@article{StieglitzBurwitzDoehringetal.2022, author = {Stieglitz, Veronika and Burwitz, Vadim and D{\"o}hring, Thorsten and Hudec, Rene and Vitek, Stanislav}, title = {Design and testing of a Kirkpatrick-Baez optics variation}, series = {EPJ Web of Conferences}, volume = {266 (2022)}, journal = {EPJ Web of Conferences}, doi = {10.1051/epjconf/202226603021}, pages = {1 -- 2}, year = {2022}, abstract = {Beside Wolter I X-ray optics, which are used at most in currently operating X-ray space telescopes, there exist also other optical designs and their usability for space observations is still the matter of studies. This article covers preliminary testing results of an optical module which is based on a modified Kirkpatrick-Baez optics. This X-ray optics, consisting of four sub-modules, was assembled in Prague and tested at the PANTER test facility of MPE afterward. The sub-modules use different reflective coatings, in part developed by our research group, on complementary flat mirrors, which approximate the shape of a Kirkpatrick-Baez optical design. In this contribution we summarise the design of the optical modules, the details of applied coating layers, and the X-ray characterisation results at the PANTER test facility}, subject = {R{\"o}ntgenoptik}, language = {en} } @inproceedings{DoehringZeisingStieglitzetal.2022, author = {D{\"o}hring, Thorsten and Zeising, Sebastian and Stieglitz, Veronika and Burwitz, Vadim and Rukdee, Surangkhana and Friedrich, Peter and Jelinek, Martin and Hudec, Rene}, title = {R{\"o}ntgenteleskop-Funktionstests durch Beobachtung astronomischer Objekte am sichtbaren Nachthimmel}, series = {DGaO Proceedings}, volume = {2022}, booktitle = {DGaO Proceedings}, publisher = {DGaO}, organization = {TH Aschaffenburg}, issn = {1614-8436}, pages = {1 -- 2}, year = {2022}, abstract = {Lobster-Eye-R{\"o}ntgenteleskope nutzen reflektierende Planspiegel unter streifendem Einfall und zeichnen sich durch ein großes Beobachtungsfeld aus. Die Spiegel reflektieren auch sichtbare Strahlung hervorragend. Nach R{\"o}ntgen-messungen im Labor wurden nun weitere Tests durchgef{\"u}hrt, um die Abbildungs-eigenschaften mit realen Objekten des sichtbaren Himmels zu untersuchen.}, subject = {R{\"o}ntgenteleskop}, language = {de} } @inproceedings{DoehringRoedlingKimmeletal.2021, author = {D{\"o}hring, Thorsten and R{\"o}dling, Claudius and Kimmel, Kevin and Zeising, Sebastian and Stadtm{\"u}ller, Johannes and Stollenwerk, Manfred and Verma, Shruti and Rees, Paul}, title = {Optical characterization of reflective coatings for astronomical telescope mirrors}, series = {DGaO Proceedings}, volume = {2021}, booktitle = {DGaO Proceedings}, number = {122}, publisher = {DGaO}, organization = {TH Aschaffenburg}, issn = {1614-8436}, pages = {1 -- 1}, year = {2021}, abstract = {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.}, subject = {Spiegelteleskop}, language = {en} } @inproceedings{DoehringStieglitzBurwitzetal.2021, author = {D{\"o}hring, Thorsten and Stieglitz, Veronika and Burwitz, Vadim and Hartner, Gisela and M{\"u}ller, Thomas and Schmidt, Thomas and Rukdee, Surangkhana and Friedrich, Peter and Sahin, Fatih and Hudec, Rene}, title = {Charakterisierung von Weitwinkel-R{\"o}ntgenteleskopen in der Testanlage PANTER}, series = {DGaO Proceedings}, volume = {2021}, booktitle = {DGaO Proceedings}, number = {122}, publisher = {DGaO}, organization = {TH Aschaffenburg}, issn = {1614-8436}, pages = {1 -- 2}, year = {2021}, abstract = {Im Rahmen einer bayerisch-tschechischen Kooperation entstanden zwei R{\"o}ntgenteleskope, best{\"u}ckt mit Gold- und Iridium-beschichteten Planspiegeln. Deren Charakterisierung erfolgte an der R{\"o}ntgentestanlage PANTER, welche parallel auf die Teleskope einfallendes Sternenlicht simuliert. Die Teleskope haben eine Winkelaufl{\"o}sung von ca. 4 Bogenminuten und eine Brennweite von rund 2 Metern.}, subject = {R{\"o}ntgenteleskop}, language = {de} } @misc{DoehringRoedlingKimmeletal.2021, author = {D{\"o}hring, Thorsten and R{\"o}dling, Claudius and Kimmel, Kevin and Zeising, Sebastian and Stadtm{\"u}ller, Johannes and Stollenwerk, Manfred and Verma, Shruti and Rees, Paul}, title = {Optical characterization of reflective coatings for astronomical telescope mirrors}, series = {DGaO Jahrestagung}, volume = {2021}, journal = {DGaO Jahrestagung}, organization = {TH Aschaffenburg}, pages = {1 -- 1}, year = {2021}, abstract = {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.