“…The technology for measurements of Xe‐135, Xe‐133m, Xe‐133, and Xe‐131m, complying with the CTBT requirements, has been tested and evaluated for operational purposes, under the International Noble Gas Experiment (Auer et al, ). Three types of automatic measurement systems—developed independently by France, Russia, and Sweden—are currently in use in the IMS network: (i) the SPALAX (Système de Prélèvement Atmosphérique en Ligne avec l'Analyse des radioXénons) (Fontaine et al, ; Topin et al, ), (ii) the SAUNA (Swedish Automatic Unit for Noble Gas Acquisition) (Ringbom et al, ), and (iii) the ARIX (Analyzer of Radioactive Isotopes of Xenon) (Dubasov et al, ). The underlying physical principles are similar for the three systems, while differing in their technical approaches.…”