Sputtering Yields of Beryllium and Tungsten by Various Atoms from Hydrogen to Tungsten

Sputtering yields of targets made of Be and W, promising materials for the first wall and the divertor of the ITER tokamak, are calculated in a wide range of projectile energies from 10 to 100 000 eV by computer simulation. The following atoms were chosen as bombarding particles: H, D, T, He, Be, C, N, O, Ne, Ar, and W. It is demonstrated that the shape of the surface strongly impacts the obtained results. The limiting cases of a planar potential barrier (a smooth surface) and a spherical potential barrier (a rough surface) are analyzed. The data on the average energy and angular distribution of sputtered atoms needed for calculation of the impurity influx into tokamak plasma are obtained. The influx of atoms of the wall material into the ITER tokamak plasma upon wall sputtering by fluxes of fast deuterium and tritium atoms leaving plasma is estimated.