The absolute activities of the pure beta-emitters Sr-89 and Y-90 have been determined by a direct method, namely the triple-to-double coincidence ratio (TDCR) efficiency calculation technique. This undertaking has extended further the number of radionuclides that have been standardized by this non-extrapolation liquid scintillation (LS) method. Both measurements were carried out within the framework of international key comparisons under the auspices of the International Bureau of Weights and Measures (BIPM). The TDCR results agreed well with those of other participating national laboratories, most using alternative (tracer) methods.
Reference:
Simpson, BRS and Van Wyngaardt, WM. 2006. Activity measurements of the high-energy pure beta-emitters Sr-89 and Y-90 by the TDCR efficiency calculation technique. Applied radiation and Isotopes, vol 64, 11 October, pp 1481-1484
Simpson, B., & Van Wyngaardt, W. (2006). Activity measurements of the high-energy pure beta-emitters Sr-89 and Y-90 by the TDCR efficiency calculation technique. http://hdl.handle.net/10204/1479
Simpson, BRS, and WM Van Wyngaardt "Activity measurements of the high-energy pure beta-emitters Sr-89 and Y-90 by the TDCR efficiency calculation technique." (2006) http://hdl.handle.net/10204/1479
Simpson B, Van Wyngaardt W. Activity measurements of the high-energy pure beta-emitters Sr-89 and Y-90 by the TDCR efficiency calculation technique. 2006; http://hdl.handle.net/10204/1479.