高入射能量下的金属二次电子发射模型

Model of secondary electron emission at high incident electron energy for metal

基于高入射能量电子产生二次电子发射的物理过程,分别对高入射能量电子产生的真二次电子和背散射电子的概率进行理论分析与建模.利用Bethe能量损失模型和内二次电子逸出概率分布,推导出高入射能量电子产生有效真二次电子发射的系数与入射能量的关系式;根据高入射能量电子在材料内部被吸收的规律,推导出高入射能量电子产生背散射电子的系数与入射能量之间的关系式.结合两者得到高入射能量下金属的二次电子发射模型.利用该模型计算得到典型金属材料Au,Ag,Cu,Al的二次电子发射系数,理论计算结果与采用Casino软件模拟金属内部散射过程得到的数值模拟结果相符.

The models of the true secondary electron emission and backscattered electron emission for metal are provided, based on the physical process of secondary electron emission from metal at high incident electron energy. The formula for the true secondary electron yield at high incident electron energy is derived with the Bethe equation known to provide accurate and simple analytical expressions for the stopping power and the probability that a secondary electron produced in a material reaches the surface and is emitted into the vacuum. The formula for the backscattered electron yield at high incident electron energy is derived with the absorbing rule for the incident electron in the material. All the above results lead to a new model for secondary electron emission from metal at high incident electron energy. The secondary electron yields of Au, Ag, Cu and A1 derived with the new model are in good agreement with the results obtained from the scatters process simulation code-Casino.