Ray-tracing critical-angle transmission gratings for the X-ray Surveyor and Explorer-size missions
Name
990556.pdf
Size
401.36 KB
Format
Adobe PDF
Checksum (MD5)
996202b7dfe31a11060434d8e260db4e
Author(s)
Günther, Hans M.
Heilmann, Ralf K
Marshall, Herman
Bautz, Marshall W.
Huenemoerder, David P.
Nowak, Michael A.
Schulz, Norbert S.
Date Issued
July 2016
Journal
Proceedings of SPIE--the Society of Photo-Optical Instrumentation Engineers
Publisher
SPIE, the International Society of Optical Engineering
Citation
Günther, Hans M., Marshall W. Bautz, Ralf K. Heilmann, David P. Huenemoerder, Herman L. Marshall, Michael A. Nowak, and Norbert S. Schulz. “Ray-Tracing Critical-Angle Transmission Gratings for the X-Ray Surveyor and Explorer-Size Missions.” Edited by Jan-Willem A. den Herder, Tadayuki Takahashi, and Marshall Bautz. Space Telescopes and Instrumentation 2016: Ultraviolet to Gamma Ray (July 18, 2016).
Version
Final published version
Abstract
We study a critical angle transmission (CAT) grating spectrograph that delivers a spectral resolution significantly above any X-ray spectrograph ever own. This new technology will allow us to resolve kinematic components in absorption and emission lines of galactic and extragalactic matter down to unprecedented dispersion levels. We perform ray-trace simulations to characterize the performance of the spectrograph in the context of an X-ray Surveyor or Arcus like layout (two mission concepts currently under study). Our newly developed ray-trace code is a tool suite to simulate the performance of X-ray observatories. The simulator code is written in Python, because the use of a high-level scripting language allows modifications of the simulated instrument design in very few lines of code. This is especially important in the early phase of mission development, when the performances of different configurations are contrasted. To reduce the run-time and allow for simulations of a few million photons in a few minutes on a desktop computer, the simulator code uses tabulated input (from theoretical models or laboratory measurements of samples) for grating efficiencies and mirror reflectivities. We find that the grating facet alignment tolerances to maintain at least 90% of resolving power that the spectrometer has with perfect alignment are (i) translation parallel to the optical axis below 0.5 mm, (ii) rotation around the optical axis or the groove direction below a few arcminutes, and (iii) constancy of the grating period to 1:10 5 . Translations along and rotations around the remaining axes can be significantly larger than this without impacting the performance.
Subjects
ray-tracing, X-ray optics, critical angle transmission grating, X-ray Surveyor, Arcus
MIT Department
MIT Kavli Institute for Astrophysics and Space Research
Terms of Use
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1117/12.2232157
