Characterization of the energy response of a LYSO+SiPM detector module for E//B NPA using [formula omitted] and hydrogen ions

Abstract

This article presents a novel application of the lutetium-yttrium oxyorthosilicate (LYSO) scintillator in a newly constructed neutral particle analyzer with a parallel electric and magnetic fields structure (E//B NPA). The LYSO scintillator, coupled to the silicon photomultiplier (SiPM) without a reflector, serves as the detector module in the E//B NPA. The LYSO+SiPM configuration offers numerous advantages for the NPA application, including high efficiencies, compact size, low voltage operation, and exceptional resistance to magnetic fields. The performance of a prototype detector module was studied using a radioactive source in conjunction with the 50 kV electron cyclotron resonance (ECR) ion source platform. The crosstalk of optical photons from adjacent detector modules was examined with two detectors, and it was determined to be negligible. The high-energy α spectra exhibited a distinctive two-shoulder structure, which arises from α particles impinging on different positions of the LYSO crystal surface. This observation was further investigated through Geant4 simulations. The detector module was found to have a low-energy limit of 10 keV for hydrogen ions. In the comprehensive measurements, linear energy responses were observed for α particles and hydrogen ions within the error bars. The relative light yield of α and hydrogen ions exhibited a different trend compared to that of γ rays or electrons, providing valuable insights for the study of non-proportionality of light yield for light ions in the LYSO scintillator.