Presentation + Paper
13 December 2020 Towards volume manufacturing of high-performance soft x-ray critical-angle transmission gratings
Author Affiliations +
Abstract
High-resolution (R = λ/Δλ >2000) x-ray absorption and emission line spectroscopy in the soft x-ray band is a crucial diagnostic for the exploration of the properties of ubiquitous warm and hot plasmas and their dynamics in the cosmic web, galaxy clusters, galaxy halos, intragalactic space, and star atmospheres. Soft x-ray grating spectroscopy with R > 10,000 has been demonstrated with critical-angle transmission (CAT) gratings. CAT gratings combine the relaxed alignment and temperature tolerances and low mass of transmission gratings with high diffraction efficiency blazed in high orders. They are an enabling technology for the proposed Arcus grating explorer and were selected for the Lynx design reference mission grating spectrometer instrument. Both Arcus and Lynx require the manufacture of hundreds to perhaps ≈ 2000 large-area CAT gratings. We are developing new patterning and fabrication process sequences that are conducive to large-format volume processing on stateof-the-art 200 mm wafer tools. Recent x-ray tests on 200 nm-period gratings patterned using e-beam-written masks and 4x projection lithography in conjunction with silicon pore focusing optics demonstrated R ≈ 104 at 1.49 keV. Extending the grating depth from 4 μm to 6 μm is predicted to lead to significant improvements in diffraction efficiency and is part of our current efforts using a combination of deep reactive-ion etching and wet etching in KOH solution. We describe our recent progress in grating fabrication and report our latest diffraction efficiency and modeling results.
Conference Presentation
© (2020) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Ralf K. Heilmann, Alexander R. Bruccoleri, Jungki Song, Matthew T. Cook, James A. Gregory, Renee D. Lambert, Dimitri A. Shapiro, Douglas J. Young, Miranda Bradshaw, Vadim Burwitz, Gisela D. Hartner, Andreas Langmeier, Randall K. Smith, and Mark L. Schattenburg "Towards volume manufacturing of high-performance soft x-ray critical-angle transmission gratings", Proc. SPIE 11444, Space Telescopes and Instrumentation 2020: Ultraviolet to Gamma Ray, 114441H (13 December 2020); https://doi.org/10.1117/12.2562388
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KEYWORDS
Diffraction gratings

X-rays

Manufacturing

Computed tomography

Diffraction

Spectroscopy

Absorption

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