title: Simultaneous measurement of tritium and radiocarbon by ultra-low-background proportional counting.
abstract: Use of ultra-low-background capabilities at Pacific Northwest National Laboratory provide enhanced sensitivity for measurement of low-activity sources of tritium and radiocarbon using proportional counters. Tritium levels are nearly back to pre-nuclear test backgrounds (~2-8 TU in rainwater), which can complicate their dual measurement with radiocarbon due to overlap in the beta decay spectra. We present results of single-isotope proportional counter measurements used to analyze a dual-isotope methane sample synthesized from ~120mg of H2O and present sensitivity results.
authors.affiliation: Pacific Northwest National Laboratory, 902 Battelle Blvd, MSIN J4-65, Richland, WA 99352, USA. Electronic address: Emily.mace@pnnl.gov.
authors.forename: Emily
authors.initials: E
authors.lastname: Mace
authors.affiliation: Pacific Northwest National Laboratory, 902 Battelle Blvd, MSIN J4-65, Richland, WA 99352, USA.
authors.forename: Craig
authors.initials: C
authors.lastname: Aalseth
authors.affiliation: Pacific Northwest National Laboratory, 902 Battelle Blvd, MSIN J4-65, Richland, WA 99352, USA.
authors.forename: Tom
authors.initials: T
authors.lastname: Alexander
authors.affiliation: Pacific Northwest National Laboratory, 902 Battelle Blvd, MSIN J4-65, Richland, WA 99352, USA.
authors.forename: Henning
authors.initials: H
authors.lastname: Back
authors.affiliation: Pacific Northwest National Laboratory, 902 Battelle Blvd, MSIN J4-65, Richland, WA 99352, USA.
authors.forename: Anthony
authors.initials: A
authors.lastname: Day
authors.affiliation: Pacific Northwest National Laboratory, 902 Battelle Blvd, MSIN J4-65, Richland, WA 99352, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Hoppe
authors.affiliation: Pacific Northwest National Laboratory, 902 Battelle Blvd, MSIN J4-65, Richland, WA 99352, USA.
authors.forename: Martin
authors.initials: M
authors.lastname: Keillor
authors.affiliation: Pacific Northwest National Laboratory, 902 Battelle Blvd, MSIN J4-65, Richland, WA 99352, USA.
authors.forename: Jim
authors.initials: J
authors.lastname: Moran
authors.affiliation: Pacific Northwest National Laboratory, 902 Battelle Blvd, MSIN J4-65, Richland, WA 99352, USA.
authors.forename: Cory
authors.initials: C
authors.lastname: Overman
authors.affiliation: Pacific Northwest National Laboratory, 902 Battelle Blvd, MSIN J4-65, Richland, WA 99352, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Panisko
authors.affiliation: Pacific Northwest National Laboratory, 902 Battelle Blvd, MSIN J4-65, Richland, WA 99352, USA.
authors.forename: Allen
authors.initials: A
authors.lastname: Seifert
keywords: Dual-isotope measurements; Proportional counting; Radiocarbon; Tritium; Ultra-low-background