Ion fluence and energy effects on the optical properties of SS mirrors bombarded by hydrogen ions

摘要

The effects of hydrogen ion (W) bombardment on the optical properties of polycrystal stainless steel (S) Mirrors were investigated. Ellipsometry. profilometry, scanning electron microscopy, angle distribution of scattered light. and spectral reflectance were used to characterize the surfaces. Results for the bombardment of SS mirrors with ions of fixed energy (0.3, 0.65 and 1.5 keV/H), with ion flux density (0.5-2)(.)10(20) H/m(2)s up to fluences of (1.1-4.3)(.)10(24) H/m(2) are presented. The data show that the surface roughness rises with both increasing ion energy and ion fluence, and that surface roughening leads to an increase of the scattered light with a corresponding decrease of reflectance at normal incidence. The thickness of the apparent layer, obtained by ellipsometry, was found to rise with increasing ion energy at fixed ion fluence and with increasing ion fluence at fixed ion energy. Possible mechanisms for the ion energy effect on the degradation rate of stainless steel mirrors and the origin of the apparent layer are discussed. [References: 8]