The LOBSTER telescopes are based on the optical arrangement of the lobster eye. The main difference from classical X-ray space telescopes in wide use is the very large field of view while the use of optics results in higher efficiency if compared with detectors without optics. Recent innovative technologies have enabled to design, to develop and to test first prototypes. They will provide deep sensitive survey of the sky in X-rays for the first time which is essential for both long-term monitoring of celestial high-energy sources as well as in understanding transient phenomena. The technology is now ready for applications in space.
The future space X-ray astronomy imaging missions require very large collecting areas at still fine angular resolution and reasonable weight. The novel space Xray optics substrates such as Silicon wafers and thin thermally formed glass enable wide applications of precise and very light weight (volume densities 2.3 to 2.5 gcm-3) optics. The recent status of novel technologies as well as developed test samples with emphasis on precise optical surfaces based on novel materials and their space applications will be presented and discussed.
The future space X-ray astronomy imaging missions require very large collecting areas at still fine angular resolution and reasonable weight. The novel substrates for X-ray mirrors such as Silicon wafers and thin thermally formed glass enable wide applications of precise and very light weight (volume densities 2.3 to 2.5 gcm-3) optics. The recent status of novel technologies as well as developed test samples with emphasis on precise optical surfaces based on novel materials and their space applications is presented and discussed.
The X-ray optics is a key element of various X-ray telescopes, X-ray microscopes, as well as other X-ray imaging instruments. The grazing incidence X-ray lenses represent the important class of X-ray optics. Most of grazing incidence (reflective) X-ray imaging systems used in astronomy but also in other (laboratory) applications are based on the Wolter 1 (or modified) arrangement. But there are also other designs and configurations proposed, used and considered for future applications both in space and in laboratory. The Kirkpatrick-Baez (K-B) lenses as well as various types of Lobster-Eye optics and MCP/Micropore optics serve as an example. Analogously to Wolter lenses, the X-rays are mostly reflected twice in these systems to create focal images. Various future projects in X-ray astronomy and astrophysics will require large segments with multiple thin shells or foils. The large Kirkpatrick-Baez modules, as well as the large Lobster-Eye X-ray telescope modules in Schmidt arrangement may serve as examples. All these space projects will require high quality and light segmented shells (bent or flat foils) with high X-ray reflectivity and excellent mechanical stability. The Multi Foil Optics (MFO) approach represent a promising alternative for both LE and K-B X-ray optical modules. Several types of reflecting substrates may be considered for these applications, with emphasis on thin float glass sheets and, more recently, high quality silicon wafers. This confirms the importance of non- Wolter X-ray optics designs for the future.
Future large space X-ray telescopes (such as IXO) require precise and light-weight X-ray optics based on numerous thin reflecting shells. Novel approaches and advanced technologies are to be exploited and developed. In this contribution, we refer on results of tested X-ray mirror shells produced by glass thermal forming (GTF) and by shaping Si wafers. Both glass foils and Si wafers are commercially available, have excellent surface microroughness of a few 0.1 nm, and low weight (the volume density is 2.5 g cm-3 for glass and 2.3 g cm-3 for Si). Technologies are needed to be exploited; how to shape these substrates to achieve the required precise Xray optics geometries without degradations of the fine surface microroughness. Although glass and recently silicon wafers are considered to represent most promising materials for future advanced large aperture space Xray telescopes, there also exist other alternative materials worth further study such as amorphous metals and glassy carbon [1]. In order to achieve sub-arsec angular resolutions, principles of active optics have to be adopted.
We report on recent progress with development of astronomical X-ray optics based on bent Si wafers. Recent efforts
with Si wafers have been focused on new forming technologies such as method of deposition of thin layers. The role of
substrates quality in performance of final mirror arrays, as required by large future space X-ray astronomy experiments
was also studied.
The ESA's invitation to participate in the innovative technology developments for the new space mission represents the
natural continuation of the efforts of the Czech team in development of innovative X-ray telescopes, focusing on
particular demands and requirements of a concrete project, with emphasis on fully new and light-weight technologies. In
this paper we focus on studying of other alternative materials such as SiC or glassy carbon, which could be considered as
suitable materials for the producing of precise light weight X-ray optics due to their physical and chemical properties and
so far successfully compete with more common materials (like glass or Si) as well as on Si wafers with improved surface
quality and analysis and evaluation of measured data.
