TY - CHAP A1 - Stehlikova, Veronika A1 - Probst, Anne-Catherine A1 - Nentvich, Ondrej A1 - Urban, Martin A1 - Inneman, Adolf A1 - Sieger, Ladislav A1 - Marsikova, Veronika A1 - Döhring, Thorsten T1 - Development of iridium coated silicon X-ray mirrors for Lobster Eye astronomical telescopes T2 - Proceedings of EOSMOS 2017 N2 - In the field of X-ray astronomy different types of telescope optics based on grazing incidence mirrors can be used. This contribution presents a special design of a Lobster Eye wide-field telescope with mirrors based on flat silicon wafers and the task of coating such mirror substrates with reflective iridium layers. KW - X-ray KW - mirror KW - telescope KW - Lobster Eye KW - iridium KW - Iridium KW - Röntgenteleskop Y1 - 2017 VL - 2017 IS - EOSMOS 2017 SP - 1 EP - 2 PB - European Optical Society ER - TY - CHAP A1 - Stehlikova, Veronika A1 - Döhring, Thorsten A1 - Stollenwerk, Manfred A1 - Stadtmüller, Johannes A1 - Marsikova, Veronika A1 - Hudec, Rene A1 - Flachs, Dennis A1 - Burwitz, Vadim A1 - Hartner, Gisela A1 - Rukdee, Surangkhana A1 - Müller, Thomas A1 - Schmidt, Thomas A1 - Inneman, Adolf A1 - Klementova, Mariana A1 - Zeising, Sebastian A1 - Langmeier, Andreas T1 - Lobster eye type X-ray telescope with chromium-iridium coated tri-layer mirrors T2 - Proceedings of SPIE N2 - For space-born astronomical X-ray telescopes, iridium-based reflective layer systems are known as highly effective mirrors coatings. During the recent years, Aschaffenburg University of Applied Sciences and the Czech Technical University in Prague jointly developed stress compensated chromium-iridium coatings for this application. To overcome the disturbing reflectivity reduction of the iridium absorption edge around 2 keV photon energy, thin overcoat layers of chromium were applied in addition. Now a prototype of a wide-field, imaging X-ray telescope of Lobster Eye type is assembled at the company RIGAKU. For this purpose a small series of 34 mirrors based on 100 x 50 mm semiconductor grade silicon substrates has been coated at Aschaffenburg University. The applied tri-layer system consists of a stack of 40 nm chromium, which act as adhesive layer and compensates layer stress, a 30 nm iridium thick reflective layer, and an additional overcoat layer of 6 nm chromium. This layer system have been analysed by AFM and TEM images. The mirrors are assembled into an aluminium frame to build a 2D Lobster Eye type telescope. The designed focal length of this wide field X-ray telescope is two meter. To study the performance of the tri-layer coating system, a twin LE telescope with convenient gold coatings was manufactured also. Performance measurements of both telescopes and under same conditions are planned at the PANTER test facility at the Max-Planck Institute for Extraterrestrial Physics. First experimental results, their comparison with theoretical simulations and the comparison between both models will be presented in this contribution. KW - telescope KW - Lobster Eye KW - X-ray KW - mirror KW - iridium KW - Röntgenteleskop KW - Röntgenspiegel Y1 - 2021 U6 - https://doi.org/https://doi.org/10.1117/12.2589266 VL - 2021 IS - 11776 SP - 1177605-1 EP - 1177605-8 PB - SPIE ER - TY - JOUR A1 - Stehlikova, Veronika A1 - Probst, Anne-Catherine A1 - Nentvich, Ondrej A1 - Urban, Martin A1 - Sieger, Ladislav A1 - Döhring, Thorsten A1 - Hudec, René ED - Skopal, Augustín T1 - Study of multiple layers coatings for X–ray mirrors JF - Contributions of the Astronomical Observatory Skalnaté Pleso N2 - This paper focuses on a theoretical background that motivated the experimental campaign of multiple layer coatings of X-ray mirrors, and the first results of the testing of the prepared samples. Simulations of the use of different overcoats were performed in order to improve the reflectivity of thin iridium coatings designed for X-ray optics effective in the energy up to 10 keV. Samples based on these simulations were prepared