摘要
放射性同位素衰变放出热量,衰变热是计算放射性同位素活度的重要依据。为了测量氚的衰变热,本研究对一种μW级别的低检测限微量热计进行检测限测试、工作曲线标定以及含氚样品量热验证。测量结果表明,微量热计的检测限为1.28μW,即38 mCi氚。在165~5063μW(5~150 Ci氚)范围内对微量热计的输出热电势U-输入热功率P进行标定,获得的标定关系式为U(μV)=0.141 P(μW),对应氚活度与输出热电势关系式为A(Ci)=0.213 U(μV),线性相关系数R 2>0.999。含氚样品的重复测量标准偏差为1.14%,与PVT法测量偏差为2.45%。本研究使用的量热计通过水浴与真空环境减小测量环境的波动,保证测量的一致性。标定后的量热计在不破坏氚样品完整性的条件下测量其活度,相比其他氚测量方法更适用于固态氚样品的测量,具有工程应用价值。
Radioactive isotope decay gives off heat,which is an important basis for calculating the activity of radioactive isotope.In order to measure the heat emitted by tritium decay,the detection limit test,working curve calibration and tritium sample measurement verification of a low detection limit microcalorimeter ofμW grade were carried out.The measurement results show that the detection limit of microcalorimeter is 1.28μW,i.e.38 mCi tritium.In this paper,the output thermoelectric potential U-input thermal power P of microcalorimeter was calibrated in the range of 165-5063μW(5-150 Ci tritium),and the calibration relationship obtained is U(μV)=0.141 P(μW),corresponding to the relation between tritium activity and output thermoelectric potential A(Ci)=0.213 U(μV),and the liner correlation coefficient is greater than 0.999.The standard deviation of repeated measurement of tritium samples was 1.14%,and the deviation from PVT method was 2.45%.In order to ensure the consistency of measurement,the calorimeter used in this paper reduces the fluctuation of measurement environment through water bath and vacuum environment.The calibrated calorimeter can measure the activity of tritium samples without damaging their integrity.Compared with other tritium measurement methods,calorimetry is more suitable for the measurement of solid tritium samples and has great engineering application value.
作者
欧阳慧平
袁晓明
何长水
李卓希
张培旭
杨洪广
OUYANG Huiping;YUAN Xiaoming;HE Changshui;LI Zhuoxi;ZHANG Peixu;YANG Hongguang(China Institute of Atomic Energy,Beijing 102413,China)
出处
《同位素》
CAS
2023年第4期440-445,共6页
Journal of Isotopes
基金
CFETR候选氚增殖剂中氚测量技术研究(2017YFE0301605)。
关键词
微量热计
氚活度
检测限
标定
microcalorimeter
tritium activity
detection limit
calibration