Simulation and modeling of silicon pore optics for the ATHENA x-ray telescope
Date Issued
2016
Author(s)
•
Christensen, Finn Erland
•
Bavdaz, Marcos
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•
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Della Monica Ferreira, D.
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Knudsen, Erik
•
Massahi, Sonny
•
•
•
Shortt, Brian
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Tayabaly, Kashmira
•
Westergaard, Niels
•
Wille, Erik
Abstract
The ATHENA X-ray observatory is a large-class ESA approved mission, with launch scheduled in 2028. The technology of silicon pore optics (SPO) was selected as baseline to assemble ATHENA's optic with more than 1000 mirror modules, obtained by stacking wedged and ribbed silicon wafer plates onto silicon mandrels to form the Wolter-I configuration. Even if the current baseline design fulfills the required effective area of 2 m2 at 1 keV on-axis, alternative design solutions, e.g., privileging the field of view or the off-axis angular resolution, are also possible. Moreover, the stringent requirement of a 5 arcsec HEW angular resolution at 1 keV entails very small profile errors and excellent surface smoothness, as well as a precise alignment of the 1000 mirror modules to avoid imaging degradation and effective area loss. Finally, the stray light issue has to be kept under control. In this paper we show the preliminary results of simulations of optical systems based on SPO for the ATHENA X-ray telescope, from pore to telescope level, carried out at INAF/OAB and DTU Space under ESA contract. We show ray-tracing results, including assessment of the misalignments of mirror modules and the impact of stray light. We also deal with a detailed description of diffractive effects expected in an SPO module from UV light, where the aperture diffraction prevails, to X-rays where the surface diffraction plays a major role. Finally, we analyze the results of X-ray tests performed at the BESSY synchrotron, we compare them with surface finishing measurements, and we estimate the expected HEW degradation caused by the X-ray scattering.
Coverage
Space Telescopes and Instrumentation 2016: Ultraviolet to Gamma Ray
All editors
den Herder, Jan-Willem A.; Takahashi, Tadayuki; Bautz, Marshall
Series
Volume
9905
Start page
99055O
Conferenece
Space Telescopes and Instrumentation 2016: Ultraviolet to Gamma Ray
Conferenece place
Edinburgh, UK
Conferenece date
26 June-1 July, 2016
Issn Identifier
0277-786X
Ads BibCode
2016SPIE.9905E..5OS
Rights
open.access
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