Comparison of deuterium retention in tungsten exposed to deuterium plasma and gas

Highlights

• D retention in plasma exposure W is much higher than that of gas charging W.

• D₂ desorption temperature of plasma exposure W is lower than that of gas charging W.

• Detrapping energy of D in gas charging W is 2.17 eV.

• Detrapping energy of D in plasma exposure W is 1.04 eV.

Abstract

Deuterium (D) retention behavior in tungsten (W) exposed to D plasma and D₂ gas was studied by means of thermal desorption spectroscopy (TDS): D plasma exposure in which W was exposed to D plasma with 35 eV/D⁺ at 393 K for 0.5 h to the fluence of 3.8 × 10²⁴ D/m²; D₂ gas charging in which W was exposed to D₂ gas of 500 kPa at 773 K for 4 h. TDS shows that the total D retention in plasma exposure W is ~10²² D/m², two orders 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 at the heating rate of 20 K/min. 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 the gas charging W and 1.04 eV for the plasma exposure W, respectively.