Gamma dose rate monitoring using a Silicon Photomultiplier-based plastic scintillation detector

Plastic scintillation detectors represent an efficient, cost-effective, customizable solution for assessment of gamma radiation fields in the context of nuclear security, environmental radiation survey, radiological and nuclear incidents response (RNe) and dosimetry for radiation protection purposes. Solid state light readout technologies such as Silicon Photomultiplier diodes (SiPM) are characterized by low operational voltage, mechanical robustness, compact dimensions, and fast pulse rise-time. Due to these intrinsic advantages, Silicon Photomultiplier diodes have been progressively replacing Photomultiplier Tube-based gamma detection technologies in a great part of these applications. In this experimental study, a gamma energy calibration and a dose rate calculation algorithm are discussed and implemented onto the SiPM-based Flat Panel Gamma detector (FPG) developed by Arktis Radiation Detectors Ltd (Zurich, Switzerland). The FPG detector has been deployed and studied in the framework of research projects on RNe technologies, involving its use on unmanned aerial and ground vehicle such as drones and robots. This work moved from the need for end users to have an accurate and reliable dose rate assessment when operating in the field, especially in the context of RNe response. Results are presented in terms of gamma dose rate accuracy obtained by laboratory measurements using radionuclide sources emitting in the 0.059 - 1.333 MeV gamma energy range, compared to theoretical dose rate calculations.