Author: Du, J.
Paper Title Page
TUPYP026 Influence of the Groove Curvature on the Spectral Resolution in a Varied-Line-Spacing Plane Grating Monochromator (VLS-PGM) 67
 
  • J. Du, X.W. Du, Q.P. Wang, Z. Wang
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
 
  Diffraction-limited synchrotron radiation (DLSR) light source with smaller source size and emittance makes ultra-high spectral resolution beamline possible. Here, we report an undulator-based beamline optical design with ultra-high spectral resolution using a varied-line-spacing plane grating monochromator (VLS-PGM), which is a well-proven design for achieving ultra-high resolution in the soft X-ray band. A VLS plane grating with a central groove density of 2400 l/mm is utilized to cover the photon energy region of 250 ~ 2000eV. VLS gratings are generally fabricated using the holographic method, but the resulting grating grooves are two-dimensionally curved curves, which can affect the resolution of the monochromator. To analyse this effect, we first use a spherical wavefront and an aspherical wavefront to generate the fringes and optimized the recording parameters. We also present a method for calculating the groove curvature of holographic plane VLS grating grooves. Furthermore, the influence of grating groove curvature on beamline resolution is theoretically analysed based on the aberration theory of concave grating.  
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DOI • reference for this paper ※ doi:10.18429/JACoW-MEDSI2023-TUPYP026  
About • Received ※ 25 October 2023 — Revised ※ 03 November 2023 — Accepted ※ 04 November 2023 — Issued ※ 12 March 2024
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