The Comprehensive Nuclear-Test-Ban Treaty (CTBT) is supported by a global network of monitoring stations that perform high-resolution gamma-spectrometry on air filter samples for the identification of 85 radionuclides. At the UK CTBT Radionuclide Laboratory (GBL15), a novel cosmic veto gamma-spectrometer has been developed to improve the sensitivity of station measurements, providing a mean background reduction of 80.8% with mean MDA improvements of 45.6%. The CTBT laboratory requirement for a140Ba MDA is achievable after 1.5 days counting compared to 5-7 days using conventional systems. The system consists of plastic scintillation plates that detect coincident cosmic-ray interactions within an HPGe gamma-spectrometer using the Canberra LynxTMmulti-channel analyser. The detector is remotely configurable using a TCP/IP interface and requires no dedicated coincidence electronics. It would be especially useful in preventing false-positives at remote station locations (e.g. Halley, Antarctica) where sample transfer to certified laboratories is logistically difficult. The improved sensitivity has been demonstrated for a CTBT air filter sample collected after the Fukushima incident. © 2014 Elsevier B.V.
Burnett, J. L., & Davies, A. V. (2014). Cosmic veto gamma-spectrometry for Comprehensive Nuclear-Test-Ban Treaty samples. Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 747, 37–40. https://doi.org/10.1016/j.nima.2014.02.027