Investigation of YSO-SiPM detector response for alpha spectroscopy applications

Alpha-particle spectroscopy is widely used in nuclear physics, radiation monitoring, safeguards, and environmental measurements. Conventional silicon detectors provide excellent spectrometric performance; however, their application in portable or harsh-environment instrumentation may be limited by mechanical fragility, radiation sensitivity, and operational constraints. Scintillator-based detectors coupled to silicon photomultipliers (SiPMs) represent a promising alternative because of their compactness, robustness, and simplified integration with modern electronics. Despite the favorable scintillation properties of yttrium orthosilicate (YSO), its applicability for alpha-particle spectroscopy has received limited investigation.

The response of a YSO scintillator coupled to a Hamamatsu S13360-3050 multi-pixel photon counter (MPPC) array was investigated using alpha particles emitted from a ²³⁸Pu source. A 10 × 10 × 10 mm ³ YSO crystal was coupled to the SiPM array and read out using CAEN digitization electronics. Alpha-particle energies in the approximate range from 0.4 MeV to 5.5 MeV were obtained by varying the air-layer thickness between the radioactive source and detector. Signal acquisition was performed using a CAEN DT5720 digitizer operated in self-trigger mode, while offline waveform processing was performed using ROOT-based software.

The YSO-SiPM detector exhibited stable and approximately linear response characteristics across the investigated energy interval. The measured deviation from linearity was approximately 3%. The experimentally determined alpha-particle flight distance in air was measured as 40.58 ± 0.87 mm, in good agreement with SRIM simulations predicting approximately 42 mm. The measured energy resolution varied from approximately 10.5% at 5.5 MeV to approximately 21% at lower alpha-particle energies near 0.4 MeV. Alpha-particle signals remained clearly distinguishable down to approximately 500 keV.

The obtained results demonstrate that the YSO-SiPM configuration represents a compact and mechanically robust detector solution for alpha-particle spectroscopy. Although the energy resolution remains inferior to conventional silicon alpha detectors, the investigated system offers important practical advantages including operation under ambient conditions, simplified electronics integration, scalability, and suitability for portable or harsh-environment nuclear instrumentation.