@article{CotroneoBassoCivitanietal.2025, author = {Cotroneo, Vicenzo and Basso, Stefano and Civitani, Marta and D{\"o}hring, Thorsten and Gibertini, Eugenio and Iovenitti, Simone and Magagnin, Luca and Pareschi, Giovanni and Sironi, Giorgia and Spiga, Daniele and Tagliaferri, Gianpiero and Valsecchi, Giuseppe}, title = {Polydopamine Coatings for Enhanced Soft X-Ray Reflectivity in Space Telescope Mirrors}, series = {ECS Meeting Abstracts}, volume = {MA2025-02}, journal = {ECS Meeting Abstracts}, number = {67}, publisher = {The Electrochemical Society}, issn = {2151-2043}, doi = {10.1149/MA2025-02673247mtgabs}, pages = {3247 -- 3247}, year = {2025}, abstract = {It has been known for years that sputtered low-density coatings deposited under vacuum (e.g. carbon or B4C), applied on top of high-density metallic coatings, can enhance their reflectivity in the soft X-ray band (below ~5 keV). However, the physical deposition techniques, as vacuum-based sputtering, to produce B4C or amorphous coatings are usually difficult and highly costing. Polydopamine (PDA), a bio-polymer inspired by mussels, exhibits exceptional surface binding and it's nowadays a popular material used in surface engineering for multipurpose applications (Ryu, 2018). PDA thin film are typically produced in aqueous solution by the oxidative polymerization of dopamine, commonly known as one of the "hormones of happiness", resulting in nanometric PDA coating with tunable thickness and morphology. In recent years, we have introduced and investigated a novel and scalable strategy for enhancing the soft X-ray reflectivity of telescope mirrors used in space missions based on dip-liquid deposition of PDA thin films as carbon-rich coating (carbon 62.7 \%wt. in DA monomer) (Cotroneo, 2022). This method is very versatile and quick and offers a low-cost alternative to conventional carbon-like coating, while maintaining or even exceeding performance in the energy range below ~5 keV. Experimental tests across three X-ray beamlines—including two synchrotron facilities—demonstrated consistent reflectivity enhancement, especially in the 1-4 keV energy range and with a good match between theoretical predictions and experimental reflectivity profiles. When applied over traditional coatings (e.g Au, Ir), the dip-liquid overcoats produced improvements of up to 100\% in effective area for some specific X-ray bands compared to conventional single-metal films. These results are particularly compelling for nickel-replicated mirrors with gold coatings, a common architecture in cost-sensitive space missions. Bibliography Cotroneo, V., 2022. Dopamine dip-liquid overcoatings for soft x-ray reflectivity enhancement. SPIE Proceedings. Ryu, J. H., 2018. Polydopamine Surface Chemistry: A Decade of Discovery. ACS Applied Materials \& Interfaces.}, subject = {R{\"o}ntgenteleskop}, language = {en} } @inproceedings{DoehringKrivanekovaHildenbrand2025, author = {D{\"o}hring, Thorsten and Krivanekova, Lucia and Hildenbrand, Georg}, title = {ASTRABAX - Scientific results of two stratospheric balloon flights}, series = {18th Pico- and Nanosatellite Workshop 2025, Abstracts Book}, volume = {2025}, booktitle = {18th Pico- and Nanosatellite Workshop 2025, Abstracts Book}, publisher = {Julius-Maximilians-Universit{\"a}t W{\"u}rzburg}, address = {W{\"u}rzburg}, organization = {TH Aschaffenburg}, pages = {17 -- 17}, year = {2025}, abstract = {The ASTRABAX experiment ("Aschaffenburg Stratospheric Balloon Experiment") uses a multimodal platform to study radiation exposures in the upper atmosphere. We present a modular approach to accommodate the numerous setups under the weight restriction of light unmanned free stratospheric balloon. The compartmental setup allows flexibility to address current research questions with low expenditure in costs, manpower and technology expertise. Its easy implementation is suitable for educational purposes of students in the fields of astronomy, astrobiology, and material research. Recently, two stratospheric balloons were flown to test the feasibility and connectivity of different building blocks in a temperature-controlled gondola, and to characterize the stratospheric radiation environment.The focus of the physical experiments is the observation of the UV-C spectral region using miniature UV-VIS spectrometers, and cosmic ray dosimetry with a Geiger counter. A second set of experiments assesses the effects of irradiation on polydopamine coatings intended for the application in space-born X-ray telescopes. The platform also contains samples of biological cells that are simultaneously exposed to low-dose radiation of different compositions of particle, X-ray and UV radiation. Post-flight nanoscopic measurements aim to examine changes in the spatial chromatin organization playing a crucial role in DNA-repair mechanisms. Investigations in such natural environment are of importance for high altitude atmospheric as well as space flights, for comparable exposures on other objects of the solar system and for astrobiology.