便携式γ谱仪对^137Cs、^131I液样探测效率的刻度

Detection Efficiency Calibration of PortableγSpectrometer for ^(137)Cs and ^(131)I Solution Samples

便携式γ谱仪主要用于主冷却剂水样中典型核素的现场辅助识别及其活度浓度的测量分析。为确定典型核素特征峰净面积和水样中该核素活度浓度的关系,必须进行源峰效率刻度。本文通过测量133Ba、137 Cs、60 Co 3种核素的混合溶液得到效率刻度曲线,然后对不同活度浓度的137 Cs标准溶液、131I标准模拟溶液进行测量。结果表明,谱仪均能正确识别137 Cs、131I核素,活度浓度测量的相对误差均<10%,初步满足元件破损监测精度和灵敏度的需求。

The portableγspectrometer can be used for identification of typical nuclides in the primary coolant and acquiring their activity concentrations in situ.The sourcepeak efficiency should be calibrated to ascertain the relationship between the net area under the characteristic peak of typical nuclide and its genuine activity concentration in the water sample.The efficiency calibration curve was acquired by measuring the mixed solution of 133 Ba,137 Cs and 60 Co nuclides,and then 137 Cs standard liquid and simulated131 I standard liquid were measured respectively.Test results indicate that the spectrometer can identify typical nuclides 137 Cs and 131 I,and the measuring relative error of activity concentration is less than 10%,which satisfies the requirement of measurement accuracy and sensitivity for fuel element rupture detection.