One of the most conclusive evidence of a violation of CTBT is the presence in the subsoil air of elevated concentrations of 37Ar radionuclide, which is formed in large quantities in the interaction of neutrons with calcium, which is part of rocks. Traditionally, to measure the activity of 37Ar, proportional gas counters are used, which are filled with a counting gas prepared from samples of...
Advanced gamma-spectrometry systems have potential for higher-sensitivity analysis of CTBT relevant radionuclides in IMS samples. These systems include sophisticated multi-detector configurations that are capable of coincidence measurements with Compton and cosmic rejection. They can provide detection sensitivity 2-4 orders of magnitude higher than conventional gamma-spectrometry used for IMS...
As radioxenon samples are collected around the world at the CTBTO IMS stations, a subset of those are sent to radionuclide laboratories around the world for re-analysis. PNNL operates the U.S. Noble Gas Laboratory (US-NGL), which was certified in December of 2016. The laboratory currently has one certified detector, but there are potential scenarios where additional throughout is desired. Two...
