Simulation study on retention and reflection from tungsten carbide under high fluence of helium ions

We have studied, with a Monte Carlo simulation code ACAT-DIFFUSE, the fluence-dependence of the amount of helium atoms retained in tungsten carbide at room temperature under helium ion bombardment. The retention behavior may be understood qualitatively in terms of irradiation-dependent diffusion coefficient assumed and range. The re-emission, reflection and sputtering from tungsten carbide under helium ion irradiation were derived and compared with each other. We have discussed the retention curves for incident energy of 5 keV at incident angles of 0 deg. and 80 deg. and of 500 eV at 0 deg. The energy spectra of helium atoms reflected from tungsten carbide for incident energy of 500 eV at 0 deg. and 80 deg. were compared with those from graphite and tungsten