A comparison of untagged gamma-ray and tagged-neutron yields from 241AmBe and 238PuBe sources

TL;DR

This study compares gamma-ray and neutron yields from 241AmBe and 238PuBe sources, finding similar distribution shapes but differing in yield magnitudes, with 238PuBe producing significantly more gamma-rays and neutrons.

Contribution

It provides a direct comparison of untagged gamma-ray and tagged-neutron yields from two different mixed-field sources under consistent experimental conditions.

Findings

238PuBe produces 2.6 times more 4.44 MeV gamma-rays.

238PuBe yields 2.4 times more neutrons.

Distribution shapes are similar and agree with previous data.

Abstract

Untagged gamma-ray and tagged-neutron yields from 241AmBe and 238PuBe mixed-field sources have been measured. Gamma-ray spectroscopy measurements from 1 - 5 MeV were performed in an open environment using a CeBr3 detector and the same experimental conditions for both sources. The shapes of the distributions are very similar and agree well with previous data. Tagged-neutron measurements from 2 - 6 MeV were performed in a shielded environment using a NE-213 liquid-scintillator detector for the neutrons and a YAP(Ce) detector to tag the 4.44 MeV gamma-rays associated with the de-excitation of the first excited state of 12C. Again, the same experimental conditions were used for both sources. The shapes of these distributions are also very similar and agree well with previous data, each other, and the ISO recommendation. Our 238PuBe source provides approximately 2.6 times more 4.44 MeV gamma-rays and 2.4 times more neutrons over the tagged-neutron energy range, the latter in reasonable agreement with the original full-spectrum source-calibration measurements performed at the time of their acquisition.