Troy Robinson, Mattias Aldener, Matthew Goodwin, Steven Bell, Tomas Fritioff, Marc Abilama, Andy Pearce, John Keightley, Tracy Houghton, Matthew Watrous, Michael Foxe, Johnathan Slack
The Idaho National Laboratory (INL, USA), serves as a quality control laboratory for the Comprehensive Test Ban Treaty Organization. Unfortunately, INL lost its primary source of traceable 133Xe materials when the National Institute of Standards and Technology (NIST, USA) stopped producing this standard reference material. To address this gap, INL collaborated with the National Physical Laboratory (NPL, UK) in 2017 and 2018 through interlaboratory comparison experiments to validate INL's133Xe calibration. Following successful completion of these intercomparisons, two additional intercomparisons were performed in 2020 and 2021, incorporating a second radionuclide (131mXe) and three additional CTBTO affiliated analysis laboratories: Pacific Northwest National Laboratory (PNNL, USA), the Atomic Weapons Establishment (AWE, UK), and the Swedish Defense Research Agency (FOI, Sweden). Intercomparison results from all four exercises are presented and discussed.