Solute diffusion of hydrogen isotopes in tungsten—a gas loading experiment

The diffusion of protium and deuterium in tungsten is measured in gas loading experiments as a function of temperature for a hydrogen isotope loading pressure of 500 mbar and temperatures between 1600 K and 2600 K. The diffusion parameters are measured from the degassing rates of both a single-crystalline and a polycrystalline tungsten cylinder by mass spectrometry. The data are analysed assuming an Arrhenius-like temperature dependence of the diffusivity and following the classical analysis approach of Frauenfelder (1969 J. Vac Sci. Technol. 6, 388). For deuterium in tungsten an activation energy of $E_A^D=0.28\pm$ 0.06 eV is obtained. For protium the activation energy is identical within the uncertainty limits. (topical issue article)