Computational study for designing high γ protecting layer: Development of a novel γ estimation method based on quantum chemistry

To predict the secondary electron emission coefficient (γ value) for Xe⁺, the reasonable treatment of surface trap levels is required. Then we introduced two characters of surface traps into the computational γ estimation method. The estimated γ values agreed with experimental results quantitatively. A larger number of trapped electrons can increase the γ value because they possess higher energy than valence electrons. Additionally, we suggest that wall charges on protecting layer surface should relate to the trap density and hence γ value.