@inproceedings{DoehringStollenwerkProserpioetal.2016, author = {D{\"o}hring, Thorsten and Stollenwerk, Manfred and Proserpio, Laura and Breunig, Elias and Friedrich, Peter}, title = {The challenging development of lightweight glass mirrors for future X-ray telescopes}, series = {DGaO Proceedings}, volume = {2016}, booktitle = {DGaO Proceedings}, publisher = {Deutsche Gesellschaft f{\"u}r angewandte Optik}, address = {Erlangen}, organization = {Hochschule Aschaffenburg}, issn = {1614-8436}, url = {http://nbn-resolving.de/nbn:de:0287-2016-B018-0}, pages = {2}, year = {2016}, abstract = {Previously used mirror technologies are not able to fulfill the challenging requirements of future X-ray telescopes. A promising new technology under development is the hot slumping of thin glasses. Challenges, design trades and first results are presented, including the thermal shaping process, the development of low stress coatings and the mirror segments integration concept.}, subject = {R{\"o}ntgenteleskop}, language = {en} } @inproceedings{DoehringProbstEmmerichetal.2017, author = {D{\"o}hring, Thorsten and Probst, Anne-Catherine and Emmerich, Florian and Stollenwerk, Manfred and Stehlikova, Veronika and Friedrich, Peter and Damm, Christine}, title = {Development of iridium coated X-ray mirrors for astronomical applications}, series = {Proceedings of the International Society for Optics and Photonics (SPIE)}, volume = {2017}, booktitle = {Proceedings of the International Society for Optics and Photonics (SPIE)}, number = {10399}, publisher = {SPIE}, doi = {10.1117/12.2273988}, pages = {103991C-1 -- 103991C-8}, year = {2017}, abstract = {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.}, subject = {Iridium}, language = {en} } @inproceedings{DoehringStieglitzHudecetal.2022, author = {D{\"o}hring, Thorsten and Stieglitz, Veronika and Hudec, Rene and Sapsai, Iryna and Friedrich, Peter and Burwitz, Vadim}, title = {Characterization of a lobster-eye type X-ray telescope}, series = {EOSAM-Conference}, volume = {2022}, booktitle = {EOSAM-Conference}, organization = {TH Aschaffenburg}, pages = {1 -- 1}, year = {2022}, abstract = {Lobster-eye type X-ray telescopes use reflecting plano mirrors under grazing incidence and can observe a large field of view. As part of a Bavarian-Czech cooperation, two telescopes were build, equipped with mirrors coated with gold and iridium. Their X-ray characterization was carried out at the PANTER test facility, which simulates parallel starlight incident on the telescopes. The telescopes have an angular resolution of about 4 arc minutes in X-rays and a focal length of about 2 meters. The used X-ray mirrors reflect and focus visible light as well; their functionality in the optical regime was checked in laboratory tests. Now another test campaign will be carried out to examine the telescope resolution for real objects of the visible night sky and the imaging properties for star constellations.}, subject = {R{\"o}ntgenteleskop}, language = {en} } @inproceedings{StehlikovaDoehringSchaeferetal.2019, author = {Stehlikova, Veronika and D{\"o}hring, Thorsten and Sch{\"a}fer, Tobias and Stollenwerk, Manfred and Friedrich, Peter and Burwitz, Vadim and Hartner, Gisela and Bradshaw, Miranda and Liao, Yingyu and Pelliciari, Carlo}, title = {X-ray reflectivity measurements at chromium-iridium tri-layer coatings}, series = {Proceedings of SPIE}, volume = {2019}, booktitle = {Proceedings of SPIE}, number = {11119}, organization = {Max-Planck-Institut f{\"u}r Extraterrestrische Physik}, doi = {http://dx.doi.org/10.1117/12.2530439}, pages = {111191L-1 -- 111191L-6}, year = {2019}, abstract = {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.}, subject = {R{\"o}ntgenastronomie}, language = {en} } @inproceedings{HudecStieglitzDoehringetal.2025, author = {Hudec, Rene and Stieglitz, Veronika and D{\"o}hring, Thorsten and Friedrich, Peter and Burwitz, Vadim}, title = {Novel X-ray optics developed within the AHEAD2020 project}, series = {DGaO-Proceedings}, volume = {2025}, booktitle = {DGaO-Proceedings}, number = {126}, publisher = {DGaO}, organization = {Czech Technical University in Prague}, issn = {1614-8436}, pages = {1 -- 2}, year = {2025}, abstract = {We present a summary of our contribution to the EU Horizon 2020 project AHEAD2020, with emphasis on the X-ray optics work package. The Czech Technical University - together with other collaborating institutes - studied innovative Lobster Eye and Kirkpatrick-Baez X-ray modules, based on the Multi Foil Optics technology. In addition, a student's workshop in December 2023 and a summer school in May 2024 were organized within the project.}, subject = {R{\"o}ntgenoptik}, language = {en} }