English

Lynx grating spectrometer design: Optimizing chirped transmission gratings

Instrumentation and Methods for Astrophysics 2023-12-05 v1

Abstract

Lynx is one of four large-mission concept studies for NASA's 2020 Decadal survey. The design reference mission includes an X-ray grating spectrometer (XGS) based on critical-angle transmission (CAT) gratings. In the past we studied different grating sizes and arrangements using traditional flat CAT gratings with constant bar spacing. However, new technology development brings chirped gratings in reach. Using chirped gratings where the grating bar spacing varies over a grating allows us to fill the aperture with larger gratings because the chirp can compensate for some aberrations caused by the deviation of large flat gratings from the Rowland torus. This reduces the area blocked by grating support structures. Using larger gratings also carries potential cost savings. We use ray-tracing to study an XGS design with chirped grating and find that using chirped gratings of 8016080 * 160 mm size allows us to reduce the number of gratings from a few thousand to a few hundred, while simultaneously increasing the effective area by 25% and keeping the resolving power constant. Bending those gratings to maintain a constant blaze angle over the entire grating increases the effective area by another 5-10%.

Keywords

Cite

@article{arxiv.2011.14862,
  title  = {Lynx grating spectrometer design: Optimizing chirped transmission gratings},
  author = {Hans Moritz Günther and Ralf K. Heilmann},
  journal= {arXiv preprint arXiv:2011.14862},
  year   = {2023}
}

Comments

will be published in SPIE proceedings

R2 v1 2026-06-23T20:36:09.333Z