Discrimination of high-Z materials in sealed containers with cosmic ray muons

Abstract

Muon scattering tomography (MST) is a method for using cosmic muons to scan cargo containers and vehicles for special nuclear materials. Some attempts for material identification have been made before, however, for high-Z materials like uranium with benign shielding materials of tungsten or lead, the discrimination efficiency cannot satisfy the practical demands. In this paper, a promising method of distinguishing high-Z materials using muon tomography is presented, utilizing previous knowledge of the high-Z objects' position inside a sealed container and distinguishing them from similar materials. In particular, simulations are performed in order to distinguish a block of uranium from blocks of lead or tungsten with the same size inside a sealed container. The results show that by applying this method it is possible to discriminate high-Z materials within an acceptable timescale. The effects of muon momentum uncertainty and spatial resolution of position sensitive detector for muon radiography are also carefully studied.