A high-resolution β-γ coincidence spectrometry system for radioxenon measurements

摘要

GBL15, the UK's noble gas certified Comprehensive Nuclear-Test-Ban Treaty (CTBT) radionuclide laboratory supports the International Monitoring System (IMS) through measurement of environmental radioxenon samples using β-γ coincidence spectrometry. GBL15 currently utilises a system comprised of NaI(Tl) γ-detectors and plastic scintillator β-detectors to measure coincident emissions from the four radioxenon isotopes of interest: ~(133)Xe, ~(135)Xe,~(131m)Xe and ~(133m)Xe. This paper reports on the setup, calibration and assessment of the CEA/Mirion-developed PIPSBox, used in coincidence setup with a high-purity germanium detector. The system has been configured to measure the signals from the four radionuclides of interest and demonstrates improved discrimination between signals and less interference compared to the current system. The coincident detection efficiencies are quantified through measurement of spiked radioxenon samples.