Carbon-contaminated mirrors and gratings have been cleaned by a d.c. glow discharge in oxygen. The reflectance of mirrors and the efficiency of gratings were measured in situ before and after cleaning in the photon-energy range 4 ∼ 40 eV or 100 ∼ 1000 eV using reflectrometers which incorporated a discharge electrode. Angle-resolved scattering of mirrors and diffraction patterns of gratings were also measured. The mirror reflectance was restored to that of original mirror materials and the scattering level was reduced rather than increased by the discharge cleaning. The grating efficiency of the inside first order was drastically improved by cleaning, even by nearly an order of magnitude in some energy regions. Furthermore, the effect of a blaze was shown to be recovered by examining changes in the efficiencies of other orders as well.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Mathematical Physics
- Condensed Matter Physics