胶片扫描法对低能X射线标准辐射场的研究

采用胶片剂量计测量了低能X射线辐射装置距X射线光管焦斑不同距离辐射野的大小,得出在距离光管焦斑1 000 mm的参考面辐射野大小及均匀性,并与二维矩阵电离室扫描结果进行了对比。实验结果表明,在距X射线光源焦斑1 000 mm处,在保证直径为100 mm的均匀野的条件下,非均匀性不大于1.5%。在保证非均匀性不大于5%和50%条件下,均匀野大小分别为130 mm和145 mm,满足了低能X射线空气比释动能基准装置量值复现,国际比对和向下量值传递的要求。

Studay on Reference Radiation of Low-energy x-ray With Film Scanning

The size of reference radiation field of low-energy x-ray was measured by film in different position from the tube spot,the diameter of the radiation field and its were obtained in reference plane(1 000 mm from the radiation source) and were compared with the results through two-dimensional ion chamber.The results show that the diameter of the radiation field is 100 mm within 1.5%(1 000 mm from the radiation source).The diamerers of theradiation field are 130 mm and 145 mm within 5% and 50%.These results well meet the requirements of the value repetition of the low-energy X-ray air kerma value standard device,international intercomparison and transfer of quantity values.