Evaluation of plastic scintillating fibers coating technique for muon imaging detector using a Compton-coincidence-technique system

This study is devoted to studying the performance of plastic scintillating fibers (PSFs) for a high-position-resolution muon imaging detector. A test system based on the Compton coincidence technique is designed to study the light collection of the PSFs. When Compton scattering occurs between the PSFs and gamma ray emitted by the collimated radioactive source, the PSF detector has detected the definite energy of recoiled electrons, and the coincidence detector has detected the energy of scattered photons. Four groups of PSFs were tested, three of which were wrapped with the Enhanced Specular Reflector (ESR) in different ways. The experimental results show that the light collection of the PSF detector can be increased by wrapping the PSFs with ESR and leaving an air gap between the PSF and the ESR. Meanwhile, the light collection is increased while the position where Compton scattering occurs in the PSF is closer to the silicon photomultiplier (SiPM). This study provides a method for measuring the light collection in narrow PSFs. In conclusion, the presence and fine wrapping of the ESR ensure the isolation and position accuracy in the arrays of PSFs.