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    Multilayer X-Ray Optics for Future Missions
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    Keywords:
    X-ray telescope
    X-ray optics
    Spectral resolution
    X-Ray Astronomy
    Field of view
    Lightweight X-ray Wolter optics with a high angular resolution will enable the next generation of X-ray telescopes in space. The International X-ray Observatory (IXO) requires a mirror assembly of 3 m2 effective area (at 1.5 keV) and an angular resolution of 5 arcsec. These specifications can only be achieved with a novel technology like Silicon Pore Optics, which is developed by ESA together with a consortium of European industry. Silicon Pore Optics are made of commercial Si wafers using process technology adapted from the semiconductor industry. We present the manufacturing process ranging from single mirror plates towards complete focusing mirror modules mounted in flight configuration. The performance of the mirror modules is tested using X-ray pencil beams or full X-ray illumination. In 2009, an angular resolution of 9 arcsec was achieved, demonstrating the improvement of the technology compared to 17 arcsec in 2007. Further development activities of Silicon Pore Optics concentrate on ruggedizing the mounting system and performing environmental tests, integrating baffles into the mirror modules and assessing the mass production.
    X-ray optics
    X-ray telescope
    Active optics
    X-Ray Astronomy
    Citations (1)
    The immediate future for X-ray astronomy is the need for high sensitivity, requiring large apertures and collecting areas, the newly combined NASA, ESA and JAXA mission IXO (International X-ray Observatory) is specifically designed to meet this need. However, looking beyond the next decade, there have been calls for an X-ray space telescope that can not only achieve this high sensitivity, but could also boast an angular resolution of 0.1 arc-seconds, a factor of five improvement on the Chandra X-ray Observatory. NASA's proposed Generation-X mission is designed to meet this demand; it has been suggested that the X-ray optics must be active in nature in order to achieve this desired resolution. The Smart X-ray Optics (SXO) project is a UK based consortium looking at the application of active/adaptive optics to both large and small scale devices, intended for astronomical and medical purposes respectively. With Generation-X in mind, an active elliptical prototype has been designed by the SXO consortium to perform point-to-point X-ray focussing, while simultaneously manipulating its optical surface to improve its initial resolution. Following the completion of the large scale SXO prototype, presented is an overview of the production and operation of the prototype, with emphasis on the X-ray environment and preliminary results.
    X-ray telescope
    X-ray optics
    Active optics
    X-Ray Astronomy
    Orbital mechanics
    Citations (12)
    Multilayers have a great potentiality to improve the image quality, spectral resolution and energy coverage of x-ray optical systems. The angular resolution of a normal incidence telescope aims at approaching the diffraction limit in the soft x-ray region. Multilayer supermirror makes it possible to fabricate a grazing incidence telescope with high sensitivity in hard x-ray region. Multilayer coated gratings are also useful dispersive elements with high efficiency and spectral resolution in the 2-10keV region. The application of multilayers is expected to open up a new field in astronomical imaging and spectroscopic observations which are not accessible by present telescopes.
    X-ray telescope
    X-ray optics
    Spectral resolution
    Field of view
    X-Ray Astronomy
    Citations (0)
    Grazing incidence optics have been in use for quite some time for x-ray applications, including fusion research, synchrotron beam lines and x-ray astronomy. X-ray astronomy in particular has benefitted significantly from the development and performance improvements of large x-ray telescopes. Both high angular resolution and large collecting area are aimed at in the design and manufacturing. The x-ray telescope for the German ROSAT x-ray astronomy satellite mission has been finished and assembled with an unprecedented resolution of 3.3 arcsec for the half energy width of the point spread function and less than 3% scattering. A set of 3 light weight telescopes with an effective collecting area of 700 cm2 at 8 keV per telescope is being developed for the XMM mission of the European Space Agency using a nest of 58 thin wall Wolter type I systems. A review of the design, manufacturing and x-ray optical performance of both the ROSAT and XMM telescopes is presented.
    X-ray telescope
    X-ray optics
    ROSAT
    X-Ray Astronomy
    Observational astronomy
    Active optics
    Citations (1)
    There is a growing need for multiply nested large area X-ray mirrors with very fine angular resolution in future X-ray astrophysics experiments. Despite of promising results of several exploited technologies, it is not demonstrated yet that these technologies will provide the required angular resolutions of order of few arcsec. The alternative approach described in this paper is the method of active X-ray optics. In addition, active approaches based on computer control may be applied directly during manufacturing of advanced X-ray optics elements. We propose these methods as an alternative for the IXO project recently under study by ESA/NASA/JAXA.
