LEXR: A low-energy X-ray reflectometer for characterization of ATHENA mirror coatings

Henriksen, Peter L.; Christensen, Finn Erland; Massahi, Sonny; Ferreira, Desiree Della Monica; Svendsen, Sara; Jafari, Atefeh; Shortt, Brian

doi:10.1117/12.2528144

Cited by 9 publications

(9 citation statements)

References 7 publications

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“…This indicates that the surface oxidation is low for boron carbide films deposited in the ATHENA coating facility compared to boron carbide films deposited in the DTU Space coating facility inferring a higher compatibility of the boron carbide film deposited in the ATHENA coating facility with the chemical exposure processes 18 . With supporting data from the recently installed Low Energy X-ray Reflectometer we will obtain a deeper understanding of the film composition 19 .…”

Section: Coating Chemical Exposure and Time Stability Studymentioning

confidence: 93%

Installation and commissioning of the silicon pore optics coating facility for the ATHENA mission

Massahi¹,

Christensen²,

Ferreira³

et al. 2019

Optics for EUV, X-Ray, and Gamma-Ray Astronomy IX

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We present the latest progress on the industrial scale coating facility for the Advanced Telescope for High-ENergy Astrophysics (ATHENA) mission. The facility has been successfully commissioned and tested, completing an important milestone in preparation of the Silicon Pore Optics (SPO) production capability. We qualified the coating facility by depositing iridium and boron carbide thin films in different configurations under various process conditions including pre-coating in-system plasma cleaning. The thin films were characterized with X-Ray Reflectometry (XRR) using laboratory X-ray sources Cu K-α at 8.048 keV and PTB's four-crystal monochromator beamline at the synchrotron radiation facility BESSY II in the energy range from 3.6 keV to 10.0 keV. Additional X-ray Photoelectron Spectroscopy (XPS) measurements were performed with Al K-α radiation to analyze the composition of the deposited thin films.

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Section: Coating Chemical Exposure and Time Stability Studymentioning

confidence: 93%

Installation and commissioning of the silicon pore optics coating facility for the ATHENA mission

Massahi¹,

Christensen²,

Ferreira³

et al. 2019

Optics for EUV, X-Ray, and Gamma-Ray Astronomy IX

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“…To characterize the same set of samples at a lower energy, θ-2θ scans were performed with the Low-Energy X-ray Reflectometer (LEXR) at DTU Space 17,18 . The reflectometer has a 1.487 keV Al source, and the detector is a 2D CCD camera.…”

Section: Characterization Tools 221 X-ray Reflectometrymentioning

confidence: 99%

Balancing of residual stress in thin film iridium by utilizing chromium as an underlayer

Massahi

Ferreira

et al. 2020

Space Telescopes and Instrumentation 2020: Ultraviolet to Gamma Ray

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As part of the thin film development for the Athena X-ray telescope and X-ray optics in general, we investigated the residual stress in iridium and chromium thin films deposited using direct current magnetron sputtering. Residual stresses in thin films can affect the performance and adhesion properties of the fabricated thin film coated X-ray optics. We characterized the thin films using X-ray reflectometry to determine the thin film thicknesses and stylus profilometry to determine the residual film stresses. To counterbalance the compressive stress identified in the iridium thin films, we introduced a chromium thin film layer for which the residual stress is tensile beneath the iridium film. However, chromium thin films are known to exhibit a grainy growth resulting in a high surface roughness which was also observed in this work. In this paper, we evaluated the effect on the iridium surface roughness when introducing a chromium underlayer and discussed the effect on the X-ray optics performance.

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“…Therefore, the surface and bilayer interface roughnesses were coupled. In order to measure potential evolution of the surface roughness, measurements at a low-energy XRR facility such the recently installed LEXR (Low-Energy X-ray Reflectometer) at DTU Space are necessary 19 . The Ir/SiC periodic multilayer sample was measured with 8.047 keV XRR and the data was modelled as 9 periodic bilayers with an independent Ir/SiC cap layer.…”

Section: Long Term Stability Of Ir/sic Coatingsmentioning

confidence: 99%

Performance and time stability of Ir/SiC X-ray mirror coatings for ATHENA

Svendsen¹,

Massahi²,

Ferreira³

et al. 2019

Optics for EUV, X-Ray, and Gamma-Ray Astronomy IX

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Excellent X-ray reflective mirror coatings are key in order to meet the performance requirements of the ATHENA telescope. The baseline coating design of ATHENA was initially formed by Ir/B 4 C but extensive studies have identified critical issues with the stability of the B 4 C top layer which shows strong evolution over time and appears incompatible with the industrialization processes required for the production of mirror modules. Motivated by the need for a compatible top layer material to improve the telescope performance at low energies and based on simulated performance, a SiC top layer has been selected as the best substitute to B 4 C. We report the latest development of Ir/SiC bilayer coatings optimized for ATHENA and the characterization of coating performance and stability.

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LEXR: A low-energy X-ray reflectometer for characterization of ATHENA mirror coatings

Cited by 9 publications

References 7 publications

Installation and commissioning of the silicon pore optics coating facility for the ATHENA mission

Installation and commissioning of the silicon pore optics coating facility for the ATHENA mission

Balancing of residual stress in thin film iridium by utilizing chromium as an underlayer

Performance and time stability of Ir/SiC X-ray mirror coatings for ATHENA

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