}, subject = {Stratosph{\"a}ren-Ballon}, language = {en} } @misc{DoehringPreglerKrivanekovaetal.2025, author = {D{\"o}hring, Thorsten and Pregler, Jan and Krivanekova, Lucia and Hildenbrand, Georg}, title = {Strahlungsmessungen beim Erstflug des Stratosph{\"a}renballon-Experiments ASTRABAX}, series = {DGaO-Proceedings}, volume = {2025}, journal = {DGaO-Proceedings}, number = {126}, publisher = {DGaO}, organization = {TH Aschaffenburg}, pages = {1 -- 2}, year = {2025}, abstract = {Mit dem Aschaffenburger Stratosph{\"a}ren-Ballon-Experiment („ASTRABAX") werden Experimente zu Material- und Biowissenschaften unter extremer Strahlungsexposition in großer H{\"o}he durchgef{\"u}hrt. Der erste von drei geplanten Ballonfl{\"u}gen startete Mitte Oktober 2024 im norddeutschen Bad Pyrmont und erreichte eine Flugh{\"o}he von fast 35 km. Der Schwerpunkt der physikalischen Experimente lag auf der Vermessung des UV-C-Spektralbereichs mit einem Miniatur-UV-VIS-Spektrometer und der Strahlungsdosimetrie mit einem Geigerz{\"a}hler. In einem zweiten Satz von Experimenten wurde die Wirkung der Bestrahlung auf Polydopaminproben untersucht, welche derzeit f{\"u}r Beschichtungen von astronomischen R{\"o}ntgenspiegel entwickelt werden. Die Ballongondel enthielt auch Proben biologischer Zellen, die hier gleichzeitig einer niedrig dosierten Strahlung von hochenergetischen Partikeln, Gammastrahlen und UV-Strahlung ausgesetzt wurden. Experimente unter solchen nat{\"u}rlichen stratosph{\"a}rischen Bedingungen sind f{\"u}r atmosph{\"a}rische H{\"o}henfl{\"u}ge, bemannte Raumfahrtmissionen, vergleichbare Expositionen bei anderen Objekten des Sonnensystems und die strahlenbiologische Forschung von Bedeutung.}, subject = {Stratosph{\"a}ren-Ballon}, language = {de} } @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} } @inproceedings{CotroneoBruniCivitanietal.2022, author = {Cotroneo, Vincenzo and Bruni, Ricardo and Civitani, Marta Maria and D{\"o}hring, Thorsten and Gibertini, Eugenio and Magagnin, Luca and Pareschi, Giovanni and Rivolta, Giacomo and Romaine, Suzanne and Sethares, Leandra and Sironi, Giorgia and Tagliaferri, Gianpiero and Valsecchi, Giuseppe}, title = {Dopamine dip-liquid overcoatings for soft X-ray reflectivity enhancement}, series = {Proceedings of SPIE}, volume = {2022}, booktitle = {Proceedings of SPIE}, number = {12181}, doi = {10.1117/12.2630212}, pages = {1218117 -- 1218117}, year = {2022}, abstract = {It has been known for some time that sputtered low-density coatings deposited under vacuum (e.g. carbon or B4C), applied on top of high-density metallic coatings, can enhance the reflectivity in the soft x-ray band (below ~5 keV). In the last years, we experimented with novel carbonated coatings obtained by dip-liquid deposition, in which a thin film is formed on the surface of a mirror by immersion in a suitable precursor solution. After several attempts with different chemical compounds, we found an optimal candidate both for the reflectivity performance and for the convenience of the deposition process, which is much simpler and inexpensive compared to conventional processes. In particular, such coatings can enhance the soft x-ray response at the reflection angles employed in future telescopes, like ATHENA (ESA), Lynx (NASA) and eXTP (CAS). In this paper we consider the application of dip-liquid overcoatings on conventional coatings (Au, Ir) or in combination with recently proposed chromium overcoatings and their possible uses to enhance the reflectivity of x-ray mirrors at low, medium or higher energies, presenting the first experimental results of x-ray tests on these coatings.}, subject = {R{\"o}ntgenspiegel}, 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 = {EPJ Web of Conferences}, volume = {266 (2022)}, booktitle = {EPJ Web of Conferences}, doi = {10.1051/epjconf/202226613010}, pages = {1 -- 2}, 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 = {de} }