Surface modification and deuterium retention in tungsten and molybdenum exposed to low-energy, high flux deuterium plasmas

Alimov, V.; Shu, Wataru; Roth, J.*; Komarov, D. A.*; Lindig, S.*; Isobe, Kanetsugu; Nakamura, Hirofumi; Yamanishi, Toshihiko

This work deals with deuterium retention in single-crystalline and polycrystalline W and Mo exposed to low-energy (38-200 eV/D) and high ion flux deuterium plasmas at temperatures in the range from 303 to 783 K. The D retention and depth profiles were examined with thermal desorption spectroscopy (TDS) and the nuclear reaction. The surface morphology of the plasma-exposed W and Mo samples was investigated by scanning electron microscope. In W and Mo single-crystalline and polycrystalline materials exposed to the 38 and 200 eV D plasmas to ion fluences, in the range from 2E24 to 1E26 D/m, the D retention increases with the exposure and then decreases as the temperature grows further. For polycrystalline samples exposed at temperatures above 350 K, the D retention in the bulk (far beyond the ion range) is dominant.