Standardisation of 223Ra by liquid scintillation counting techniques and comparison with secondary measurements. (January 2015)

• Record Type: Journal Article
• Authors: Keightley, John; Pearce, Andy; Fenwick, Andrew; Collins, Sean; Ferreira, Kelley; Johansson, Lena
• Is Part Of: Applied radiation and isotopes. Volume 95(2015:Jan.)
• Page Start: 114
• Page End: 121
• Publication Date: 2015-01
• Subjects: Ra-223 -- Calibration figure -- Dial setting -- Radioactivity -- Primary standardisation -- Liquid scintillation counting -- Digital coincidence counting -- DCC; Radiology -- Periodicals; Radiation -- Industrial applications -- Periodicals; Nuclear chemistry -- Periodicals; Internet resource; Periodical; 660.298
• DOI: 10.1016/j.apradiso.2014.10.009
• Languages: English
• ISSNs: 0969-8043

Abstract

Abstract: An aqueous solution of 223 Ra chloride in equilibrium with its decay progeny was standardised by liquid scintillation counting techniques. Since secular equilibrium with the decay progeny of 223 Ra had been established by the time of measurement, the apparent detection efficiency of 223 Ra was approximately 6 and was determined by both the CIEMAT/NIST efficiency tracing technique and the 4π(LS)-γ digital coincidence counting techniques. The results obtained were compared with γ-spectrometry and ionisation chamber measurements. Whilst the γ-spectrometry measurements were in agreement (albeit exhibiting a large spread (18%) in the individual activity estimations using the main γ-emissions), a significant discrepancy of the order of 9% was identified between the liquid scintillation counting results and those obtained using published calibration factors for a variety of radionuclide calibrators. Highlights: An aqueous solution of 223 Ra chloride was standardised by liquid scintillation counting. CIEMAT/NIST efficiency tracing and Digital Coincidence Counting were utilised. Calibration factors for a variety of radionuclide calibrators were calculated. A discrepancy of around 9% was identified utilising existing published calibration factors. γ-spectrometry measurements exhibited a large spread (18.3%) in the individual activity estimations using published γ-emissions.