title: Ground surface ultralow background spectrometer: Active shielding improvements and coincidence measurements for the Gamma3spectrometer.
abstract: The ultralow background versatile spectrometer GAMMA3has been optimized with the following shielding improvements: (i) optimized nitrogen injection flux of 300Lh-1, and (ii) cosmic veto configuration with 9 scintillating plates. These improvements allow a reduction of 39% of the normalized integral background count rate down to 2.7±0.2min-1kgGe-1(40-2500keV energy range). Minimum Detectable Activities when performing direct γ-ray spectrometry or γ-γ coincidence spectrometry are compared.
authors.affiliation: CEA, DAM, DIF, F-91297 Arpajon, France. Electronic address: antoine.cagniant@cea.fr.
authors.forename: A
authors.initials: A
authors.lastname: Cagniant
authors.affiliation: CEA, DAM, DIF, F-91297 Arpajon, France.
authors.forename: O
authors.initials: O
authors.lastname: Delaune
authors.affiliation: CEA, DAM, DIF, F-91297 Arpajon, France.
authors.forename: M
authors.initials: M
authors.lastname: Réglat
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: P
authors.initials: P
authors.lastname: Gross
authors.affiliation: CEA, DAM, DIF, F-91297 Arpajon, France.
authors.forename: G
authors.initials: G
authors.lastname: Le Petit
keywords: CTBTO; Coincidence spectrometry; Gamma(3); Low-level gamma spectrometry