X-UV Optics in near-normal incidence realised at the "Institut d'Optique"

Abstract

Two objectives to be used at 304 A, in near-normal incidence have been made at IOTA : one is Ritchey-Chretien Telescope, the other is a Schwarzschild microscope used to observe laser heated targets. They are both made from two spherical surfaces shaped with an accuracy of λ/10, and covered by Si/Re-Wmultilayers. For the Ritchey- Chretien, the surfaces were aspherized by vacuum deposition before coating. Multilayer period and interface roughness were evaluated by using X-ray reflectanetry during the deposition process and grazing incidence X-ray reflectometry after the multilayer coating. A 7 A rms roughness for Si, 10 AA for W-Re, and a reflectivity of 10% were evaluated for each telescope mirror. For minimazing aberrations, the two mirrors of the Schwarzschild microscope were very accurateley centered. Results shows a resolution better than 4 gm for this instrument at the 304 A wavelenght used.