    X-ray optics
    X-ray telescope
    Active optics
    X-Ray Astronomy
    Physical optics
    Citations (6)
    The ATHENA X-ray observatory is a large-class ESA approved mission, with launch scheduled in 2028. The technology of silicon pore optics (SPO) was selected as baseline to assemble ATHENA's optic with more than 1000 mirror modules, obtained by stacking wedged and ribbed silicon wafer plates onto silicon mandrels to form the Wolter-I configuration. Even if the current baseline design fulfills the required effective area of 2 m2 at 1 keV on-axis, alternative design solutions, e.g., privileging the field of view or the off-axis angular resolution, are also possible. Moreover, the stringent requirement of a 5 arcsec HEW angular resolution at 1 keV entails very small profile errors and excellent surface smoothness, as well as a precise alignment of the 1000 mirror modules to avoid imaging degradation and effective area loss. Finally, the stray light issue has to be kept under control. In this paper we show the preliminary results of simulations of optical systems based on SPO for the ATHENA X-ray telescope, from pore to telescope level, carried out at INAF/OAB and DTU Space under ESA contract. We show ray-tracing results, including assessment of the misalignments of mirror modules and the impact of stray light. We also deal with a detailed description of diffractive effects expected in an SPO module from UV light, where the aperture diffraction prevails, to X-rays where the surface diffraction plays a major role. Finally, we analyze the results of X-ray tests performed at the BESSY synchrotron, we compare them with surface finishing measurements, and we estimate the expected HEW degradation caused by the X-ray scattering.
    X-ray optics
    X-ray telescope
    Active optics
    Citations (11)
    Lightweight X-ray Wolter optics with a high angular resolution will enable the next generation of X-ray telescopes in space. The candidate mission ATHENA (Advanced Telescope for High Energy Astrophysics) required a mirror assembly of 1 m2 effective area (at 1 keV) and an angular resolution of 10 arcsec or better. These specifications can only be achieved with a novel technology like Silicon Pore Optics, which is being developed by ESA together with a consortium of European industry. Silicon Pore Optics are made of commercial Si wafers using process technology adapted from the semiconductor industry. We present the recent upgrades made to the manufacturing processes and equipment, ranging from the manufacture of single mirror plates towards complete focusing mirror modules mounted in flight configuration, and results from first vibration tests. The performance of the mirror modules is tested at X-ray facilities that were recently extended to measure optics at a focal distance up to 20 m.
    X-ray optics
    X-ray telescope
    Active optics
    Optical telescope
    X-Ray Astronomy
    Citations (0)
    Next generation X-ray telescopes in the coming decades require optics with high angular resolution and large collecting area at a fixed cost and budget. X-ray optics, unlike traditional normal incidence optics in optical and infrared telescopes, require many times the polished surface area to obtain an equivalent collecting area due to the nature of glancing incidence optics necessary to reflect higher energy X-ray photons. The Next Generation X-ray Optics (NGXO) group at NASA Goddard Space Flight Center (GSFC) is developing a manufacturing process capable of producing sub 5 arc-second half-power diameter (HPD) angular resolution optics in the near term, with the long term goal of producing optics for an X-ray telescope in the next 10 years with sub 1 arc-second HPD angular resolution. By parallelizing the production, integration, and testing of X-ray mirrors in separate modules, thousands of precisely formed X-ray mirror segments are assembled into one Mirror Assembly (MA), lowering the cost per collecting area by orders of magnitude compared to previous X-ray telescopes with similar resolution like the Chandra X-ray Observatory. Novel uses of kinematic mounts, precision actuators, and epoxy fixes each X-ray mirror segment to the submicron level with the sufficient strength to survive rocket launch.
    X-ray optics
    X-ray telescope
    Active optics
    X-Ray Astronomy
    Citations (0)
    X-rays provide one of the few bands through which we can study the epoch of reionization, when the first galaxies, black holes and stars were born. To reach the sensitivity required to image these first discrete objects in the universe needs a major advance in X-ray optics. Generation-X (Gen-X) is currently the only X-ray astronomy mission concept that addresses this goal. Gen-X aims to improve substantially on the Chandra angular resolution and to do so with substantially larger effective area. These two goals can only be met if a mirror technology can be developed that yields high angular resolution at much lower mass/unit area than the Chandra optics, matching that of Constellation-X (Con-X). We describe an approach to this goal based on active X-ray optics that correct the mid-frequency departures from an ideal Wolter optic on-orbit. We concentrate on the problems of sensing figure errors, calculating the corrections required, and applying those corrections. The time needed to make this in-flight calibration is reasonable. A laboratory version of these optics has already been developed by others and is successfully operating at synchrotron light sources. With only a moderate investment in these optics the goals of Gen-X resolution can be realized.
    X-ray optics
    X-ray telescope
    X-Ray Astronomy
    Active optics
    Physical optics
    Citations (5)
    The Slumped Glass Optics technology, developed at INAF/OAB since a few years, is becoming a competitive solution for the realization of the future X-ray telescopes with a very large collecting area, as e.g. the proposed Athena, with more than 2 m2 effective area at 1 keV and with a high angular resolution (5'' HEW). The developed technique is based on modular elements, named X-ray Optical Units (XOUs), made of several layers of thin foils of glass, previously formed by direct hot slumping in cylindrical configuration, and then stacked in a Wolter-I configuration, through interfacing ribs. The achievable global angular resolution of the optics relies on the surface shape accuracy of the slumped foils, on the smoothness of the mirror surfaces and on the correct integration and co-alignment of the mirror segments achieved with a dedicated Integration Machine (IMA). In this paper we provide an update of the project development, reporting on the last results achieved. In particular, we will present the results obtained with full illumination X-ray tests for the last developed prototypes.
    Interfacing
    X-ray optics
    Soft X-rays
    Citations (5)