Measuring cosmic-ray intensity using balloon-borne silicon photomultipliers

Photomultiplier tubes are commonly used to read out scintillator and Cherenkov detectors in cosmic-ray experiments, but they operate using high voltages that require complex potting schemes to prevent dielectric breakdown in the low-pressure environment encountered at balloon float altitudes. Silicon photomultipliers (SiPMs) are a relatively new light detection technology that operate at considerably lower voltages and do not require encapsulation to function in low pressure. As part of a student research project, a simple cosmic-ray detector was constructed using SiPM technology and flown to an altitude of ~120,000ft. The data gathered in flight is consistent with previous observations, demonstrating that this technology is mature enough for use in cosmic-ray ballooning applications.