High reflective mirrors for in-vessel applications in ITER

Abstract The structure and surface morphology of aluminum and silver mirrors covered with protective dielectric oxide layer were studied by means of TEM and SEM. The presence of needle-like pores throughout the thickness of the ZrO 2 film and bubble-like pores in Al 2 O 3 was observed. The test for resistivity to deuterium ion bombardment shows that the exposition to a fluenceof ∼2×10 20 ions/cm 2 with the ion energy of 40–50 eV results in appearance of blisterson the surface of mirrors covered with Al 2 O 3 . For the mirrors protected with ZrO 2 no noticeable changes in surface morphology and reflectivity were found even after order of magnitude higher ion fluence. The effect of different porous structures on blisteringphenomena is discussed.