Dynamic Monte-Carlo modeling of hydrogen isotope diffusion in co-deposited layers

Reactive–diffusive transport of hydrogen in the porous, three-dimensional structure of co-deposited films is simulated using a kinetic Monte Carlo (KMC) method. The simulations are carried out on samples generated from the film growth Monte Carlo (FGMC) code which simulates the film-growth process in remote regions of fusion devices. It is seen that the steric repulsion between the incoming hydrocarbon and the surface atoms is an important parameter which affects the structure and trap concentrations of these soft films. Initial results indicate that diffusion of hydrogen through pores in the co-deposited films could be a major contributor to the high density of hydrogen in co-deposits seen at remote locations of fusion devices.