and are being tested for the properties that influence the X-ray optical performance, such as layer homogeneity, density and surface micro-roughness. Further the topic of the coating stress was addressed, as it is an issue in case of thin, lightweight X-ray mirrors and affects the time stability of layers. The discussion and preliminary results conclude our contribution. KW - X-ray KW - optics KW - coating KW - reflectivity KW - iridium KW - Röntgenspiegel KW - Iridium Y1 - 3018 UR - https://www.ta3.sk/caosp/Eedition/Abstracts/2018/Vol_48/No_3/pp488-497_abstract.html VL - 2018 IS - 48 SP - 488 EP - 497 ER - TY - CHAP A1 - Döhring, Thorsten A1 - Probst, Anne-Catherine A1 - Stollenwerk, Manfred A1 - Emmerich, Florian A1 - Stehlíková, Veronika A1 - Inneman, Adolf ED - Hudec, René ED - Pina, Ladislav T1 - Prototyping iridium coated mirrors for X-ray astronomy T2 - Proceedings of the International Society for Optics and Photonics N2 - X-ray astronomy uses space-based telescopes to overcome the disturbing absorption of the Earth´s atmosphere. The telescope mirrors are operating at grazing incidence angles and are coated with thin metal films of high-Z materials to get sufficient reflectivity for the high-energy radiation to be observed. In addition the optical payload needs to be light-weighted for launcher mass constrains. Within the project JEUMICO, an acronym for “Joint European Mirror Competence”, the Aschaffenburg University of Applied Sciences and the Czech Technical University in Prague started a collaboration to develop mirrors for X-ray telescopes. The X-ray telescopes currently developed within this Bavarian- Czech project are of Lobster eye type optical design. Corresponding mirror segments use substrates of flat silicon wafers which are coated with thin iridium films, as this material is promising high reflectivity in the X-ray range of interest. The deposition of the iridium films is based on a magnetron sputtering process. Sputtering with different parameters, especially by variation of the argon gas pressure, leads to iridium films with different properties. In addition to investigations of the uncoated mirror substrates the achieved surface roughness has been studied. Occasional delamination of the iridium films due to high stress levels is prevented by chromium sublayers. Thereby the sputtering parameters are optimized in the context of the expected reflectivity of the coated X-ray mirrors. In near future measurements of the assembled mirror modules optical performances are planned at an X-ray test facility. KW - X-ray KW - iridium KW - mirror KW - lightweight optic KW - Lobster Eye KW - Iridium KW - Röntgenastronomie KW - Spiegelteleskop Y1 - 2017 U6 - https://doi.org/10.1117/12.2265931 VL - 2017 IS - 10235 SP - 1023504-1 EP - 1023504-8 PB - SPIE International Society for Optics and Photonics CY - Bellingham WA ER - TY - CHAP A1 - Döhring, Thorsten A1 - Probst, Anne-Catherine A1 - Emmerich, Florian A1 - Stollenwerk, Manfred A1 - Stehlikova, Veronika A1 - Friedrich, Peter A1 - Damm, Christine T1 - Development of iridium coated X-ray mirrors for astronomical applications T2 - Proceedings of the International Society for Optics and Photonics (SPIE) N2 - Future space-based X-ray observatories need to be very lightweight for launcher mass constraints. Therefore they will use a reduced mirror thickness, which results in the additional requirement of low coating stress to avoid deformation of the initial precisely shaped mirror substrates. Due to their excellent reflection properties iridium coatings are sometimes applied for grazing incidence mirrors in astronomical X-ray telescopes. At Aschaffenburg University of Applied Sciences the coating of thin iridium films by an RF-magnetron sputtering technique is under development. The work is embedded in collaborations with the Max-Planck-Institute for Extraterrestrial Physics in Germany, the Czech Technical University in Prague, the Osservatorio