电子直线加速器焦点测量

Focus measurement of electron linear accelerator

针对三明治法测量直线加速器焦点,目视底片判读存在测量结果主观因素影响较大的不足,提出了胶片扫描与图像分析相结合的量化测量方案。通过分析试验数据,提出用二次多项式拟合消除加速器辐射场不均匀性对测量结果的影响,以及用半高宽测量代替半峰高条纹统计的改进三明治焦点测量方法。实测表明:得到的焦点测量结果一致性更好,能更加准确地反映焦点尺寸的较小差异。

Many personal factors would influence the result of the focus measurement of linear accelerator using the conventional sandwich method. This paper presents a modified method which applies a film scanning meter to scan the X-ray image film got by sandwich method for obtaining a greyscale distribution, then the full width at half maximum value of greyscale distribution represents the focus size. The method can eliminates disadvantage influence from accelerator radiant field asymmetry by quadratic polynomial fitting and measures peak width at half height instead of stripe statistic.