@inproceedings{DoehringHudec2025, author = {D{\"o}hring, Thorsten and Hudec, Rene}, title = {One decade of joint Bavarian-Czech projects on astronomical X-ray optics}, volume = {2025}, number = {16}, publisher = {16th International Conference on Astronomical X-ray Optics}, address = {Prag}, organization = {TH Aschaffenburg}, pages = {1 -- 1}, year = {2025}, abstract = {Since ten years, Aschaffenburg University of Applied Sciences and the Czech technical university in Prague are now cooperating. During the recent decade, eleven joint projects have been executed, mainly targeting the development of astronomical X-ray optics. The bilateral cooperation also included the exchange of PhD students and scientists, cost compensation for conference participations, and the sponsoring of scientific conferences (AXRO and IBWS). The scientific output up to date are more than twenty joint publications and many individual conference contributions of the project partners in addition. The Bavarian-Czech Academic Agency (BTHA) has funded all of these projects. It is the goal of the Bavarian-Czech Academic Agency to support the academic collaboration in research and education and to contribute to an increased cooperation of the two neighbored countries Bavaria and Czech Republic in general. We will give a review on one decade of our Bavarian-Czech cooperation and on the scientific results of our joint projects on astronomical X-ray optics.}, subject = {R{\"o}ntgenoptik}, language = {en} } @inproceedings{StehlikovaDoehringStollenwerketal.2021, author = {Stehlikova, Veronika and D{\"o}hring, Thorsten and Stollenwerk, Manfred and Stadtm{\"u}ller, Johannes and Marsikova, Veronika and Hudec, Rene and Flachs, Dennis and Burwitz, Vadim and Hartner, Gisela and Rukdee, Surangkhana and M{\"u}ller, Thomas and Schmidt, Thomas and Inneman, Adolf and Klementova, Mariana and Zeising, Sebastian and Langmeier, Andreas}, title = {Lobster eye type X-ray telescope with chromium-iridium coated tri-layer mirrors}, series = {Proceedings of SPIE}, volume = {2021}, booktitle = {Proceedings of SPIE}, number = {11776}, publisher = {SPIE}, organization = {Czech Technical University in Prague}, doi = {https://doi.org/10.1117/12.2589266}, pages = {1177605-1 -- 1177605-8}, year = {2021}, abstract = {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.}, subject = {R{\"o}ntgenteleskop}, language = {en} } @inproceedings{DoehringStollenwerkStadtmuelleretal.2021, author = {D{\"o}hring, Thorsten and Stollenwerk, Manfred and Stadtm{\"u}ller, Johannes and Zeising, Sebastian and Flachs, Dennis and Stehlikova, Veronika and Burwitz, Vadim and Krumrey, Michael K. and Cotroneo, Vincenzo and Klementova, Mariana}, title = {Characterisation of X-ray mirrors based on chromium-iridium tri-layer coatings}, series = {Proceedings of SPIE}, volume = {2021}, booktitle = {Proceedings of SPIE}, number = {11776}, publisher = {SPIE}, organization = {TH Aschaffenburg}, doi = {https://doi.org/10.1117/12.2592551}, pages = {1177607-1 -- 11776076}, year = {2021}, abstract = {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.}, subject = {R{\"o}ntgenspiegel}, language = {en} } @inproceedings{KhropostRiethmuellerDoehringetal.2025, author = {Khropost, Diana and Riethm{\"u}ller, Franziska and D{\"o}hring, Thorsten and Flachs, Dennis and H{\"u}lag{\"u}, Deniz and Hertwig, Andreas and Cotroneo, Vincenzo and Gibertini, Eugenio}, title = {Polydopamine: a bio-inspired polymer for X-ray mirror coatings and other technical applications}, series = {EUV and X-ray Optics: Synergy between Laboratory and Space IX}, volume = {2025}, booktitle = {EUV and X-ray Optics: Synergy between Laboratory and Space IX}, number = {13531}, editor = {Hudec, Ren{\´e} and Pina, Ladislav}, publisher = {SPIE}, doi = {10.1117/12.3056298}, pages = {135310H-1 -- 135310H-11}, year = {2025}, abstract = {Although the organic molecule dopamine (3,4-dihydroxyphenethylamine) is commonly known as one of the "hormones of happiness", thin polymer films of polydopamine (PDA) also have interesting technical properties. PDA is a very strong glue that sticks on almost everything, even under water. In nature, PDA is found in the byssal thread cuticles of mussels. When produced by dip-coating, the self-organizing PDA layers grow in a reproducible thickness of single or multiple molecule monolayers of a few nanometres thickness only. Here we present an optimized preparation regime as derived from polymerization analysis through absorption spectroscopy. One application is the use of thin PDA overcoatings to increase the soft X-ray reflectivity of astronomical X-ray mirrors. Furthermore, we give an outlook to other technical applications for this interesting material, presenting this bio-inspired organic polymer as an innovative technical solution for the future, with applications such as PDA-based super-capacitors and its promising role in enhancing separator materials for batteries.}, subject = {R{\"o}ntgenspiegel}, language = {en} } @misc{KhropostDoehringRiethmuelleretal.2024, author = {Khropost, Diana and D{\"o}hring, Thorsten and Riethm{\"u}ller, Franziska and H{\"u}lag{\"u}, Deniz}, title = {Poly-dopamine - an organic material for X-ray mirror coatings and other technical applications}, series = {AXRO 2024 - 15th International Conference on Astronomical X-Ray Optics}, volume = {2024}, journal = {AXRO 2024 - 15th International Conference on Astronomical X-Ray Optics}, organization = {TH Aschaffenburg}, pages = {1 -- 1}, year = {2024}, abstract = {Although the organic molecule dopamine (3,4-dihydroxyphenethylamine) is commonly known as the "hormone of happiness", thin polymer films of poly-dopamine also have interesting technical properties. When produced by dip coating, these self-organizing layers grow in a reproducible thickness of single or multiple molecule monolayers of a few nanometre thickness only. One application is the use of thin poly-dopamine overcoatings to increase the soft X-ray reflectivity of astronomical X-ray mirrors. We thereby introduce a method of determining the layer thickness of poly-dopamine, which is based on spectroscopic ellipsometry measurements and applies an optical model for the poly-dopamine layers including their dielectric function. Furthermore, we give an outlook to other technical applications for this promising material, presenting this bio-inspired organic polymer as an innovative technical solution for the future.}, subject = {R{\"o}ntgenspiegel}, language = {en} }