胶片扫描法对低能X射线标准辐射场的研究

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

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。

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 nun 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 intereomparison and transfer of quantity values.