Replacement of a Photomultiplier Tube with Silicon Photomultipliers for use in Safeguards Applications

TL;DR

This study compares silicon photomultipliers (SiPMs) and traditional photomultiplier tubes (PMTs) in radiation detection, demonstrating SiPMs as a viable, more temperature-robust alternative for safeguards applications involving uranium enrichment measurement.

Contribution

The paper introduces the use of SiPM arrays as a replacement for PMTs in scintillation detectors, highlighting their temperature stability and suitability for nuclear safeguards.

Findings

SiPMs can be effectively biased to mitigate temperature effects.

SiPM-based detectors provide comparable performance to PMTs in uranium enrichment detection.

SiPMs offer advantages in size, fragility, and voltage requirements.

Abstract

We compared the performance of a SiPM array and a PMT in a laboratory setting using a single 5.08x5.08-cm cylindrical sodium iodide scintillating crystal. Photomultiplier tubes (PMTs) are the most commonly used device to monitor scintillating materials for radiation detection purposes. The systems are sometimes limited by disadvantages in the PMTs that may degrade their performance, including temperature dependence and variation with magnetic field. Instrumentation engineering must also contend with a potentially large volume relative to the active scintillator volume, fragility, and high voltage requirements. One possible alternative is an array of silicon photomultipliers (SiPMs). Measurements were made with a 5.04x5.04-cm sensL J-series SiPM array and a 7.62cm Hamamatsu PMT. We demonstrated how the SiPM bias can be sufficiently altered to remove the effects of temperature variation encountered in environments where nuclear safeguards work is often performed. Finally, we evaluated a method of determining enrichment levels of ${}^{235}U$ at various levels and shielding configurations, using both the PMT-mounted and SiPM-mounted scintillator.