基于反宇宙射线γ谱仪的水样品测量

摘要/Abstract

摘要： 本文基于本底水平较低的反宇宙射线γ谱仪,对其在水样品测量上的应用进行了探讨。文中使用水标准源对反宇宙射线γ谱仪进行效率刻度,比较不同形状水样品探测效率差异,对采集的某水样品经蒸发浓缩后测量,比较反宇宙γ谱仪与其他γ谱仪测量水样品的探测限。结果γ射线能量E＜130 keV时,反宇宙γ谱仪对马林杯($\phi$17 cm×17 cm)水样品的探测效率低于圆柱体($\phi$7.5 cm×7.0 cm)水样品,而E＞130 keV时,马林杯水样品的探测效率明显大于圆柱体样品。反宇宙γ谱仪测量马林杯水样品的探测限比圆柱体水样品探测限低一个数量级。反宇宙γ谱仪对同一水样品的探测限比常规高纯锗谱仪低一个数量级,该反宇宙γ谱仪直接测量未经前处理马林杯水样品中核素¹⁴⁴Ce、¹³⁷Cs和⁶⁰Co的探测限分别为3.07×10^-2 Bq/L、3.67×10^-3 Bq/L、3.70×10^-3 Bq/L。结论是反宇宙射线γ谱仪可用于低水平放射性水样品测量,其优势在于减少前处理时间,缩短样品测量周期,大大降低探测限,提高测量精确度。

关键词: 反宇宙射线γ谱仪, 反符合, 水样品测量

Abstract: This article discuses the application of anti-cosmic ray γ spectrometer with low background level on water sample measurement. In this paper, a water standard source is used to efficiency calibration, and the difference of detection efficiency of water samples of different shapes is compared. The detection limit of the water samples measured by the anti-cosmic ray γ spectrometer is compared with other gamma spectrometers. Results when γ energy E<130 keV, the detection efficiency of marlin cup ($\phi$ 17 cm×H17 cm) is lower than the cylinder ($\phi$7.0 cm×7.5 cm) for water samples. When E>130 keV, the detection efficiency of marlin cup is higher than the cylinder sample. The detection limit of marlin cup measured by anti-cosmic γ spectrometer was one magnitude lower than that of cylinder water samples. The detection limit of the anti-cosmic γ spectrometer for the same water sample is one magnitude lower than that of the common γ spectrometer. The detection limit of radionuclides such as ¹⁴⁴Ce, ¹³⁷Cs and ⁶⁰Co in the samples of marlin cup water without pretreatment is 3.07×10^-2 Bq/L, 3.67×10^-3 Bq/L and 3.7×10^-3 Bq/L, directly measured by anti-cosmic γ spectrometer. Conclusion the anti-cosmic γ spectrometer can be used for the measurement of water samples with low radioactivity. Its advantage is that it can reduce pretreatment time, shorten sample measurement cycle, greatly reduce detection limit and improve measurement accuracy.

Key words: anti-cosmic ray γ spectrometer, anti-coincidence, water sample measurement

中图分类号:

TL817

刘庆云, 马国学, 胡翔. 基于反宇宙射线γ谱仪的水样品测量[J]. 辐射防护, 2020, 40(5): 408-413.

LIU Qingyun, MA Guoxue, HU Xiang. Measurement of water sample based on anti-cosmic ray γ spectrometer[J]. RADIATION PROTECTION, 2020, 40(5): 408-413.

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