Astronomico di Brera in Italy, the German Leibniz Institute for Solid State and Materials Research in Dresden, and the French Institute Fresnel. Sputtering with different parameters leads to iridium films with different properties. The current work is focused on the microstructure of the iridium coatings to study the influence of the substrate and of the argon gas pressure on the thin film growing process. Correlations between coating density, surface micro-roughness, the crystalline structure of the iridium layers, and the expected reflectivity of the X-ray mirror as well as coating stress effects are presented and discussed. The final goal of the project is to integrate the produced prototype mirrors into an X-ray telescope module. On a longer timescale measurements of the mirror modules optical performance are planned at the X-ray test facility PANTER. KW - X-ray KW - telescope KW - mirror KW - iridium KW - coating KW - Iridium KW - Röntgenteleskop Y1 - 2017 U6 - https://doi.org/10.1117/12.2273988 VL - 2017 IS - 10399 SP - 103991C-1 EP - 103991C-8 PB - SPIE ER - TY - CHAP A1 - Stehlikova, Veronika A1 - Proserpio, Laura A1 - Friedrich, Peter A1 - Madarasz, Emanuel A1 - Breunig, Elias A1 - Burwitz, Vadim A1 - Döhring, Thorsten A1 - Probst, Anne-Catherine T1 - Indirect glass slumping of grazing incidence mirror segments for lightweight x-ray telescopes T2 - Proceedings of the International Society for Optics and Photonics (SPIE) N2 - The paper provides a description of recent progress in the development of lightweight, precision and highthroughput grazing-incidence mirrors for X-ray astronomy made of glass. In particular, the indirect slumping technology under investigation at the Max Planck Institute for Extraterrestrial Physics (MPE) is reviewed and recent activities are presented together with the research approach. The glass slumping technique foresees several steps: a thermal forming process using a suitable mould; a re ective layer application; the alignment and integration of mirror segments into a supporting structure; and the � nal veri� cation of prototype modules using X-rays. Each step is considered at MPE, with the involvement of partner institutes and universities. The last year of activities was mainly dedicated to the procurement of new moulds and to the application of Iridium coating. The main results will be presented. KW - X-ray KW - iridium KW - telescope KW - slumping KW - glass KW - Iridium KW - Röntgenteleskop Y1 - 2017 U6 - https://doi.org/10.1117/12.2272671 VL - 2017 IS - 10399 SP - 103991Z-1 EP - 103991Z-7 PB - SPIE ER - TY - JOUR A1 - Probst, Anne-Catherine A1 - Stollenwerk, Manfred A1 - Emmerich, Florian A1 - Büttner, Andre A1 - Zeising, Sebastian A1 - Stadtmüller, Johannes A1 - Riethmüller, Franziska A1 - Stehlikova, Veronika A1 - Mingwu, Wen A1 - Proserpio, Laura A1 - Damm, Christine A1 - Rellinghaus, Bernd A1 - Döhring, Thorsten T1 - Influence of sputtering pressure on the nanostructure and the X-ray reflectivity of iridium coatings JF - Surface and Coatings Technology N2 - Reflective mirror coatings made of iridium are used in X-ray telescopes of the Chandra X-ray Observatory (CXO) launched in 1999 by the National Aeronautics and Space Administration (NASA) to investigate astronomical sources at photon energies below 10. keV. These coatings were produced in a DC magnetron sputtering process and have so far proven their suitability for space-based applications. We are considering in the present paper the processing of thin iridium films for lightweight telescopes using the radio frequency magnetron sputtering technique with an oblique angle deposition. The coating development presented here is focused on the influence of total sputtering pressure on film properties as well as on its impact on the mirror's performance. Characterisation methods such as X-ray diffractometry, X-ray reflectometry, atomic force microscopy and transmission electron microscopy have been