Development and Commissioning of a Compact Cosmic Ray Muon Imaging Prototype

TL;DR

This paper presents the design, construction, and testing of a compact cosmic ray muon imaging system capable of detecting high-Z materials like lead, with high efficiency and resolution, suitable for applications such as nuclear material inspection.

Contribution

The paper introduces a novel compact CRM imaging prototype with high detection efficiency, precise imaging capabilities, and material discrimination, advancing portable muon tomography technology.

Findings

Detection efficiency of about 98% for individual detectors

Position resolution of 2.5 mm for vertical muons

Ability to distinguish materials like Pb, Cu, Fe, Al

Abstract

Due to the muon tomography's capability of imaging high Z materials, some potential applications have been reported on inspecting smuggled nuclear materials in customs. A compact Cosmic Ray Muons (CRM) imaging prototype, Lanzhou University Muon Imaging System (LUMIS), is comprehensively introduced in this paper including the structure design, assembly, data acquisition and analysis, detector performance test, and material imaging commissioning etc. Casted triangular prism plastic scintillators (PS) were coupled with Si-PMs for sensitive detector components in system. LUMIS's experimental results show that the detection efficiency of an individual detector layer is about 98%, the position resolution for vertical incident muons is 2.5 mm and the angle resolution is 8.73 mrad given a separation distance of 40.5 cm. Moreover, the image reconstruction software was developed based on the Point of Closest Approach (PoCA) to detect lead bricks as our target. The reconstructed images indicate that the profile of the lead bricks in the image is highly consistent with the target. Subsequently, the capability of LUMIS to distinguish different materials, such as Pb, Cu, Fe, and Al, was investigated as well. The lower limit of response time for rapidly alarming high-Z materials is also given and discussed. The successful development and commissioning of the LUMIS prototype have provided a new solution option in technology and craftsmanship for developing compact CRM imaging systems that can be used in many applications.