Evaluation of coded aperture radiation detectors using a Bayesian approach

Abstract

Introduction. We investigate the utility of coded aperture (CA) for roadside radiation threat detection applications. With coded aperture, information in the form of photon quantity is traded for directional information.Whether and in what scenarios this trade-off is beneficial is the focus of this study. We quantify the impact of a masking approach by comparing performance with an unmasked approach in terms of both detection and localization of a roadside nuclear threat. We simulate many instances of a drive-by scenario via Monte Carlo using empirical observations from the RadMAP project [1] to obtain background photons and synthetic injection of threat source. Simulation results suggest that at 0.1%false positive rate (FPR) the masked detector suffers 20-50% loss of detection probability for weak sources, but only 1-1.5% for moderate source intensities. The masked approach also demonstrates consistent improvement in localization performance ranging from 0.7-2.2m across all source intensities investigated.