Effects of argon on deuterium retention in polycrystalline tungsten under single, sequential and simultaneous ion irradiation

Abstract

Argon is one of the candidates for impurity seeding in the ITER divertor; however, few studies exist on either Ar retention in W, or its effect on D retention in W. The current study investigates the effects of simultaneous (SIM) and sequential (SEQ) irradiation of D-2.5% Ar on polycrystalline tungsten at 300–700 K, with ion energies of 500 eV/D+ and 1.5 keV/Ar+, and compares the findings with a similar previous study on D+/Ne+ irradiation; Ne being another impurity seeding candidate. Trapped D and Ar in irradiated specimens is measured using thermal desorption spectroscopy (TDS). Ar is found to be similar to Ne in its effectiveness in reducing D retention in W, both performing somewhat better than He at reducing D retention at higher W temperatures.