Characterization of Gadolinium-loaded Plastic Scintillator for Use as a Neutron Veto

TL;DR

This study develops and characterizes gadolinium-loaded plastic scintillators as solid neutron detectors, evaluating their optical properties and potential application as neutron vetoes in dark matter experiments.

Contribution

It introduces a new solid scintillator material doped with gadolinium, with measured optical properties and optimized light collection strategies for neutron detection.

Findings

Gadolinium-loaded scintillators show promising optical performance.

Monte Carlo simulations accurately predict trapping efficiency.

Potential application as neutron veto in dark matter detection.

Abstract

Scintillator doped with a high neutron-capture cross-section material can be used to detect neutrons via their resulting gamma rays. Examples of such detectors using liquid scintillator have been successfully used in high-energy physics experiments. However, a liquid scintillator can leak and is not as amenable to modular or complex shapes as a solid scintillator. Polystyrene-based scintillators from a variety of gadolinium compounds with varying concentrations were polymerized in our laboratory. The light output, emission spectra, and attenuation length of our samples were measured and light collection strategies using a wavelength shifting (WLS) fiber were evaluated. The measured optical parameters were used to tune a Geant4-based optical Monte Carlo, enabling the trapping efficiency to be calculated. This technology was also evaluated as a possible neutron veto for the direct detection dark matter experiment, Super Cryogenic Dark Matter Search (SuperCDMS).