▎ 摘　　要

The ion backflow process has always been a bottleneck for the Time Projection Chambers, and various methods have been developed to suppress this process. Graphene, being the thinnest materials discovered up to now, could be a potential material for completely eliminating the ion backflow, as it is impermeable to atoms, molecules and ions. Thus, ions produced in the Time Projection Chamber are well blocked by the graphene membrane as they are not energetic enough to pass through the graphene membrane in the gas. On the other hand, electrons should be allowed to pass the graphene membrane to generate the electron avalanche. In this paper, transmission coefficient of graphene for eV-scale electrons is studied and a transmission, for 5 eV electrons, to monolayer graphene is shown to be 40%.