title: Spalax™ new generation: A sensitive and selective noble gas system for nuclear explosion monitoring.
abstract: In the context of the verification regime of the Comprehensive nuclear Test ban Treaty (CTBT), CEA is developing a new generation (NG) of SPALAX™ system for atmospheric radioxenon monitoring. These systems are able to extract more than 6cm(3) of pure xenon from air samples each 12h and to measure the four relevant xenon radioactive isotopes using a high resolution detection system operating in electron-photon coincidence mode. This paper presents the performances of the SPALAX™ NG prototype in operation at Bruyères-le-Châtel CEA centre, integrating the most recent CEA developments. It especially focuses on an innovative detection system made up of a gas cell equipped with two face-to-face silicon detectors associated to one or two germanium detectors. Minimum Detectable activity Concentrations (MDCs) of environmental samples were calculated to be approximately 0.1 mBq/m(3) for the isotopes (131m)Xe, (133m)Xe, (133)Xe and 0.4 mBq/m(3) for (135)Xe (single germanium configuration). The detection system might be used to simultaneously measure particulate and noble gas samples from the CTBT International Monitoring System (IMS). That possibility could lead to new capacities for particulate measurements by allowing electron-photon coincidence detection of certain fission products.
authors.affiliation: CEA, DAM, DIF, F-91297 Arpajon, France. Electronic address: gilbert.le-petit@cea.fr.
authors.forename: G
authors.initials: G
authors.lastname: Le Petit
authors.affiliation: CEA, DAM, DIF, F-91297 Arpajon, France.
authors.forename: A
authors.initials: A
authors.lastname: Cagniant
authors.affiliation: CEA, DAM, DIF, F-91297 Arpajon, France.
authors.forename: P
authors.initials: P
authors.lastname: Gross
authors.affiliation: CEA, DAM, DIF, F-91297 Arpajon, France.
authors.forename: G
authors.initials: G
authors.lastname: Douysset
authors.affiliation: CEA, DAM, DIF, F-91297 Arpajon, France.
authors.forename: S
authors.initials: S
authors.lastname: Topin
authors.affiliation: CEA, DAM, DIF, F-91297 Arpajon, France.
authors.forename: J P
authors.initials: JP
authors.lastname: Fontaine
authors.affiliation: CEA, DAM, DIF, F-91297 Arpajon, France.
authors.forename: T
authors.initials: T
authors.lastname: Taffary
authors.affiliation: CEA, DAM, DIF, F-91297 Arpajon, France.
authors.forename: C
authors.initials: C
authors.lastname: Moulin
keywords: Electron-photon coincidences; Nuclear explosion monitoring; Pipsbox™; Radioxenon; Spalax™