Material properties of co-deposition formed on plasma facing materials in all-metal machine TRIAM-1M

To examine re-deposition of impurities on the plasma facing walls, material exposing experiments were carried out in TRIAM-1M under-long plus discharges. The exposed specimens and simulate specimens, which was made by physical vapor deposition in a low pressure oxygen atmosphere, were analyzed by means of X-ray photoelectron spectroscopy and thermal desorption spectroscopy. The deposition was composed mainly of Mo and O, and contained C and components of the vacuum vessel (304SS) slightly. The chemical state of deposited Mo was mixture of metal and oxide, and agrees with the one of simulate specimen implanted with deuterium ions, quantitatively. These results indicate that the co-deposited hydrogen and oxygen, affect the physicochemical properties of the depositions in TRIAM-1M. The retention properties of hydrogen isotope could be changed largely even if the least amount of deposition is formed on the surface.