@inproceedings{DoehringProbstStollenwerketal.2017, author = {D{\"o}hring, Thorsten and Probst, Anne-Catherine and Stollenwerk, Manfred and Emmerich, Florian and Stehl{\´i}kov{\´a}, Veronika and Inneman, Adolf}, title = {Prototyping iridium coated mirrors for X-ray astronomy}, series = {Proceedings of the International Society for Optics and Photonics}, volume = {2017}, booktitle = {Proceedings of the International Society for Optics and Photonics}, number = {10235}, editor = {Hudec, Ren{\´e} and Pina, Ladislav}, publisher = {SPIE International Society for Optics and Photonics}, address = {Bellingham WA}, organization = {Hochschule Aschaffenburg}, doi = {10.1117/12.2265931}, pages = {1023504-1 -- 1023504-8}, year = {2017}, abstract = {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.}, subject = {Iridium}, language = {en} } @inproceedings{StehlikovaUrbanNentvichetal.2017, author = {Stehlikova, Veronika and Urban, Martin and Nentvich, Ondrej and Inneman, Adolf and D{\"o}hring, Thorsten and Probst, Anne-Catherine}, title = {Study of lobster eye optics with iridium coated X-ray mirrors for a rocket experiment}, 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 = {10235}, editor = {Hudec, Rene}, publisher = {SPIE International Society for Optics and Photonics}, address = {Bellingham WA}, organization = {Czech Technical University in Prague}, doi = {10.1117/12.2265769}, pages = {1023505-1 -- 1023505-7}, year = {2017}, abstract = {In the field of astronomical X-ray telescopes, different types of optics based on grazing incidence mirrors can be used. This contribution describes the special design of a lobster-eye optics in Schmidt's arrangement, which uses dual reflection to increase the collecting area. The individual mirrors of this wide-field telescope are made of at silicon wafers coated with reflecting iridium layers. This iridium coatings have some advantages compared to more common gold layers as is shown in corresponding simulations. The iridium coating process for the X-ray mirrors was developed within a cooperation of the Aschaffenburg University of Applied Sciences and the Czech Technical University in Prague. Different mirror parameters essential for a proper function of the X-ray optics, like the surface microroughness and the problematic of a good adhesion quality of the coatings were studied. After integration of the individual mirrors into the final lobster-eye optics and the corresponding space qualification testing it is planned to fly the telescope in a recently proposed NASA rocket experiment.}, subject = {Iridium}, language = {en} } @misc{SpeitWolffDoehring2017, author = {Speit, Burkard and Wolff, Silke and D{\"o}hring, Thorsten}, title = {LEAD-CONTAINING RADIATION RESISTANT GLASS AND MANUFACTURING THE SAME}, year = {2017}, abstract = {PROBLEM TO BE SOLVED: To provide a radiation resistant glass having radiation resistance and high transparency.SOLUTION: There is provided a radiation resistant glass containing, by wt.\%, the following components: SiO of 12 to 45, BO of 0 to 4, AlO of 0 to 4, TiO of 0 to 5, PbO of 50 to 82, NaO of 0 to 4, KO of 0 to 8, and at least 3 doping agents selected from a group consisting of CeO, MoO, BiO, WO, AgO, SnO, SbO and AsO where the total of these doping agents are at least at 0.1 wt.\% and the weight percentage of AsO is 0 to <0.2\%.}, subject = {Glas}, language = {mul} } @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} } @inproceedings{DoehringProbstStehlikovaetal.2017, author = {D{\"o}hring, Thorsten and Probst, Anne-Catherine and Stehlikova, Veronika and Skala, Petr and Inneman, Adolf and Hudec, Rene}, title = {JEUMICO - Bayerisch-tschechische Kooperation zur Entwicklung von R{\"o}ntgenteleskopen}, series = {DGaO-Proceedings}, volume = {2017}, booktitle = {DGaO-Proceedings}, number = {2017}, publisher = {DGaO}, organization = {Hochschule Aschaffenburg}, issn = {1614-8436}, pages = {2}, year = {2017}, abstract = {Das Projekt JEUMICO wird vom Projekttr{\"a}ger BAYHOST im Rahmen eines Programms f{\"u}r bilaterale wissenschaftliche Projekte zwischen Tschechien und Bayern gef{\"o}rdert. Inhaltlich werden von der Hochschule Aschaffenburg und der Technischen Universit{\"a}t Prag hier gemeinsam R{\"o}ntgenoptiken f{\"u}r ein geplantes astronomisches Experiment an Bord einer NASA-H{\"o}henrakete entwickelt.