质子剂量的解析计算

Analytical calculations of proton dose

计算了质子束垂直入射于水中的剂量分布。首先给出宽束入射时的剂量深度曲线；然后以一高斯函数描述多重散射作用，得到了三维剂量分布的积分公式。最后给出了入射粒子束为均匀圆柱时剂量分布离轴比的级数表达式。结果表明，给出的部分计算结果与ＰＴＲＡＮ的结果和实验结果符合较好。

Dose distribution in water is calculated for normal incidence of proton beams.The depth-dose relation of broad beams is presented, and a 3-D dose distribution with a radial Gaussian representing multiple scattering of pencil beams is then obtained. A series form of dose off-axis-ratio(OAR) for cylindrical homogeneous beams is finally presented.