3He neutron proportional counter performance in high gamma-ray dose environments

We have studied the properties of 3He neutron proportional tubes in gamma-ray environments to accommodate particular programmatic needs. In this paper, we summarize our results and experience to date into a single resource. Over the course of this study we have extended the operation of 3He tubes from a maximum gamma-ray dose of a few Rad/h per active foot to beyond 200 Rad/h per active foot (30.5 cm). We have quantified the gamma-ray pileup in a variety of tube designs in a manner useful to system users and designers. We have developed a new hybrid 3He tube that is suitable for prolonged high-dose exposure to gamma rays.