水氡仪器标定异常原因浅析

2008年8月福建省地震局水化学中心实验站对新购置的水氡仪器进行标定，标定结果出现异常：全部闪烁室K值超出《地震水文地球化学观测技术规范》所要求的取值范围，但每个闪烁室多次标定的K值的相对偏差基本小于5％，说明虽然K值超出要求，但是固体氡气源装置上标称氡射气剂量分配值是稳定的。造成标定结果异常的可能原因主要有，标定过程出现漏气，新仪器选择的各项指标有误，固体氡气源故障。更换干燥剂、橡皮管，检查每一个接口，以及闪烁室的密封性能和真空泵的抽真空性能，重新检查仪器状态均已正常后，用现用的两套仪器进行标定，以检验是否因新仪器选择的各项指标有误造成标定结果异常。两次标定结果类似，分析认为，可能是固体氡气源故障，虽然在这次标定中，固体氡气源装置上标称氡射气剂量分配值是稳定的，但可能其含量较以前发生了变化。

Explanation of the abnormal in calibrating water radon instrument

In August 2008, Hydrochemistry Center Experiment Station of Earthquake Administration of FuJian Province calibrates water radon instrument which is newly purchased. The result is abnormal： All K value of scintillation chamber is out of range in criterion. But in each scintillation chamber repeated calibration,the relative deviation of K values is less than 5%. It can be expressed as that K values exceed requirements, but it is stable to the assign value to dosage of radon emanation in device. The main results of abnormal calibration may be due to gas leakage in calibrating, mistake choosing of the parameter for new instrument and fault of solid radon source. After replacing the desiccant and rubber tube, checking sealing performance in each interface and scintillation chamber and checking capability of vacuum pump, the calibration was repeated with two instruments for test whether the improper choice of indicators for new equipment calibration causes the abnormal results. Because of similar results, We analyze that it may be caused by the fault of the solid radon source. The assign value to dosage of radon emanation is stable in the calibration of solid radon source device, but its content may be changed than before.