}, subject = {R{\"o}ntgenstrahlung}, language = {de} } @inproceedings{HudecDoehringRemisova2017, author = {Hudec, Rene and D{\"o}hring, Thorsten and Remisova, Katerina}, title = {Lobster Eye Optics \& Biomimetics}, series = {DGaO-Proceedings}, volume = {2017}, booktitle = {DGaO-Proceedings}, number = {2017}, publisher = {DGaO}, organization = {Czech Academy of Sciences}, issn = {1614-8436}, pages = {2}, year = {2017}, abstract = {We present optic designs based on biomimetic, namely technical applications of animal eyes principles (here: Lobster Eyes) for the special application of wide field X-ray imaging. Thereby we show and discuss some experimental results and correlate them with simulations. Preliminary results of an ongoing study on other strange animal mirror eyes with potential scientific and technical applications are also discussed. Some of them are based on the principle of multilayer multi-mirror active optics arrangements. The Lobster Eye X-ray optics needs special reflective coatings for a better performance, which are currently developed within the Bavarian-Czech cooperation project JEUMICO.}, subject = {R{\"o}ntgenastronomie}, language = {en} } @inproceedings{SkalaDoehringHudec2017, author = {Skala, Petr and D{\"o}hring, Thorsten and Hudec, Rene}, title = {Colors of the universe - market study on optical filters for professional astronomy}, series = {DGaO-Proceedings}, volume = {2017}, booktitle = {DGaO-Proceedings}, number = {2017}, publisher = {DGaO}, organization = {Czech Technical University in Prague}, issn = {1614-8436}, pages = {2}, year = {2017}, abstract = {For astronomers, filters are essential observational tools and in many cases, it is hard for them to find the best supplier. We present list of filters manufacturers and their capabilities sorted and discussed.}, subject = {Markt{\"u}bersicht}, language = {en} } @article{HudecDoehring2017, author = {Hudec, Rene and D{\"o}hring, Thorsten}, title = {JEUMICO: Czech-Bavarian astronomical X-ray optics project}, series = {Contributions of the Astronomical Observatory Skalnat{\´e} Pleso}, volume = {2017}, journal = {Contributions of the Astronomical Observatory Skalnat{\´e} Pleso}, number = {47}, editor = {Slovak Academy of Sciences Astronomical Institute,}, pages = {170 -- 177}, year = {2017}, abstract = {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. Corresponding mirror segments use substrates of at silicon wafers which are coated with thin iridium � lms, as this material is promising high re ectivity in the X-ray range of interest. The sputtering parameters are optimized in the context of the expected re ectivity 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.}, subject = {Iridium}, language = {en} } @inproceedings{Doehring2017, author = {D{\"o}hring, Thorsten}, title = {Critical discussion on the UV absorption properties of Earth's atmosphere}, series = {Proceedings of SPIE}, volume = {2017}, booktitle = {Proceedings of SPIE}, number = {10453}, publisher = {SPIE}, organization = {Hochschule Aschaffenburg}, doi = {10.1117/12.2271645}, pages = {104530I-1 -- 104530I-10}, year = {2017}, abstract = {Sun´s ultraviolet radiation is classified into UV-A, UV-B, and UV-C bands. Thereby UV-A passes through Earth´s atmosphere, while UV-B is partially absorbed by ozone. The limitations of the commonly accepted statement, that UV-C is always completely absorbed by Earth´s atmosphere, are discussed critically. Below 200 nm the solar spectrum is strongly absorbed by molecular oxygen. The stratospheric ozone layer has strong absorption between 200 nm and 300 nm. However, the "ozone hole" increases UV-B radiation just below 300 nm and may also open a transmitting atmospheric window for harmful UV-C at the overlap region between oxygen absorption and ozone absorption.}, subject = {Ozonloch}, 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} }