We report on the continuation of the development of test samples of astronomical x-ray optics based on thermally
formed glass foils and on bent Si wafers. Experiments with thermal glass forming have continued adding wider range of
evaluated and optimized parameters including viscosity and internal stress analyses, as well as investigation of mounting
influences. Experiments with Si wafers focused on their quality improvements such as flatness and thickness uniformity
in order to better meet the requirements of future X-ray astronomy projects applications, as well as on study of their
surface quality, defects analysis, and methods for its reproducible measurement.
We report on recent progress with development of astronomical X-ray optics based on thermally formed glass foils
and on bent Si wafers. Experiments with thermal glass forming have continued adding wider range of evaluated
and optimized parameters. Recent efforts with Si wafers have been focused on their quality improvements such
as flatness and thickness uniformity in order to better meet the requirements of future X-ray astronomy projects
applications, as well as on study of their surface quality, defects analysis, and methods for its reproducible measurement.
The role of substrates quality in performance of final mirror arrays, as required by large future space X-ray astronomy
experiments was also studied.
A laboratory system with a crystal concentrator for focusing γ-rays has been developed. The facility has been
designed in particular for tests of diffraction systems based on small crystals in the Bragg and Laue configurations.
Two radioactive sources (Co-57 and Ba-133) are being used to cover the energy range from 30 to 400 keV. The
diffracted beam is detected using Germanium (HPGe) and CdZnTe detectors. We report on the preliminary
characterization of crystal mosaicities for different crystals.
Future space X-ray astronomy and astrophysics projects require accurate but light and high throughput multiple nested
X-ray optics. The Czech Republic started being the full member of ESA in November, 2008 and the participant in the
innovative technology developments for the new space mission represents the natural continuation of the efforts of the
Czech team in development of innovative X-ray telescopes, focusing on particular demands and requirements of a
concrete project, with emphasis on fully new and light-weight technologies. We will report not only on silicon or glass
but also on other alternative materials such as SiC or glossy carbon, which could be considered as suitable materials for
the producing of precise light weight X-ray optics due to their physical and chemical properties.
We report on recent progress with development of astronomical X-ray optics based on thermally formed glass foils
and on bent Si wafers. Experiments with thermal glass forming have continued adding wider range of evaluated
and optimized parameters. Recent efforts with Si wafers have been focused on their quality improvements such
as flatness and thickness uniformity in order to better meet the requirements of future X-ray astronomy projects
applications, as well as on study of their surface quality, defects analysis, and methods for its reproducible measurement.
The role of substrates quality in performance of final mirror arrays, as required by large future space X-ray astronomy
experiments was also studied. The problem of increasing size of Si wafers, required for some X-ray optics applications,
is also addressed. First results of irradiation tests of selected substrates are also reported and discussed.
The precisely shaped glass sheets and Si wafers are generally considered as the most promising substrates for future
large space astronomical X-ray telescopes. Both approaches have demonstrated promising results obtained in the
course of last years. In this contribution, we report on continued systematic efforts and analysis in precise shaping of
thin glass sheets as well as Si wafers. New results will be briefly presented and discussed. For Si wafers, recent
efforts focus also on improving the intrinsic quality of the slices to better meet the high requirements of future space
projects.
The thermally formed thin glass foils and optically shaped Si wafers are considered to belong to the most promising
technologies for future large space X-ray telescopes. We present and discuss the recent progress in these technologies, as
well as properties of test mirrors produced and tested. For both technologies, both flat and curved samples have been
produced and tested. The achieved profile accuracy is of order of 1 micrometer or better, while the bending technologies
maintain the intrinsic fine surface microroughness of substrates (better than 0.5 nm for glass and around 0.1 nm for Si
wafers).
The future large space X-ray telescopes in study (such as the ESAs XEUS) require novel approaches and innovative lightweight technologies. Although there are several alternative possibilities, in general the shaped thin glass foils and shaped Si wafers are considered to belong to the most promising ones. We present and discuss the recent progress in these technologies, as well as properties of test mirrors produced and tested. For both technologies, both flat and curved samples have been produced and tested. The achieved profile accuracy is of order of 1 micrometer or better, while the bending technologies maintain the intrinsic fine surface microroughness of substrates (better than 0.5 nm).
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