多晶体二次电子的角度分布

Angular distribution of secondary electron emitted from polycrystalline surfaces

根据二次电子发射的主要物理过程,推导了内二次电子到达多晶表面并逸出的几率的角度分布、斜射入多晶的高能原电子产生的二次电子的角度分布和由背散射电子产生的二次电子的角度分布。同时,推导了高能原电子轰击多晶产生的二次电子的角度分布公式,该公式表明多晶的二次电子遵循余弦分布,且与原电子的入射角无关。分析结果表明:在内二次电子最大逸出深度范围内,如果由射入多晶的原电子和背散射电子产生的内二次电子数是常数,则多晶的二次电子的角度分布遵循余弦分布;如果由射入多晶的原电子和背散射电子产生的内二次电子数越来越少,则多晶的二次电子发射角度分布随出射角减少得比出射角的余弦值更慢;如果由射入多晶的原电子和背散射电子产生的内二次电子越来越多,则多晶的二次电子发射角度分布随出射角减少得比出射角的余弦值更快。

Based on main physical processes of secondary electron emission,the probability of secondary electron reaching the surface and emitting into vacuum at emission angles θ was deduced;the angular distribution of secondary electron released per primary electron entering polycrystalline obliquely was deduced,and the angular distribution of secondary electron released per backscattered electron was deduced.The angular distribution of secondary electron emitted from polycrystalline surfaces is formulated as cosinoidal and independent of the incidence angle of the primary electron at high electron energy.It is concluded that the angular distribution of the secondary electron follow of the simple cosine distribution as the number of secondary electrons excited by primary electron and backscattered electron within the maximum escape depth of secondary electron from polycrystalline is a constant;the angular distribution of secondary electron emitted from polycrystalline surfaces decreases more slowly than cosθ as the number of the excited secondary electron within the maximum escape depth becomes less and less;however,it decreases more rapidly than cosθ as the excited secondary electron becomes more and more.