title: A gamma-gamma coincidence/anticoincidence spectrometer for low-level cosmogenic (22)Na/(7)Be activity ratio measurement.
abstract: In this study, a digital gamma-gamma coincidence/anticoincidence spectrometer was developed and examined for low-level cosmogenic (22)Na and (7)Be in air-filter sample monitoring. The spectrometer consists of two bismuth germanate scintillators (BGO) and an XIA LLC Digital Gamma Finder (DGF)/Pixie-4 software and card package. The spectrometer design allows a more selective measurement of (22)Na with a significant background reduction by gamma-gamma coincidence events processing. Hence, the system provides a more sensitive way to quantify trace amounts of (22)Na than normal high resolution gamma spectrometry providing a critical limit of 3 mBq within a 20 h count. The use of a list-mode data acquisition technique enabled simultaneous determination of (22)Na and (7)Be activity concentrations using a single measurement by coincidence and anticoincidence mode respectively.
authors.affiliation: Radiation Protection Bureau of Health Canada, 775 Brookfield Road, Ottawa, Ontario K1A 1C1, Canada. Electronic address: weihua.zhang@hc-sc.gc.ca.
authors.forename: Weihua
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Radiation Protection Bureau of Health Canada, 775 Brookfield Road, Ottawa, Ontario K1A 1C1, Canada.
authors.forename: Kurt
authors.initials: K
authors.lastname: Ungar
authors.affiliation: Radiation Protection Bureau of Health Canada, 775 Brookfield Road, Ottawa, Ontario K1A 1C1, Canada.
authors.forename: Matthew
authors.initials: M
authors.lastname: Stukel
authors.affiliation: Radiation Protection Bureau of Health Canada, 775 Brookfield Road, Ottawa, Ontario K1A 1C1, Canada.
authors.forename: Pawel
authors.initials: P
authors.lastname: Mekarski
mesh_terms: D001608:Beryllium / Q000032:analysis*; D001729:Bismuth / Q000737:chemistry; D005857:Germanium / Q000737:chemistry; D057230:Limit of Detection; D011834:Radiation Monitoring / Q000295:instrumentation* / Q000379:methods*; D011868:Radioisotopes / Q000032:analysis*; D012588:Scintillation Counting / Q000295:instrumentation; D012964:Sodium / Q000032:analysis*; D012979:Sodium Radioisotopes / Q000032:analysis; D013051:Spectrometry, Gamma / Q000295:instrumentation*
chemical_list: D011868:Radioisotopes; D012979:Sodium Radioisotopes; D005857:Germanium; C042364:bismuth germanium oxide; D012964:Sodium; D001608:Beryllium; D001729:Bismuth
keywords: (22)Na; (7)Be; BGO detector; Gamma–Gamma coincidence/anticoincidence