Development of a low background liquid scintillation counter for a shallow underground laboratory. (November 2015)

• Record Type: Journal Article
• Authors: Erchinger, J.L.; Aalseth, C.E.; Bernacki, B.E.; Douglas, M.; Fuller, E.S.; Keillor, M.E.; Morley, S.M.; Mullen, C.A.; Orrell, J.L.; Panisko, M.E.; Warren, G.A.; Williams, R.O.; Wright, M.E.
• Is Part Of: Applied radiation and isotopes. Volume 105(2015:Nov.)
• Page Start: 209
• Page End: 218
• Publication Date: 2015-11
• Subjects: Liquid scintillation counting -- Low background -- Shallow underground laboratory; Radiology -- Periodicals; Radiation -- Industrial applications -- Periodicals; Nuclear chemistry -- Periodicals; Internet resource; Periodical; 660.298
• DOI: 10.1016/j.apradiso.2015.08.027
• Languages: English
• ISSNs: 0969-8043

Abstract

Abstract: Pacific Northwest National Laboratory has recently opened a shallow underground laboratory intended for measurement of low-concentration levels of radioactive isotopes in samples collected from the environment. The development of a low-background liquid scintillation counter is currently underway to further augment the measurement capabilities within this underground laboratory. Liquid scintillation counting is especially useful for measuring charged particle (e.g., β and α ) emitting isotopes with no (or very weak) gamma-ray yields. The combination of high-efficiency detection of charged particle emission in a liquid scintillation cocktail coupled with the low-background environment of an appropriately designed shield located in a clean underground laboratory provides the opportunity for increased-sensitivity measurements of a range of isotopes. To take advantage of the 35 m-water-equivalent overburden of the underground laboratory, a series of simulations have evaluated the scintillation counter's shield design requirements to assess the possible background rate achievable. This report presents the design and background evaluation for a shallow underground, low background liquid scintillation counter design for sample measurements. Abstract : Highlights: Graded-shielding can produce an ultra-low-background liquid scintillation counter. Location in a shallow underground cleanroom further enhances background reduction. A novel light collection design and selected low background materials are utilized. The background is predicted to be 10–100 times below typical commercial systems. Simulations tentatively predict a background rate of order 10 counts per day.