48 keV~1.25 MeV X/γ射线空腔电离室研制及性能测试  

Design and Performance Study of the Cavity Ionization Chamber Used in X/γRadiation Field of 48 keV~1.25 MeV

作　　者：刘川凤 成建波[1] 李德红[1] 程金星 黄建微[1] 张晓乐 张健[1] 张璇 李月 郝光辉 LIU Chuan-feng;CHENG Jian-bo;LI De-hong;CHENG Jin-xing;HUANG Jian-wei;ZHANG Xiao-le;ZHANG Jian;ZHANG Xuan;LI Yue;HAO Guang-hui(Division of Ionizing Radiation,National Institute of Metrology,Beijing 100029,China;Unit 96901 of the PLA,Beijing 100096,China)

机构地区：[1]中国计量科学研究院电离辐射计量科学研究所,北京100029 [2]中国人民解放军96901部队,北京100096

出　　处：《计量学报》2023年第12期1889-1896,共8页Acta Metrologica Sinica

基　　金：国家重点研发计划重点专项(2017YFF0206304);中国计量科学研究院基本科研业务费重点领域项目(AKYZD2015-3)。

摘　　要：防护水平电离室广泛应用于核设施、放射治疗和辐射环境监测等剂量率的测量,为了提高防护水平电离室的国产化水平,设计了测量防护水平剂量率的空腔电离室。通过理论计算、蒙特卡罗模拟对电离室的室壁厚和保护极进行研究。在不同能量辐射场中对电离室性能进行测试,测试结果表明:电离室漏电流绝对值小于5 fA,工作坪区为200~800 V。在N60~N250的X辐射场和^(137)Cs、^(60)Coγ辐射场中对电离室的能量响应进行测试,当剂量率归一化到^(60)Co时,电离室能量响应相对偏差在±5%之内,电离室在半年内的长期稳定性和角响应都优于0.5%。所述电离室能够实现3 mGy/h~30 Gy/h剂量率的测量,且与约定剂量率相对偏差优于±5%。The ionization chamber is widely used for the dosimetric measurement on the protection level dose rate in nuclear facilities,radiation therapy,and environmental monitoring.In order to improve the domestic manufacturing level of the ionization chamber,the cavity ionization chamber was studied.The thickness of the ionization chamber wall and the design of the guard electrode were studied by the method of theoretical analysis and Monte Carlo simulation.The designed cavity ionization chamber was tested in the standard X andγradiation field to evaluate the dosimetry characteristic.The results showed that the leakage current was less than±5 fA,and the work voltage of the cavity ionization chamber was 200~800 V.The energy response was tested in the N60~N250 X radiation field and the^(137)Cs,60 Coγradiation filed.When the dose rate is normalized to^(60)Co radiation field,the energy response was better than±5%.The long-term stability and the angular response of the ionization chamber in half a year was better than 0.5%.At last,it can realize the measurement of dose rate of 3 mGy/h~30Gy/h with the relative deviation for the agreed dose rate better than±5%.

关 键 词：防护水平剂量率 空腔电离室 能量响应 漏电流 蒙特卡罗模拟 

分 类 号：TB98[一般工业技术—计量学]