Fast neutron sensitivity of neutron detectors based on boron-10 converter layers

TL;DR

This paper investigates the sensitivity of boron-10 based neutron detectors to fast neutrons, analyzing their response and underlying physics to improve performance amid 3He shortages.

Contribution

It provides the first detailed study of fast neutron sensitivity in 10B-based thermal neutron detectors, including response analysis and physical mechanism explanations.

Findings

Fast neutron sensitivity depends on energy threshold settings.

Theoretical and simulation models explain the detector response.

Results inform optimization of detector performance.

Abstract

In the last few years many detector technologies for thermal neutron detection have been developed in order to face the shortage of 3He, which is now much less available and more expensive. Moreover the 3He-based detectors can not fulfil the requirements in performance, e.g. the spatial resolution and the counting rate capability needed for the new instruments. The Boron-10-based gaseous detectors have been proposed as a suitable choice. This and other alternatives technologies are being developed at ESS. Higher intensities mean higher signals but higher background as well. The signal-to-background ratio is an important feature to study, in particular the gamma-ray and the fast neutron contributions. This paper investigates, for the first time, the fast neutrons sensitivity of 10B-based thermal neutron detector. It presents the study of the detector response as a function of energy threshold and the underlying physical mechanisms. The latter are explained with the help of theoretical considerations and simulations.