Journal article
Measuring the atomic scattering factors near the iridium L-edges for the Athena silicon pore optics reflector
Ehime University1
Okinawa Institute of Science and Technology Graduate University2
NASA Goddard Space Flight Center3
University of Leicester4
JAXA Institute of Space and Astronautical Science5
Osaka University6
National Space Institute, Technical University of Denmark7
Astrophysics and Atmospheric Physics, National Space Institute, Technical University of Denmark8
ESTEC9
Cosine Measurement Systems10
Japan Synchrotron Radiation Research Institute11
Nagoya University12
...and 2 moreAthena, a future high-energy mission, is expected to consist of a large aperture x-ray mirror with a focal length of 12 m. The mirror surface is to be coated with iridium and a low Z overcoat. To define the effective area of the x-ray telescope, the atomic scattering factors of iridium with an energy resolution less than that (2.5 eV) of the x-ray integral field unit are needed.
We measured the reflectance of the silicon pore optics mirror plate coated with iridium in the energy range of 9 to 15 keV and that near the iridium L-edges in steps of 10 and 1.5 eV, respectively, at the synchrotron beamline SPring-8. The L3, L2, and L1 edges were clearly detected around 11,215, 12,824, and 13,428 eV, respectively.
The measured scattering factors were 1/43 % smaller than the corresponding values reported by Henke et al., likely due to the presence of an overlayer on the iridium coating, and were consistent with those measured by Graessle et al. The angular dependence of the reflectivity measured indicates that the iridium surface was extremely smooth, with a surface roughness of 0.3 nm.
Language: | English |
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Year: | 2021 |
ISSN: | 23294124 and 23294221 |
Types: | Journal article |
DOI: | 10.1117/1.JATIS.7.1.014001 |
ORCIDs: | Svendsen, Sara , Christensen, Finn E. , Ferreira, Desiree D.M. and Massahi, Sonny |