X射线空气比释动能(诊断水平)标准装置的建立  

Establishment of X-ray air kerma(diagnostic level)standard device

作　　者：李胤 韦应靖[1,2] 陈双强 方登富 崔伟[1] 冯梅[1] LI Yin;WEI Yingjing;CHEN Shuangqiang;FANG Dengfu;CUI Wei;FENG Mei(China Institute for Radiation Protection,Taiyuan 030006;Tsinghua University,Beijing 100084)

机构地区：[1]中国辐射防护研究院,太原030006 [2]清华大学,北京100084

出　　处：《辐射防护》2021年第S01期133-138,共6页Radiation Protection

摘　　要：为了实现诊断水平X射线剂量率值的准确测量,并开展量值的溯源与传递工作,本文根据IEC 61267—2005标准的要求,建立了管电压40~150 kV、剂量率1.0×10^(-3)~10 Gy/h的X射线空气比释动能(诊断水平)标准装置,实验测量给出了不同辐射质下的辐射场特性,并评定给出了辐射场空气比释动能率的相对扩展不确定度。实验测量结果表明,RQR5辐射质在距离X射线光斑焦点1.0 m处,均匀性>99.0%的辐射野为∅8.0 cm,均匀性>95.0%的辐射野为∅10.0 cm;散射对辐射场的贡献<0.9%;在1.0~5.0 m范围内的距离平方反比律偏差<2.0%;标准电离室测得辐射场剂量率重复性为0.1%。对RQR2~RQR10系列与RQT8~RQT10系列辐射质的半值层和同质系数进行测量,其半值层偏差不超过±0.09 mm,同质系数偏差不超过±0.02。辐射场空气比释动能率的相对扩展不确定度评定结果为U_(rel)=3.8%(k=2)。辐射质特性实验测量结果表明,X射线空气比释动能(诊断水平)标准装置的各项性能指标均满足IEC 61267—2005等标准要求。In order to achieve the accurate measurement of diagnostic level X-ray dose rate value,and to carry out the traceability and transmission of it,this article established a tube voltage of 40-150 kV and dose rate of 1.0×10^(-3)-10 Gy/h X-ray air kernal energy(diagnostic level)standard device according to the requirements IEC 61267—2005 standard,experimental measurement gives out the radiation field characteristics under different radiation qualities,and relative expanded uncertainty of air kernal energy rate in radiation field getting by evaluation.Experimental measurement results show that the radiation quality of RQR 5,while in a distance of 1.0 m from focal point of the X-ray spot,uniformity of radiation field>99.0%is∅8.0 cm,and uniformity>95.0%is∅10.0 cm;the contribution of scattering to radiation field is<0.9%;it is less than 2.0%about inverse square of the distance in the range of 1.0-5.0 m;the repeatability of radiation dose rate measured by the standard ionization chamber is 0.1%.Radiation qualities with RQR2-RQR10 series and RQT8-RQT10 are measured in HVL and homogeneity coefficient,which HVL deviation does not exceed±0.09 mm,and homogeneity coefficient deviation does not exceed±0.02.The evaluation result of relative expanded uncertainty in radiation field air kernal energy rate is U_(rel)=3.8%(k=2).Experimental measurement results of radiation quality characteristics show that the performance indicators of X-ray air kerma(diagnostic level)standard device meet the requirements of standards such as IEC 61267—2005.

关 键 词：诊断水平 空气比释动能率 半值层 均匀性 不确定度 

分 类 号：TL84[核科学技术—核技术及应用]