3.67 +/- 0.14.

Gamma/neutron ratio for PoBe is 1.13 +/- 0.05.

PoBe emits coincident gamma-rays/neutrons with 91.77% confidence.

Abstract

The gamma to neutron ratio is measured via Pulse Shape Discrimination (PSD) of a Plutonium Beryllium (PuBe) source and of a rudimentary constructed Polonium Beryllium (PoBe) source using one organic liquid scintillator detector and digital signal processing. Furthermore, two organic liquid scintillator detectors and digital signal processing is used to conduct coincidence counting on the PoBe source. Measured data is compared to literature. The gamma to neutron source ratio was found to be 3.67 +/- 0.14 and 1.13 +/- 0.05 for the PuBe and for the PoBe source respectively. Both ratios are above literature values for the respective neutron sources. Coincidence counting analysis showed that the PoBe source emitted two or more coincident gamma-rays or neutrons with a confidence level of 91.77 % using a coincident window of 40ns and a detector source distance of 1 mm.