TY - CHAP A1 - Hudec, Rene A1 - Gille, Florian A1 - Guimbelot, Elzear A1 - Tichy, Vladimir A1 - Döhring, Thorsten T1 - Effective areas of astronomical X-ray optics for cubesats and rocket experiments T2 - DGaO Proceedings N2 - The effective area is one of the main telescope parameters when justifying real space application. We discuss the estimation of the effective collecting area of an X-ray telescope by two different methods, an analytical method and a simulation algorithm, and then compare the results. The Lobster Eye type telescopes considered here are designed for rocket experiments and CubeSat flights. KW - X-ray KW - telescope KW - satellite KW - effective area KW - Lobster Eye KW - Röntgenteleskop Y1 - 2022 UR - https://www.dgao-proceedings.de/download/123/123_p12.pdf SN - 1614-8436 VL - 2022 IS - 123 SP - 1 EP - 2 PB - DGaO ER - TY - CHAP A1 - Döhring, Thorsten A1 - Stieglitz, Veronika A1 - Hudec, Rene A1 - Sapsai, Iryna A1 - Friedrich, Peter A1 - Burwitz, Vadim T1 - Characterization of a lobster-eye type X-ray telescope T2 - EOSAM-Conference N2 - 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. KW - Lobster-Eye KW - X-ray KW - telescope KW - iridium KW - mirror KW - Röntgenteleskop KW - Iridium KW - Röntgenspiegel Y1 - 2022 UR - https://www.europeanoptics.org/events/eos/eosam2022.html VL - 2022 SP - 1 EP - 1 ER - TY - GEN A1 - Döhring, Thorsten A1 - Rödling, Claudius A1 - Kimmel, Kevin A1 - Zeising, Sebastian A1 - Stadtmüller, Johannes A1 - Stollenwerk, Manfred A1 - Verma, Shruti A1 - Rees, Paul T1 - Optical characterization of reflective coatings for astronomical telescope mirrors T2 - DGaO Jahrestagung N2 - With ground based optical telescopes astronomers observe celestial objects over a wide spectral range. As usually three or even more reflections at telescope mirrors are involved, good reflection properties of the mirror coatings are important. The aluminum evaporation technique has been - and is still - the standard solution for the reflective coatings of large astronomical mirrors. Such coatings have excellent reflectivity in the ultraviolet and in the visible, but perform poorly in the infrared. Silver is the metal having highest reflectivity for wavelengths longward of 400 nm, but isn´t the best choice for reflectivity in the ultraviolet and for blue light. To avoid degradation by oxidation, durable silver coatings need to be protected by transmitting overcoating layers. In the presented study, different metallic coatings – including unusual ones like sputtered iridium - are characterized to identify a coating that is most suitable for the spectral range from ultraviolet to infrared. Experimental results are compared to simulations based on the complex refractive indices of these materials. Thereby dependence of incidence angle and polarization is also considered. N2 - Poster KW - mirror KW - coating KW - iridium KW - astronomy KW - telescope KW - Spiegelteleskop Y1 - 2021 UR - https://dgao.de/jahrestagung/ VL - 2021 SP - 1 EP - 1 ER - TY - CHAP A1 - Döhring, Thorsten A1 - Rödling, Claudius A1 - Kimmel, Kevin A1 - Zeising, Sebastian A1 - Stadtmüller, Johannes A1 - Stollenwerk, Manfred A1 - Verma, Shruti A1 - Rees, Paul T1 - Optical characterization of reflective coatings for astronomical telescope mirrors T2 - DGaO Proceedings N2 - Aluminium evaporation is still the standard solution for reflective coatings of large astronomical mirrors. Silver and gold are also used in specific cases depending on the targeted wavelength. This study characterized different metallic coatings - including unusual ones like sputtered iridium - to identify the most suitable mirror coating for the spectral range from ultraviolet to infrared wavelengths. KW - Iridium KW - mirror KW - coating KW - reflectivity KW - telescope KW - Spiegelteleskop Y1 - 2021 UR - https://www.dgao-proceedings.de/download/122/122_p4.pdf SN - 1614-8436 VL - 2021 IS - 122 SP - 1 EP - 1 PB - DGaO ER - TY - JOUR A1 - Döhring, Thorsten A1 - Pribulla, Theodor A1 - Komzik, Richard A1 - Mann, Michael A1 - Sivanic, Peter A1 - Stollenwerk, Manfred T1 - Slovak-Bavarian collaboration on the development of telescope instrumentation JF - Contributions of the Astronomical Observatory Skalnate Pleso N2 - Within the project SLOBATCO (Slovak-Bavarian Telescope Collaboration) the Astronomical Institute of the Slovak Academy of Sciences and Aschaffenburg University of Applied Sciences collaborate in the development and commissioning of scientific instrumentation for the new Ø1.3 m astronomical telescope at the Skalnaté Pleso observatory. The joint project is funded by the Bavarian Academic Center for Central, Eastern and Southeastern Europe (BAYHOST). Planned technical work packages are targeting the filter wheel software for the VIS camera, additional IR filters, and an upgrade of the mirror coating facility by additional sputtering equipment. KW - telescope KW - instrumentation KW - filter KW - camera KW - coating KW - Spiegelteleskop Y1 - 2019 UR - https://www.ta3.sk/caosp/Eedition/FullTexts/vol49no2/pp154-158.pdf VL - 2019 IS - 49 / 2 SP - 154 EP - 158 ER - TY - GEN A1 - Mann, Michael A1 - Döhring, Thorsten A1 - Pribulla, Theodor A1 - Komzik, Richard A1 - Sivanic, Peter A1 - Stollenwerk, Manfred ED - Skopal, Augustin T1 - Power quality evaluation for observatories N2 - Within the project SLOBATCO the question did arise, to what extend observatories