Tung C J, Baum J W
Safety and Environmental Protection Division, Brookhaven National Laboratory, Upton, New York 11973.
Radiat Res. 1989 Sep;119(3):413-23.
Ionization yields and W-values in several hydrocarbon gases under electron irradiation have been calculated using Inokuti's solution of the Fowler equation, i.e., incorporating a linear dependence of ionization yield on source electron energy. Collision stopping powers of hydrocarbons were evaluated using the Bethe formula with mean excitation energies determined using the additivity rule with modification based on molecular bond strengths. Contributions to the collision stopping powers from discrete level excitations were estimated by multiplying collision stopping powers by the excitation fractions constructed from atomic calculations. Average energy transfers for ionizing collisions producing subionization electrons were calculated using differential ionization cross sections proposed by Khare and co-workers. The calculated W-values are in good agreement with those recommended by ICRU.
利用井出对福勒方程的解，即考虑电离产额对源电子能量的线性依赖关系，计算了几种碳氢化合物气体在电子辐照下的电离产额和W值。采用贝特公式评估碳氢化合物的碰撞阻止本领，其中平均激发能根据加和规则确定，并基于分子键强度进行修正。通过将碰撞阻止本领乘以由原子计算得出的激发分数，估算了离散能级激发对碰撞阻止本领的贡献。利用哈雷及其同事提出的微分电离截面，计算了产生亚电离电子的电离碰撞的平均能量转移。计算得到的W值与国际辐射单位与测量委员会推荐的值吻合良好。
