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 0.06 eV is obtained. For protium the activation energy is identical within the uncertainty limits.