近玻尔速度Ne^(2+)离子穿过碳膜引起的电子发射

Secondary electron emission from carbon Foils by Ne^(2+) near Bohr velocity

本文测量了入射能为2—25keV/u的Ne2+离子穿过不同厚度碳膜诱导的前向、后向(分别对应出射表面和入射表面)电子发射产额.实验中通过改变炮弹离子的能量,系统的研究了势能沉积、电子能损以及反冲原子对前向、后向电子发射产额的贡献.结果表明,离子的势能沉积只对后向电子发射有贡献,前向、后向电子发射产额分别与Ne2+离子在薄膜出射、入射表面的电子能损近似成正比关系,其中电子能损很低(对应于离子能量很低)的时候,反冲原子对电子发射的贡献不能忽略.

We have measured secondary electron emission yields in forward and backward directions from the carbon foils with different thicknesses, which are penetrated by Ne^2＋ ion of an energy from 2 to 25 keV/u. In the experiment, the contributions of projectile potential energy deposition, electronic energy loss and recoil atom to the forward and backward electron emission yields have been studied systematically by changing the projectile ions energy. Results show that the ions’ potential energy deposition only have the impact on the backward electron emission yield, while the forward and backward electron emission yields increase approximately linearly with the increase of the electron energy loss at the exit and entrance surfaces of the thin film respectively. When the electron energy loss is low, the impact of recoil atoms on the electron emission cannot be neglected.