近程碰撞对He^+离子诱发背向电子发射贡献比例的计算

Evaluation of the contribution fraction of close collision to the backward electron emission induced by He^+ ion

用Monte Carlo方法模拟了高速He+ 离子入射到C ,Cu和Al固体表面所诱发的电子发射 .用这个程序计算了背向的电子发射产额 ,并且同时计算了近程碰撞对总的背向电子发射产额的贡献比例 ,对C ,Cu和Al其值分别是0 5 ,0 5 5和 0 .42 .对在近程碰撞中产生的高能δ电子 (E >10OeV)对背向电子发射行为的影响也进行了详尽地讨论 ,只有那些能量为几百个eV的δ电子对产额的贡献比例较大 .对于C靶 ,δ电子对电子阻止本领最大值附近的二次电子发射行为会产生影响 .

Electron emission for He+ incident on solid surfaces of C, Cu and Al was simulated with the Monte-Carlo method. The backward electron emission yields are calculated. The contribution fraction of electrons emitted by close collision to the total backward emission yield is evaluated with this code, and contribution fraction is 0.5, 0.55 and 0.42 for C, Cu and Al, respectively. The effect of high-energy (E > 100eV) delta electrons on the backward electron yield is also considered in detail, and only those delta electrons with an energy of a few hundred eV plays an important role in the backward electron emission. For C, delta electrons will affect the behaviour of electron emission yield near the maximum electronic stopping power. Results of yield obtained are compared with experimental data of other authors, and a good agreement is found.