1. Large-format X-Ray Reflection Grating Operated in an Echelle-like Mounting.
- Author
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DeRoo, Casey T., McEntaffer, Randall L., Donovan, Benjamin D., Grisé, Fabien, Eichfeld, Chad, Burwitz, Vadim, Hartner, Gisela, Pelliciari, Carlo, and Caria, Marlis-Madeleine La
- Subjects
MONTE Carlo method ,BARYONS ,MARKOV chain Monte Carlo ,SOFT X rays ,FIREPLACES ,X-ray reflection - Abstract
We report on resolving power measurements of an X-ray reflection grating designed for use in an astronomical soft X-ray spectrograph. The grating was patterned via electron-beam lithography (EBL) to have fanned grooves to match the convergence of an illuminating beam. Grating measurements were conducted in an echelle-like mounting, which yields access to high diffraction orders in the soft X-ray bandpass (0.2–2.0 keV). By comparing the zeroth-order line-spread function to the telescope focus, we find evidence for minimal broadening (<1″) introduced by the figure of the grating. In addition, we fit for the spectral resolution (R = λ/Δλ) intrinsic to this grating using a Bayesian Markov Chain Monte Carlo approach. Using an ensemble fitting technique, we find that the grating resolution R exceeds 2200 (3σ lower bound). This current grating resolution meets the performance required for a notional soft X-ray grating spectroscopy mission measuring hot baryonic material in the extended halos of galaxies. Using ray-trace simulations, we identify a geometric aberration resulting from path length differences across the width of the grating as a limiting factor in assessing the resolution of these gratings and discuss methods for placing better constraints on the inherent resolution of X-ray astronomical reflection gratings fabricated using EBL. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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