Study of hydrogen isotopes behavior in carbon based materials with in situ ion beam analysis under plasma exposure

Abstract Deuterium retention in isotropic graphite (ETU-10) was investigated by using nuclear reaction analysis (NRA) under high flux steady state plasma exposure, relevant to divertor plasma conditions. The sample temperature was controlled precisely from 350 K to 550 K with a step of 50 K by using air cooling and electron heating. The sample was irradiated by deuterium plasma at three different fluxes up to 1.0 × 10 18 cm −2 s −1 with the incident ion energy of 33 eV. As the result, dynamic retention was clearly observed. The dynamic retention decreased with the sample temperature and increased with the plasma flux (at the flux of 1.0 × 10 18 cm −2 s −1 , dynamic retention was 8.8 × 10 16 cm −2 at 350 K and 3.5 × 10 16 cm −2 at 550 K). However, a fraction of the dynamic retention normalized by total retention for each sample temperature remained constant. Furthermore, the sample temperature dependence of release time was observed (48–84 ms).