Liquid Scintillation Analysis for Pure β-Emitter Mixtures by the Method of Least Squares

—Application to Radioassay for Radioactive Waste Solution and Organic Liquid Waste—

Abstract

In radioactivity monitoring, analytical radioassay for nuclides in a monitoring sample is the first choice to be carried out for reasonable countermeasure. The method of least squares has been applied to the radioassay for relatively low-level pure β-emitter mixtures (³H, ¹⁴C, ³²P and ⁴⁵Ca) in radioactive waste solution and organic liquid waste. This liquid scintillation technique can get rid of the difficulty of the analysis for a pure β-emitter mixture in a monitoring sample, and provides fundamental information for subsequent waste-treatment. Detection limit of the four nuclides was estimated to be 0.2 -1.0 Bq/cm³, which is sufficiently low compared with the values for authorized safety guideline.