Author/Authors :
Bardamid، نويسنده , , A.F and Belyaeva، نويسنده , , A.I. and Davis، نويسنده , , J.W. and Dobrotvorskaya، نويسنده , , M.V. and Galuza، نويسنده , , A.A. and Kapit?nchuk، نويسنده , , L.M. and Konovalov، نويسنده , , V.G and Ryzhkov، نويسنده , , I.V. and Shtan’، نويسنده , , A.F. and Slatin، نويسنده , , K.A. and Solodovchenko، نويسنده , , S.I. and Voitsenya، نويسنده , , V.S.، نويسنده ,
Abstract :
The ion-induced modification of aluminum alloy mirrors, under bombardment by deuterium plasma ions has been investigated as a simulation of the environment effects on in-vessel mirrors in ITER. Ellipsometry and reflectrometry have been used to characterize the mirror surface, along with several surface diagnostic techniques (XPS, Auger, SIMS). The results of multiangular- and spectro-ellipsometry were analyzed using both a bare surface model, and effective medium model; the medium was composed of Al, Al2O3 (Al(OD)3 or AlOOD), and voids. It was found that the reflectance decreases following exposure to keV-range ions, but can be restored by subsequent exposing the mirror to low-energy ions (∼60 eV). Chemical processes related to an increased oxide layer are thought to be responsible for the decrease in reflectance, while the reduction of the oxide layer following low-energy D+ exposure may lead to the return of high reflectance. By comparing the measurements with the results of modeling, a mechanism is suggested to explain the experimental data. The mechanism is based on: (1) chemical processes in a surface layer and (2) сhanges in the thickness and roughness of the surface layer.
