Response of a Li-glass/multi-anode photomultiplier detector to collimated thermal-neutron beams

TL;DR

This study evaluates a Li-glass scintillator detector's ability to accurately detect thermal neutrons with high spatial resolution using a multi-anode photomultiplier, focusing on pixel response and event localization.

Contribution

It introduces a detailed analysis of the detector's pixel response and demonstrates effective neutron position detection with ~5 mm resolution using threshold optimization.

Findings

Approximately 80% of neutron events are detected in a single pixel at optimal threshold.

The detector achieves ~5 mm position resolution in X and Y directions.

Lower thresholds increase pixel multiplicity but maintain ~5 mm localization accuracy.

Abstract

The response of a position-sensitive Li-glass scintillator detector being developed for thermal-neutron detection with 6 mm position resolution has been investigated using collimated beams of thermal neutrons. The detector was moved perpendicularly through the neutron beams in 0.5 to 1.0 mm horizontal and vertical steps. Scintillation was detected in an 8 X 8 pixel multi-anode photomultiplier tube on an event-by-event basis. In general, several pixels registered large signals at each neutron-beam location. The number of pixels registering signal above a set threshold was investigated, with the maximization of the single-hit efficiency over the largest possible area of the detector as the primary goal. At a threshold of ~50% of the mean of the full-deposition peak, ~80% of the events were registered in a single pixel, resulting in an effective position resolution of ~5 mm in X and Y. Lower thresholds generally resulted in events demonstrating higher pixel multiplicities, but these events could also be localized with ~5 mm position resolution.