Sketch of the optical path of the soft x-ray spectrometer with source S. The aperture A can be used to mask the spherical mirror M. G denotes a blazed VLS grating, and D a back-illuminated CCD detector in normal incidence geometry.
The different limitations (see inset) of the resolving power as a function of photon energy and diffraction order. For calculating the aberration limit, a fully illuminated mirror (i.e., with open aperture A) was assumed.
Comparison of the measured (squares) and calculated (triangles) grating efficiencies for the four photon energies of interest in their respective diffraction orders. The efficiencies were measured at beamline 6.3.2. For the calculations a microroughness of 10 Å was assumed.
The narrow Rayleigh line as it appears on the rotated CCD detector, allowing the use of the super-resolution technique. The image is binned to 64 slices in the vertical direction and expanded by a factor of 100 in the horizontal direction.
(a) The four top spectra (dashed) show the sums of four groups of slices selected and shifted by their subpixel shifts. The bottom spectrum is the sum of the four spectra above. (b) The solid line with circles is a copy of the lowest spectrum in (a), the black bars represent the response function of the super-resolution technique to a -function, and the dashed line with rectangles shows the spectrum deconvolved by the response function using three van Cittert iterations.
Resonant inelastic soft x-ray scattering (RIXS) map of HOPG. The arrows denote areas of the map with predominant and emissions, as well as - and -excitations. The Fermi level is marked on both axes.
Optical parameters as well as calculated reflectivities and efficiencies for the selected photon energies and diffraction orders. The total detection efficiency is calculated as the product of calculated mirror reflectivity, measured grating efficiency, and detector efficiency taken from the operating manual of the detector (Ref. 38).
Article metrics loading...
Full text loading...