Low Energy Light Yield of Fast Plastic Scintillators

TL;DR

This study measures the proton light yield of commercial fast plastic scintillators over a broad energy range to improve neutron imaging systems for nuclear material detection.

Contribution

It provides new proton light yield data for EJ-200, EJ-204, and EJ-208 scintillators using a double time-of-flight technique, aiding neutron imaging development.

Findings

Proton light yield data obtained down to 50 keV recoil energy.

Enhanced understanding of scintillator response for neutron detection.

Data supports improved event reconstruction in neutron imaging systems.

Abstract

Compact neutron imagers using double-scatter kinematic reconstruction are being designed for localization and characterization of special nuclear material. These neutron imaging systems rely on scintillators with a rapid prompt temporal response as the detection medium. As n-p elastic scattering is the primary mechanism for light generation by fast neutron interactions in organic scintillators, proton light yield data are needed for accurate assessment of scintillator performance. The proton light yield of a series of commercial fast plastic organic scintillators---EJ-200, EJ-204, and EJ-208---was measured via a double time-of-flight technique at the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory. Using a tunable deuteron breakup neutron source, target scintillators housed in a dual photomultiplier tube configuration, and an array of pulse-shape-discriminating observation scintillators, the fast plastic scintillator light yield was measured over a broad and continuous energy range down to proton recoil energies of approximately 50 keV. This work provides key input to event reconstruction algorithms required for utilization of these materials in emerging neutron imaging modalities.