used. Correlations between morphology, density, surface micro-roughness, crystal structure of the iridium layer and the expected reflectivity of the X-ray mirror are described and discussed. KW - Iridium KW - sputtering KW - microstructure KW - coating KW - X-ray KW - Iridium KW - Röntgenteleskop Y1 - 2017 UR - https://doi.org/10.1016/j.surfcoat.2017.10.062 SN - 0257-8972 VL - 2017 IS - 343 SP - 101 EP - 107 ER - TY - CHAP A1 - Stehlikova, Veronika A1 - Döhring, Thorsten A1 - Schäfer, Tobias A1 - Stollenwerk, Manfred A1 - Friedrich, Peter A1 - Burwitz, Vadim A1 - Hartner, Gisela A1 - Bradshaw, Miranda A1 - Liao, Yingyu A1 - Pelliciari, Carlo T1 - X-ray reflectivity measurements at chromium-iridium tri-layer coatings T2 - Proceedings of SPIE N2 - Studying astronomical objects in the X-ray regime, iridium-based layer systems are highly effective reflective materials for telescopes mirrors. Aschaffenburg University and the Czech Technical University in Prague jointly developed stress compensated chromium-iridium coatings. To overcome the disturbing reflectivity reduction of the iridium absorption edge around 2 keV photon energy and improve general reflectivity at lower incident energies, thin overcoat layers of chromium have been applied in addition. Corresponding measurements at several X-ray lines have been performed on these samples at the PANTER test facility of the Max-Planck Institute for extraterrestrial Physics. A part of the experimental results and their comparison with theoretical simulations are presented in this contribution. KW - iridium KW - mirror KW - coating KW - reflectivity KW - X-ray KW - Röntgenastronomie KW - Röntgenteleskop Y1 - 2019 U6 - https://doi.org/http://dx.doi.org/10.1117/12.2530439 VL - 2019 IS - 11119 SP - 111191L-1 EP - 111191L-6 ER - TY - CHAP A1 - Döhring, Thorsten A1 - Stollenwerk, Manfred A1 - Stadtmüller, Johannes A1 - Zeising, Sebastian A1 - Flachs, Dennis A1 - Stehlikova, Veronika A1 - Burwitz, Vadim A1 - Krumrey, Michael K. A1 - Cotroneo, Vincenzo A1 - Klementova, Mariana T1 - Characterisation of X-ray mirrors based on chromium-iridium tri-layer coatings T2 - Proceedings of SPIE N2 - Iridium-based layer systems are highly effective mirror coatings for space-born X-ray telescopes. During the recent years, Aschaffenburg University of Applied Sciences and its partners developed stress compensated chromium-iridium coatings for such astronomical applications, using chromium as an adhesive layer between iridium reflective layer and mirror substrate. However, there was room for improvement: To overcome the disturbing reflectivity reduction of the iridium absorption edge around 2 keV photon energy, thin overcoat layers of chromium are applied in addition now. This layer system has been analyzed by atomic force microscopy and transmission electron microscopy images. Furthermore, the reflectivity of such innovative X-ray mirrors based on chromium-iridium tri-layer coatings was recently measured at PTB's four-crystal monochromator beamline at the synchrotron radiation facility BESSY II. The experimental results, obtained for photon energies between 1.9 keV and 11 keV at two grazing incidence angles (0.6 degree and 0.9 degree) and their comparison with corresponding simulations are presented in this contribution. When compared to simulations of pure iridium coatings, a significantly higher reflectivity was achieved especially in the soft X-ray regime between 2 keV and 4 keV. Such chromium-iridium tri-layer coatings have high potential to increase the effective area for X-ray telescopes in Lobster Eye Design, for Wolter-I type X-ray optics, and for silicon pore optics as considered for the ATHENA telescope of the European Space Agency. KW - iridium KW - mirror KW - X-ray KW - coating KW - telescope KW - Röntgenspiegel KW - Röntgenteleskop KW - Iridium Y1 - 2021 U6 - https://doi.org/https://doi.org/10.1117/12.2592551 VL - 2021 IS - 11776 SP - 1177607-1 EP - 11776076 PB - SPIE ER -