Performance Simulation of Muon Detectors Based on Structural Design and Array Layout of Plastic Scintillators

The performances of muon detectors have prominent effects on the accuracy and application scenario of muon imaging. Previous studies have paid more attention to the performance improvements of muon detectors in the assembly of imaging systems and optimization of imaging algorithms, while, the structural design and array layout of plastic scintillators in muon detectors have received less attention. In this work, the simulation models of plastic scintillator, wavelength-shifting (WLS) fibers, and muon source are constructed in the Geant4 software. On this basis, different factors affecting light collection efficiency (LCE) have been investigated, including muon hitting position, plastic scintillator cross-sectional shape and size, and WLS fiber size and position. Meanwhile, the influences of scintillator array layout, average width, and muon energy on the position resolution performance of the detector are investigated. The constructive results have been listed as follows: (a) the longitudinal length of the plastic scintillator unit, the shape and size of the WLS fiber, and the position of the WLS fiber have a large impact on the LCE. (b) The Right-angled triangle staggered layout is suitable for small-sized scintillators with single-energy muon hitting, and the Rhombus staggered layout is suitable for large-sized scintillators with multiple-energy muon hitting. This work provides theoretical support for the structural design and array layout of plastic Scintillators, and it has an important significance as a guide for the design of the subsequent muography system.