Simulations of a Scintillator Compton Gamma Imager for Safety and Security

TL;DR

This paper presents simulations of a portable, all-scintillator Compton gamma imager using Monte Carlo methods to evaluate different scintillator materials for security applications.

Contribution

It compares four scintillator materials for the scatter detector, assessing their performance for a rugged gamma imaging device.

Findings

PVT has lower performance than inorganic scintillators.

All tested materials could meet security imaging requirements.

Inorganic scintillators outperform PVT in key metrics.

Abstract

We are designing an all-scintillator Compton gamma imager for use in security investigations and remediation actions involving radioactive threat material. To satisfy requirements for a rugged and portable instrument, we have chosen solid scintillator for the active volumes of both the scatter and absorber detectors. Using the BEAMnrc/EGSnrc Monte Carlo simulation package, we have constructed models using four different materials for the scatter detector: LaBr_3, NaI, CaF_2 and PVT. We have compared the detector performances using angular resolution, efficiency, and image resolution. We find that while PVT provides worse performance than that of the detectors based entirely on inorganic scintillators, all of the materials investigated for the scatter detector have the potential to provide performance adequate for our purposes.