Comparison between silicon photomultipliers and photomultiplier tubes for pulse shape discrimination with stilbene

A stilbene crystal was coupled to a silicon photomultiplier (SiPM) to assess the performance of the detector's pulse shape discrimination (PSD) between fast neutrons and gamma rays. Pulses were digitized from a measurement of Cf-252 and digital charge comparison was used to perform PSD. The stilbene crystal was then coupled to a photomultiplier tube (PMT) and the measurement was repeated. The PSD performance when using the SiPM was compared to that of the system using the PMT. Both systems demonstrate efficient ability to discriminate between neutrons and gamma rays. While PMTs have long been the standard technology for light readout, SiPMs show similar capabilities while being less expensive, significantly more compact in size, significantly less sensitive to magnetic fields, and having lower power requirements. Potential drawbacks of SiPMs include elevated levels of noise and nonlinearity at high energies.