Variable radius X-ray mirror

The mirror is integrated inside a mechanical bender for continuous adjustment of the radius of curvature in the meridional direction between 20 km convex and 11 km concave. The mirror is composed of 3 regions:

  • a central region with a cylindrical shape in the sagittal direction (acts as a toroidal mirror, if bent to the appropriate radius) ;


  • 2 outer flat regions. For R = Infinity


    The variable radius in the meridional plane allows the optional utilisation of additional collimating and focusing elements in the same plane. At present, there is a collimating refractive compound lens (CRL), made out of Beryllium, installed at 28.5 m from the source point in OH1. The purpose of this lens is to better match the spectral angular acceptance of the high-heatload silicon (1 1 1) and the postmonochromator, as well as to keep the vertical size of the X-ray beam as small as possible so that a focusing CRL can be effectively used (demagnifiaction M 1:11 with p=94 m and q=8 m).


    1.        Mirror description


    Mirror name: MRX 64 M2 (engraved on mirror side)
    Mirror dimensions (LxWxT) : 1200x118x80 mm 3
    Material : Silicon
    Coating : Pt (600Å)
    Shape U-BENDER
    Supplier : SESO



    Optical surface: 800x20 mm2
    Surface roughness : < 3 Å rms over 1.3 mm x 100Mum
    Meridional Slope error: on 800mm < 1.2 Murad rms (see below)
    Meridional Radius: -20 km up to 11 km
    Sagittal radius: 101.9mm ± 0.2mm
    Reflectivity: 83 – 76%
    Focal size: 280 x 60 Mum (hor. x vert.; FWHM)



    variable radius xray


    View of the variable radius X-ray mirror on the hexapode table