CRDS modelling of deuterium release from co-deposited beryllium layers in temperature programmed and laser induced desorption experiments

Deuterium release from Be/D layers co-deposited using high power impulse magnetron sputtering (HiPIMS) is modelled with rate equations using the CRDS code under conditions of temperature programmed (TPD) and laser induced (LID) Desorption experiments. TPD results are simulated to fit D trapping parameters that are in turn applied to simulate the LID. TPD results are compared to equivalent results from JET-ILW and UCSD samples. HiPIMS samples show a different release behavior compared to UCSD and JET samples, release peaks at comparable heating rates are narrower and cannot be modelled using the same set of parameters. With a particular choice of diffusion-trapping parameters that reproduce the TPD peak positions, modelling of the LID efficiency results in a qualitative agreement with experimental observations. In particular, it is shown that a complete outgassing of low D content samples is not possible during laser heating unless the surface temperature exceeds the Be melting threshold.