Temperature Dependence of the Time Resolution in a SiPM-Readout Plastic Scintillator for Cosmic-Ray Applications

Balloon- and space-borne cosmic-ray experiments employ plastic scintillators read out by silicon photomultipliers (SiPMs) to achieve picosecond-level time resolutions for triggering and particle identification. The performance of these systems can be affected by temperature variations encountered in flight. In this work, a time-of-flight (TOF) prototype consisting of a BC418 plastic scintillator bar coupled to Onsemi MICROFC-30050 SiPMs was constructed and tested under a controlled thermal environment between -20 and 20${}^{\circ }$C. Electrons from a ${}^{90}\text{Sr}$ source were used as a beam, and a dedicated differential preamplifier and coincidence triggering were implemented to study the detector response. A minimum time resolution of 160ps was achieved at an overvoltage of 3V, remaining stable across the tested temperature range and uniform along the scintillator bar.