同位素2026，Vol.39Issue(4)：315-321,7.DOI:10.7538/tws.2026.youxian.048
239Pu活度绝对测量方法研究
Research on the Absolute Activity Measurement Method for 239Pu
胡涵佳 1徐利军 1罗明杰 1夏文 1朱保吉 1姚顺和 1罗瑞1
作者信息
- 1. 中国原子能科学研究院,北京 102413
- 折叠
摘要
Abstract
To achieve the absolute measurement of 239Pu activity,a method combining inductively coupled plasma mass spectrometry(ICP-MS)with liquid scintillation counting(LSC)was proposed.The total α activity of the sample was measured using the triple-to-double coincidence ratio(TDCR)mode of a liquid scintillation counter,and the atomic ratio of 239Pu to 240Pu was determined by ICP-MS.The activity of 239Pu was then calculated using the decay constants.The nitric acid concentration for sample dilution was optimized to be 0.6-0.8 mol·L-1 to suppress quenching and adsorption.The pulse level index(PLI)was set to 14.A plutonium solution was measured,and the repeatability of the total α specific activity measurement was 0.49%,remaining stable over a seven-day observation period.The specific activity of 239Pu was 184.47 Bq/g,accounting for 93.11%of the total α activity.The relative expanded uncertainty of the measurement was 1.4%(k=2),with major contributions from the sample weighing,coincidence resolving time,and isotopic ratio measurement.This method does not require standard solutions for efficiency calibration and is essentially an absolute measurement.The applicability of this method to simple plutonium solutions has been validated,providing metrological technical support for nuclear material accounting and nuclear safeguards.关键词
239Pu/活度绝对测量方法/液体闪烁计数法/脉冲形状甄别Key words
239Pu/absolute activity measurement/liquid scintillation counting/pulse shape discrimination分类
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胡涵佳,徐利军,罗明杰,夏文,朱保吉,姚顺和,罗瑞..239Pu活度绝对测量方法研究[J].同位素,2026,39(4):315-321,7.
