Adding the ability to quantify activity to a Radionuclide Identification Device

The SPIR-Ace, originally a Mirion Technologies’ Radionuclide Identification Device (RID), has been updated to incorporate the ability to not only rapidly identify radionuclides but also allows the quantification of the radiactive material being measured. This is done by making use of Canberra’s ISOCSTM (In-Situ Object Counting System) methodology and GenieTM 2000 analysis software compatability. The SPIR-Ace is a hand held detection platform, equipped with a scintillation based detector, a 1024 channel Multi-Channel Analyzer (MCA) and a Geiger-Muller probe for measuring high dose rates. Available with either NaI(Tl) (1.4” diameter, 2” length) or LaBr3 (1” diameter, 1.3” length), the system is sensitive to gamma ray radiation between 20 -3000 keV. The work presented here will detail the ISOCSTM detector characterization process that allows compatibility of the system with the ISOCSTM efficiency calibration software. This includes a comprehensive measurement protocol to evaluate the full energy peak efficiency of the given system. An intermediate modeling stage is described, which allows the detector model to be validated with the benchmark measurements. The final stage of the characterization process will show the validation of the ISOCSTM efficiency calibrations. This work will also show the results of a series of verification measurements, using various measurement geometries and a range of radionuclides, including those of interest to the nuclear safeguards community. The results of this work show that the measured activities, making use of either the LaBr3 or the NaI systems, has agreement to the certified activities to within 25% or better when employing an efficiency calibration that originated from the ISOCSTM characterization.