Deuterium retention behavior of pure and Y2O3-doped tungsten investigated by nuclear reaction analysis and thermal desorption spectroscopy

Abstract

Pure and Y2O3-doped tungsten samples were simultaneously exposed to deuterium (D) plasma. The following exposure parameters were investigated: ion energy of 38 eV/D, sample temperatures of 370, 450 and 570 K, and incident fluences of 6 × 1024 and 7.5 × 1025 D/m2. The deuterium retention behavior of these tungsten materials was investigated by nuclear reaction analysis and thermal desorption spectroscopy. After exposure at 450 K Y2O3-doped tungsten shows a D depth profile comparable with that of pure tungsten. But at each investigated exposure condition Y2O3-doped tungsten shows a higher total D inventory than pure tungsten. This is attributed to the presence of intrinsic defects with high trapping energies. Investigation of the D retention behavior of four different Y2O3-doped tungsten materials, which contain the same amount of Y2O3, but have various microstructures, suggests that sub-micron pores are the underlying intrinsic defects responsible for the appearance of a high temperature D release peak. Keywords: Tungsten, Tungsten alloys, Deuterium retention, Plasma-surface interaction, Morphology, Thermal desorption spectroscopy