Facilitating object imaging through the utilization of cosmic-ray muons mandates the precise delineation of muon trajectories, where the pinpoint localization of muon impact points assumes paramount importance for effective muon track reconstruction. Existing muon track detection systems necessitate the integration of multifaceted electronic channels to attain meticulous positioning of muon impact points. The construction of such detection systems is distinguished by its intricacy and entails substantial associated costs.

This study aims to achieve a design for a muon track detection system that is characterized by simplicity, low cost, and high precision.

The Geant4 software was applied to the simulation of detectors comprising square and circular plastic scintillators coupled with silicon photon multipliers (SiPMs) without segmentation. The SiPMs was used to collect the number of photons and the time triggering SiPM responsed as characteristic parameters in the simulation, and a uncut square and circular plastic scintillator detector with an area of 200 mm × 200 mm was constructed, with a thickness of 10 mm. The surface was coated with a TiO₂ reflective coating with a thickness of 0.11 mm and a reflectivity of 95%. Then, three types of artificial intelligence regression algorithms, i.e., extreme gradient boosting (XGBoost), multilayer perceptron (MLP) and long short-term memory (LSTM), were employed as the method for muon localization.

The simulation results demonstrate that LSTM algorithm achieves the highest accuracy among the three regression algorithms when photon number is considered as the characteristic parameter. Specifically, under the LSTM algorithm, the position resolution of a configuration comprising 12 SiPMs coupled to the upper surface of the detector can attain a resolution at the centimeter level. Furthermore, by employing photon number and trigger time as characteristic parameters, the position resolution of a setup involving only 6 SiPMs coupled to the side of the detector also reaches the centimeter level. Remarkably, these results align with the experimental findings obtained from a detector equipped with a photomultiplier tube (PMT) coupled to a large-area plastic scintillator.

This study employs the LSTM regression algorithm as the muon localization method, proposing a detector system structure for plastic scintillators with 6 SiPMs coupled to the side. The proposed structure is characterized by simplicity, low manufacturing cost, and achieves a positioning accuracy at the centimeter level.