便携式γ谱仪对137Cs、131I液样探测效率的刻度

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、¹³⁷Cs、⁶⁰Co 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¹³⁷Cs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¹³⁷Cs、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。

Detection Efficiency Calibration of Portable γ Spectrometer for 137Cs and 131I Solution Samples

The portable γ spectrometer can be used for identification of typical nuclides in the primary coolant and acquiring their activity concentrations in situ. The source-peak 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 ¹³³Ba, ¹³⁷Cs and ⁶⁰Co nuclides, and then ¹³⁷Cs standard liquid and simulated ¹³¹I standard liquid were measured respectively. Test results indicate that the spectrometer can identify typical nuclides ¹³⁷Cs and ¹³¹I, 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.