摘要
为了验证井型电离室对不同能量放射性核素溶液轴向响应及其对放射性活度测量的影响,利用CRC-25R型放射性活度计,将^(125)I、^(131)I、^(18)F、^(137)Cs四种不同能量的放射性核素溶液源在井型电离室内沿中心轴向上移动,测量其放射性活度值的变化,得到轴向位置不同处放射性活度计示值与井型电离室底部的参考示值之比的变化规律,分析轴向响应对不同能量放射性核素放射性活度测量的影响。实验结果表明,不同能量放射性核素溶液其井型电离室轴向响应有明显差异,γ射线能量越高,放射性核素的放射性活度示值极大值的轴向位置越接近井底参考位置;对于γ射线能量较低的^(125)I核素,放射性活度示值极大值的轴向位置接近于井型电离室中部,其示值极大值与参考示值的相对偏差达到了8%,而接近井口处位置时放射性活度计示值与井底参考位置的相对偏差仅-2.9%。
In order to verify axial depth response of different energy radionuclides in well-type ionization chamber and its influence ofradioactive activity measurement,using CRC-25R type calibrator,the change of radioactive activity value of 125I,131I,18F and 137Cs with different energies along the axial position of well ionization chamber was measured.And the change law of the ratio between the measured radioactive activity values at different axial positions and the reference value at the bottom of the well chamber was obtained,the influence of axial position on the measurement of radionuclide activity was analyzed.The experiment results show that the axial response of well ionization chamber is obviously different in different energy nuclide solutions.The nuclidesource with higher theγray energy,the axial position appears the maximum value of radioactivity calibrator is closer to the bottom of well-type ionization chamber.For 125I nuclide with lowγray energy,the axial position of the maximum radioactive activity value is close to the middle of the well chamber,the relative deviation between the measured maximum radioactive activity value and the reference radioactive activity value of 125I was 8%,and the relative deviation between the wellhead disposal radioactive activity value and bottom reference value is only 2.9%。
作者
刘佳煜
赵超
叶东胜
李小双
宋家斑
唐方东
Liu Jiayu;Zhao Chao;Ye Dongsheng;Li Xiaoshuang;Song Jiaban;Tang Fangdong(Shanghai Institute of Metrology and Testing Technology)
出处
《上海计量测试》
2020年第4期25-27,共3页
Shanghai Measurement and Testing
关键词
放射性活度计
井型电离室
轴向距离
核素能量
radioactivity calibrator
well-type ionization chamber
axial distance
nuclide energy
