@inproceedings{GhigoCitterioMazzolenietal.2004, author = {Ghigo, Mauro and Citterio, Oberto and Mazzoleni, Francesco and Pareschi, Giovanni and Aschenbach, Bernd and Br{\"a}uninger, Heinrich W. and Friedrich, Peter and Hasinger, G{\"u}nther and D{\"o}hring, Thorsten and Esemann, Hauke and Jedamzik, Ralf and H{\"o}lzel, Eva and Parodi, Giancarlo}, title = {The manufacturing of the XEUS x-ray glass segmented mirrors: status of the investigation and last results}, series = {Proceedings of SPIE}, volume = {5168}, booktitle = {Proceedings of SPIE}, pages = {180 -- 195}, year = {2004}, subject = {Spiegelteleskop}, language = {en} } @inproceedings{PareschiCivitaniSironietal.2019, author = {Pareschi, Giovanni and Civitani, Marta Maria and Sironi, Giorgia and Yang, Yang and Cotroneo, Vincenzo and Valsecchi, Giuseppe and Magagnin, Luca and D{\"o}hring, Thorsten and Bradshaw, Miranda and Burwitz, Vadim and Pelliciari, Carlo}, title = {Reflectivity-enhancement at low x-ray energies in astronomical telescopes using low-density overcoatings: alternative materials and deposition methods}, series = {Proceedings of SPIE}, volume = {2019}, booktitle = {Proceedings of SPIE}, number = {11119}, publisher = {SPIE}, organization = {Osservatorio Astronomico di Brera}, doi = {https://doi.org/10.1117/12.2532392}, pages = {11119OS-1 -- 11119OS-13}, year = {2019}, abstract = {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.}, subject = {R{\"o}ntgenteleskop}, language = {en} } @inproceedings{CotroneoBruniDoehringetal.2021, author = {Cotroneo, Vincenzo and Bruni, Ricardo and D{\"o}hring, Thorsten and Ferreira, Desiree and Gibertini, Eugenio and Henriksen, Peter and Magagnin, Luca and Massahi, Sonny and Pareschi, Giovanni and Romaine, Suzanne and Sethares, Leandra and Sironi, Giorgia and Spiga, Daniele and Tagliaferri, Gianpiero and Valsecchi, Giuseppe}, title = {Development of low-density coatings for soft x-ray reflectivity enhancement for ATHENA and other missions}, series = {Proceedings of SPIE}, volume = {2021}, booktitle = {Proceedings of SPIE}, number = {11852}, publisher = {SPIE}, organization = {Osservatorio Astronomico di Brera}, doi = {https://doi.org/10.1117/12.2599803}, pages = {118524P-1 -- 118524P-13}, year = {2021}, abstract = {Metallic coatings made of precious metals (e.g. Ir, Pt or Au) with high atomic number Z have been traditionally employed at grazing incidence for X-rays reflection and focalization. These materials offer a range of reflection extended to higher energies, but also present a series of absorption edges, which limit the reflectivity in the 2-4 keV band and below. Therefore the search for alternative coatings, able to improve the reflection in the soft energy range, is particularly relevant for the development of future telescopes, like ATHENA (ESA), Lynx (NASA) and eXTP (CAS). Low-Z overcoatings (e.g. carbon or B4C), applied on top of the high-Z metallic layer, can enhance the reflectivity in the softer band (mainly below 2 keV), but conventional deposition methods for these materials are not easily compatible with some of the mainstream technologies for mirror fabrication (notably, the silicon pore optics that will be used for the ATHENA X-ray mission which is being implemented by ESA). In this work we discuss novel solutions (carbon-like overcoatings realized by dip coating or vapor phase deposition), which can be particularly convenient for the application to ATHENA and to future telescopes.}, subject = {R{\"o}ntgenteleskop}, language = {en} } @inproceedings{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 Proceedings}, volume = {2021}, booktitle = {DGaO Proceedings}, number = {122}, publisher = {DGaO}, organization = {TH Aschaffenburg}, issn = {1614-8436}, pages = {1 -- 2}, year = {2021}, abstract = {High reflectivity grazing incidence mirrors of astronomical X-ray telescopes are usually coated with thin layers of iridium, gold, or platinum. Due to a series of absorption edges, these noble metals have low reflectivity in the 2 - 4 keV band. We present the development of innovative material combinations using chromium and an additional layer of polydopamine for enhanced reflectivity X-ray coatings.}, subject = {R{\"o}ntgenteleskop}, language = {en} } @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} } @inproceedings{RivoltaBassoCivitanietal.2022, author = {Rivolta, Giocomo and Basso, Stefano and Civitani, Marta and Cotroneo, Vincenzo and D{\"o}hring, Thorsten and Michler, Willy-Leopold and Pareschi, Giovanni and Spiga, Daniele and Stollenwerk, Manfred}, title = {Upgrade of a laboratory X-ray diffractometer to extend its operating range towards soft energies}, series = {Proceedings of SPIE}, volume = {2022}, booktitle = {Proceedings of SPIE}, number = {12181}, publisher = {SPIE}, organization = {Osservatorio Astronomico di Brera}, issn = {0277-786X}, doi = {doi: 10.1117/12.2629940}, pages = {121814S-1 -- 121814s-7}, year = {2022}, abstract = {The optical properties of X-ray mirror samples are commonly measured using diffractometers based on laboratory sources; like the Bede D1 diffractometer operating at INAF-OAB. This instrument can generate a collimated X-ray beam up to 60 keV, even though the most interesting energy region for x-ray astronomy applications is usually below 10 keV. In the softest part of this range (below 6 keV), high X-ray absorption in air hinders a full and precise characterization of optical components. In this work, we present an upgrade of the Bede D1 diffractometer that extends the operative range of the instrument below 6 keV; this is done by maximizing the flux at lowest energies and by reducing absorption by means of a helium-rich atmosphere. The upgraded instrument will be used for the tests of X-ray mirrors with innovative soft X-ray coatings, with potential application to the next generation X-ray telescopes (such as ATHENA and eXTP).}, subject = {R{\"o}ntgenspiegel}, language = {en} }