have to rely on adequate power quality, e.g. the perfect sinusoidal shape of supply voltage and current, in order to ensure safe operation and accurate measurement results. International power quality standards are put in perspective with requirement specifications. Telescope operators indicate partial or total loss of function of measurement instruments. Measurements conducted during SLOBATCO project substantiate the need for power quality measurement campaigns. N2 - Poster KW - instrumentation KW - site testing KW - telescope KW - Sternwarte KW - Elektrizitätsversorgung Y1 - 2019 ER - TY - CHAP A1 - Pareschi, Giovanni A1 - Civitani, Marta Maria A1 - Sironi, Giorgia A1 - Yang, Yang A1 - Cotroneo, Vincenzo A1 - Valsecchi, Giuseppe A1 - Magagnin, Luca A1 - Döhring, Thorsten A1 - Bradshaw, Miranda A1 - Burwitz, Vadim A1 - Pelliciari, Carlo T1 - Reflectivity-enhancement at low x-ray energies in astronomical telescopes using low-density overcoatings: alternative materials and deposition methods T2 - Proceedings of SPIE N2 - Low density overcoatings (mainly based on materials containing Carbon) onto usual high-density coatings (based i.e. on materials like e.g. like Ir, Au or Pt) have been proposed since many years ago in order to enhance the X- ray reflectivity at low energy (between 0.5 and 4 keV) of X-ray astronomical optics. The trick is to make use of the total reflection from the thin low-density material (which does not suffer much the photoelectric absorption) at low X-ray energies; the reflection of photons at higher energies (< 4 keV) occurs thanks to the much denser material under the overcoating. For several future projects, like e.g. ATHENA, LYNX and eXTP, it is foreseen the use of low-density overcoatings that will importantly increase the effective area at low X-ray energies. In this paper we will introduce the use of overcoatings based on materials different from the usual ones considered so far like C, B4C and SiC. In particular, we will discuss about a novel approach based on the use of thin layer of a Carbon-like materials deposited using a dip coating method. A possible combination with an intermediate thin layer of Chromium deposited e.g. via sputtering onto the usual high density material (Ir, Au or Pt) before the application of the Carbon-like material is also considered in the study, because it can further greatly enhance the soft X-ray effective area of future X-ray telescopes. KW - coating KW - X-ray KW - telescope KW - iridium KW - Röntgenteleskop Y1 - 2019 U6 - https://doi.org/https://doi.org/10.1117/12.2532392 VL - 2019 IS - 11119 SP - 11119OS-1 EP - 11119OS-13 PB - SPIE ER - TY - GEN A1 - Döhring, Thorsten T1 - Advanced Materials and Manufacturing Technologies for Space Applications T2 - Proceedings of International Research Days N2 - The goal of this project is to develop satellite components for space-based astronomical satellite payloads. Thereby advanced materials like iridium and innovative manufacturing technologies will be applied. After environmental testing and space qualifications tests it is planned to do an astronomical experiment with a stratospheric balloon or a sounding rocket. The work is embedded in ACCASI („Aschaffenburg Competence Center for Astronomical and Space Instumentation“) N2 - Poster KW - satellite KW - iridium KW - telescope KW - mirror KW - Satellitentechnik KW - Iridium KW - Spiegelteleskop Y1 - 2021 VL - 2021 ER - TY - CHAP A1 - Hudec, Rene A1 - Stieglitz, Veronika A1 - Döhring, Thorsten A1 - Friedrich, Peter A1 - Burwitz, Vadim T1 - Novel X-ray optics developed within the AHEAD2020 project N2 - 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 (LE) and Kirkpatrick-Baez (KB) X-ray modules, based on the Multi Foil Optics technology (MFO). In addition, two major events were organized, namely a students workshop in December 2023 and a summer school in May 2024. The KB optics represents a promising and cost effective alternative to the currently used Wolter I telescopes. The LE X-ray optics, based on the Schmidt design, has a wide field of view (FOV) with a short focal length, making it suitable for CubeSat application. Thereby the 2D LE optics consist of two orthogonal sub-modules of flat smooth reflecting foils, each sub-modules focuses in one direction. The advantage of such optics is that it preserves the angular resolution throughout the FOV even for off-axis points, as demonstrated by simulations and measurements. There was a collaboration with Aschaffenburg University in design, development, and testing of the double LE module HORUS, comparing different reflecting coatings. KW - Horizon2020 KW - astronomy KW - telescope KW - X-ray KW - Röntgenoptik KW - Beschichtung Y1 - 2025 UR - https://www.dgao-proceedings.de/abstract/abstract_only.php?id=3236 SP - 1 EP - 1 PB - DGaO ER - TY - CHAP A1 - Hudec, Rene A1 - Stieglitz, Veronika A1 - Döhring, Thorsten A1 - Friedrich, Peter A1 - Burwitz, Vadim T1 - Novel X-ray optics developed within the AHEAD2020 project T2 - DGaO-Proceedings N2 - 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. KW - X-ray KW - optics KW - telescope KW - Lobster Eye KW - mirror KW - Röntgenoptik Y1 - 2025 UR - https://www.dgao-proceedings.de/download/126/126_p5.pdf SN - 1614-8436 VL - 2025 IS - 126 SP - 1 EP - 2 PB - DGaO 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 - 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 -