High reflective mirrors for in-vessel applications in ITER

摘要

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 A1_2O_3 was observed. The test for resistivity to deuterium ion bombardment shows that the exposition to a fluence of ～2 × 10~(20) ions/cm~2 with the ion energy of 40-50 eV results in appearance of blisters on the surface of mirrors covered with Al_2O_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 blistering phenomena is discussed.