}, subject = {Spiegelteleskop}, language = {en} } @misc{DoehringStieglitzBurwitzetal.2021, author = {D{\"o}hring, Thorsten and Stieglitz, Veronika and Burwitz, Vadim and Hartner, Gisela and M{\"u}ller, Thomas and Schmidt, Thomas and Rukdee, Surangkhana and Friedrich, Peter and Sahin, Fatih and HUdec, Rene}, title = {Charakterisierung von Weitwinkel-R{\"o}ntgenteleskopen in der Testanlage PANTER}, series = {DGaO Jahrestagung}, volume = {2021}, journal = {DGaO Jahrestagung}, organization = {TH Aschaffenburg}, pages = {1 -- 1}, year = {2021}, abstract = {Im Rahmen einer bayerisch-tschechischen Kooperation entstanden zwei mechanisch baugleiche R{\"o}ntgenteleskope, best{\"u}ckt mit Gold- und Iridium-beschichteten Planspiegeln. Die Charakterisierung der nach dem {\"a}gyptischen Gott HORUS benannten Teleskope erfolgte an der R{\"o}ntgentestanlage PANTER des Max-Plack-Instituts f{\"u}r extraterrestrische Physik. Diese Vakuum-Testanlage simuliert parallel auf die Teleskope einfallendes Sternenlicht, wobei hier die Strahlung aus einer R{\"o}ntgenquelle in 120 Metern Abstand stammt. Die Messungen selbst fanden in einer daran angebauten 12 Meter langen Testkammer von 3,5 Metern Durchmesser statt. Im M{\"a}rz 2021 sahen die HORUS-Teleskope zum erstem Mal R{\"o}ntgenlicht. W{\"a}hrend der Testkampagne von ca. 54 Stunden Dauer wurden 536 Einzelmessungen an den beiden Teleskopen durchgef{\"u}hrt, bei denen Photonenenergien und Einfallswinkel variiert wurden. Von einer empfindlichen CCD-Kamera, einem Prototyp der eROSITA-Satellitenkamera, wurden hierbei insgesamt 11.153.574 R{\"o}ntgenphotonen individuell detektiert, analysiert und digital verarbeitet. Die beiden Weitwinkel-R{\"o}ntgenteleskope haben eine Winkelaufl{\"o}sung von circa 4 Bogenminuten und eine Brennweite von rund zwei Metern.}, subject = {R{\"o}ntgenstrahlung}, language = {de} } @misc{DoehringStadtmuellerStollenwerketal.2021, author = {D{\"o}hring, Thorsten and Stadtm{\"u}ller, Johannes and Stollenwerk, Manfred and Cotroneo, Vincenzo and Pareschi, Giovanni and Gibertini, Eugenio and Magagnin, Luca}, title = {Low-density coatings for enhanced X-ray reflectivity of astronomical telescope mirrors}, series = {DGaO Jahrestagung}, volume = {2021}, journal = {DGaO Jahrestagung}, organization = {TH Aschaffenburg}, pages = {1 -- 1}, year = {2021}, abstract = {X-ray telescopes usually operate in space and are quite different from astronomical telescopes for visible light. For normal angles of incidence, optical light is reflected on the mirror surface, whereas X-rays are either transmitted or absorbed. However, also high reflectivity X-rays mirrors are possible, when the incident rays direction is almost parallel to the mirror surface. Such grazing incidence mirrors are usually coated with thin layers of precious metals like iridium, gold or platinum, as this result in high X-ray reflectivity. These noble metals offer a wide range of reflection up to high photon energies, but, due to a series of absorption edges, have low reflectivity in the 2 - 4 keV band and below. This contribution presents the development of innovative material combinations based on thin layers of iridium and chromium, followed by an additional layer of carbon-based materials. We also discuss corresponding production methods (like dip coating) for enhanced reflectivity mirror coatings of future X-ray telescopes.}, subject = {R{\"o}ntgenstrahlung}, language = {en} } @misc{Doehring2021, author = {D{\"o}hring, Thorsten}, title = {Advanced Materials and Manufacturing Technologies for Space Applications}, series = {Proceedings of International Research Days}, volume = {2021}, journal = {Proceedings of International Research Days}, organization = {TH Aschaffenburg}, pages = {1}, year = {2021}, abstract = {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")}, subject = {Satellitentechnik}, language = {en} } @inproceedings{ProbstDoehringZeisingetal.2017, author = {Probst, Anne-Catherine and D{\"o}hring, Thorsten and Zeising, Sebastian and Salmaso, Bianca and Stollenwerk, Manfred and Proserpio, Laura}, title = {Challenges in metrology of mirror segments for X-ray telescopes}, series = {Proceedings of the 8th High Level Expert Meeting Asphere Metrology}, volume = {2017}, booktitle = {Proceedings of the 8th High Level Expert Meeting Asphere Metrology}, number = {8}, publisher = {UTOB e.V.}, address = {Braunschweig}, organization = {Hochschule Aschaffenburg}, pages = {4}, year = {2017}, abstract = {High angular resolution, large collecting area and reduced weight per unit area are required for astronomical X-ray telescopes of the next generation observatories. New technologies for processing X-ray mirrors are under development to fulfill these needs. One option is to realize a Wolter I type telescope constituted of several hundred nested thin and light-weight X-ray mirror segments. The individual mirror segments need to be coated with an about 100 nm thick film of a high-reflective material to enhance the reflectivity for X-rays. Thereby an accurate shape metrology of the segments is necessary to predict the angular resolution of the astronomical telescope as well as to control the development process of X-ray mirrors. We present the challenges in shape measurements of thin glasses used to control the coating process and first experimental results about the repeatability of the measurements.}, subject = {Spiegelteleskop}, language = {en} }