Experimental determination of the deuterium binding energy with vacancies in tungsten

Deuterium (D) interaction with vacancies in tungsten (W) was studied using thermal desorption spectroscopy (TDS). In order to obtain a TDS spectrum with a prominent peak corresponding to D release from vacancies, a special procedure comprising damaging of a recrystallized W sample by low fluences of 10 keV/D ions, its annealing, and subsequent low-energy ion implantation, was utilized. This experimental sequence was performed several times in series; the only difference was the TDS heating rate that varied in the range of 0.15-4 K/s. The sum of the D binding energy (E-b) with vacancies and the activation energy for D diffusion (E-D) in W was then directly determined from the slope of the Arrhenius-like plot ln(beta/T-m(2)) versus 1/T-m, where beta - heating rate and T-m - position of the respective peak in the TDS spectrum. The determined value of E-b + E-D was 1.56 +/- 0.06 eV. (C) 2016 Elsevier B.V. All rights reserved