Effect of Scintillation Cocktail and Quenching Calibration Method on Measurement of 55Fe by LSC

Abstract

In order to optimize the measurement conditions of 55Fe by liquid scintillation counting, the effect of three kinds of commercial scintillation cocktail and two efficiency correction methods on LSC measurements of 55Fe was tested. Configuration of 55Fe samples with the same matrix as after radiochemical treatment for measurement, Ultima Gold AB has the highest sample loading among the three kinds of scintillation cocktail; the counting efficiency of Ultima Gold LLT is the highest and the MDA is the lowest under different miscibility ratios, and the maximum detection efficiency of Ultima Gold LLT is 49.1% when the miscibility ratio is 1∶4, while the MDA is 0.12 Bq. If the sample uses scintillation cocktail different from the quenched standard source, it will have an impact on the accuracy of the results, with an absolute value of maximum average relative deviation is 3.55% between the measured and expected values under experimental conditions. Comparing the two quenching calibration methods of tSIE and TDCR, the TDCR method can eliminate the influence caused by the simultaneous presence of color and chemical quenching on the 55Fe LSC measurement results, and is a more accurate method for measuring 55Fe. The relative deviations between the measured and expected values obtained from the color and chemical quenching calibration curves are -0.35% to 0.40% and -0.91% to -0.16%, respectively, as verified by the spiked samples.

Keywords

• lsc
• 55fe
• scintillation cocktail
• quench
• efficiency calibration