Experimental determination of the deuterium binding energy with vacancies in tungsten

Abstract

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 (Eb) with vacancies and the activation energy for D diffusion (ED) in W was then directly determined from the slope of the Arrhenius-like plot ln(β/Tm2) versus 1/Tm, where β – heating rate and Tm – position of the respective peak in the TDS spectrum. The determined value of Eb + ED was 1.56 ± 0.06 eV.