X射线参考辐射装置固有过滤层厚度的测量  

Measurement and Research of Intrinsic Filtering of X-Ray Optical Machine

作　　者：杭仲斌 刘川凤 刘蕴韬[1] 魏可新[1] 宋明哲[1] 王红玉[1] HANG Zhongbin;LIU Chuanfeng;LIU Yuntao;WEI Kexin;SONG Mingzhe;WANG Hongyu(National Key Laboratory for Metrology and Calibration Techniques,China Institue of Atomic Energy,Beijing 102413,China)

机构地区：[1]中国原子能科学研究院,计量与校准技术重点实验室,北京102413

出　　处：《同位素》2021年第5期433-439,I0001,共8页Journal of Isotopes

摘　　要：固有过滤层厚度是X射线参考辐射装置的重要性能参数之一,需要进行定量测量。本研究以新版本ISO 4037-1标准规范为依据,以N系列辐射质(N-20~N-350)的X射线参考辐射装置为例,通过PTW30013电离室测量不同尺寸次级光阑下的辐射野,建立符合要求的实验环境。结果表明,采用半值层法测量得到该参考辐射装置的固有过滤层厚度为0.122 mm Al;通过增加铝过滤片厚度得出N-40~N-350辐射质下4 mm Al等效固有过滤层厚度;利用单质铝金属和铍金属在不同能量下质能衰减系数的转化关系,得出N-20~N-30辐射质下1 mm铍的等效固有过滤层厚度。本研究结果可为X射线参考辐射装置固有过滤的测量提供一定的参考。The thickness of the inherent filter layer is one of the important performance parameters of the X-ray reference radiation device,and it needs to be quantitatively measured.This research is based on the new version of ISO 4037-1 standard specification,taking N series radiation quality(N-20-N-350)X-ray reference radiation device as an example.Through the PTW30013 ionization chamber,the radiation field under the secondary aperture of different sizes is measured to establish an experimental environment that meets the requirements.The results show that the thickness of the inherent filter layer of the reference radiation device is 0.122 mmAl measured by the half-value layer method;the equivalent inherent filter layer thickness of 4 mm Al under N-40-N-350 radiation quality is obtained by increasing the thickness of the aluminum filter.Using the conversion relationship between the mass-energy absorption coefficient of elemental aluminum metal and beryllium metal at different energies,the equivalent intrinsic filter layer thickness of 1 mm Be under N-20-N-30 radiation quality is obtained.This study provides a certain reference for the measurement of the inherent filtering of the X-ray reference radiation device.

关 键 词：X射线 固有过滤层厚度 半值层法 自由空气电离室 

分 类 号：TL84[核科学技术—核技术及应用] TL82