  Deuterium(D) retention behavior in tungsten(W) exposed to deuterium plasma
and gas was studied by means of thermal desorption spectroscopy (TDS):
deuterium plasma exposure in which W was exposed to D plamsa with 35 eV/D at
393 K to the fluence of 3.8E24 D/m2; D2 gas charging in which W was exposed to
D2 gas of 500 kPa at 773 K for 4 hours. TDS shows that the total D retention in
plasma exposure W is 1.00E22 D/m2, one order of magnitude higher than that of
gas charging W; however, the D2 desorption peak of gas charging W is 952 K,
much higher than 691 K of plasma exposure W. The detrapping energies of
deuterium were determined experimentally from the measured peak temperatures at
different heating rates and were found to be 2.17 eV for gas charging W and
1.04 eV for plasma exposure W, respectively.
