The photon spectrum data that are used in the calculation for translating the absorbed dose to the photon fluence have been obtained by the experimental method with a 12mv pulse accelerator and the iterative least - squares data analysis technique 为此,利用穿透系数数值分析的叠代最小二乘法对12mv脉冲加速器的轫致辐射谱进行了实验测定,并在同样的几何条件下,用m - c方法对其进行了计算。