He jishu (Jul 2021)
Estimation of total α or total β activities in the test samples with aerosol filter membranes based on HPGe spectrometer
Abstract
BackgroundSichuan Radiation Environmental Management and Monitoring Center participated in the radiation environmental monitoring quality assessment organized by the Ministry of Ecology and Environment in 2020. Two total radioactivity standards prepared by Eckert & Zigler Analytics Corporation were used for test samples in this assessment.PurposeThis study aims to establish an indirect method for the estimation of total α or total β activities in the test samples based on HPGe spectrometer, and to provide some useful references for the application of this method in the analysis of aerosol total radioactivity.MethodsThe low background BE6530 HPGe spectrometer produced by Canberra (US) was used to identify nuclides of test samples and to collect their γ spectra data. Laboratory sourceless calibration software (LabSOCS) was used to calibrate the efficiency of the HPGe spectrometer. A γ-rays standard sample with multiple nuclides in an aerosol filter membrane and a self-made reference sample in an aerosol filter membrane were applied to confirm the reliability of the method established in this work.ResultsA formula is derived for the estimation of total α or total β activities by γ spectra data. The measurement results and uncertainties of total α and total β activities in the two test samples are 61.2 Bq and 73.2 Bq, 6.6% (k=2) and 3.6% (k=2), respectively. The results are all qualified after the Z-score evaluation. In addition, the parameter setting in LabSOCS, background deduction of γ spectra, γ peak selection and γ cascade radiation correction are discussed, which provides a useful reference for the application of this method in the total radioactivity analysis.ConclusionsThe indirect method established in this work has a good accuracy and can be applied in the analysis of aerosol total radioactivity.
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