IXO x-ray mirrors based on slumped glass segments with reinforcing ribs: optical and mechanical design, image error budget, and optics unit integration process

Civitani, M.; Basso, S.; Bavdaz, Marcos; Citterio, O.; Conconi, P.; Gallieni, D.; Ghigo, M.; Guldimann, Benedikt; Martelli, Francesco; Pagano, G.; Pareschi, G.; Parodi, Giancarlo; Proserpio, L.; Salmaso, B.; Spiga, D.; Tagliaferri, G.; Tintori, Matteo; Wille, Eric; Zambra, A.

doi:10.1117/12.857197

Cited by 12 publications

(16 citation statements)

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“…The feasibility study was led by INAF/OAB and involved also MPE and a group of a few small industries (BCV Progetti, ADS International and MediaLario Technologies). Our approach is characterized by several innovative technical elements, often alternative to the methods investigated in the US, that concern the technology for the hot slumping of the glass segment and their integration to form XOU [5,6]. Despite the end of the contract, this development program is continued in order to verify which is the real limit of the technology.…”

Section: Introductionmentioning

confidence: 98%

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X-ray optical units made of glass: achievements and perspectives

et al. 2014

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Future X-ray telescopes with very large collecting area, like the proposed Athena with more than 2 m 2 effective area at 1 keV, need to be realized as assemblies of a large number of X-ray optical units, named X-ray Optical Units (XOUs). The Brera Astronomical Observatory (INAF-OAB) is developing a new technology to manufacture these modular elements, compatible with an angular resolution of 5 arcsec HEW (Half-Energy-Width). This technique consists in stacking in a Wolter-I configuration several layers of thin foils of glass, previously formed by direct hot slumping. The achievable global angular resolution of the optics relies on the required surface shape accuracy of slumped foils, on the smoothness of the mirror surfaces and on the correct integration and co-alignment of the mirror segments operated trough a dedicated Integration Machine (IMA). In this paper we provide an overview of the project development, reporting on the very promising results achieved so far, including in-focus full illumination X-ray tests of the prototype (Proof of Concept, POC#2, integrated at the beginning of 2013) for which an HEW of 22.1'' has been measured at Panter/MPE. Moreover we report on the on-going activities, with a new integrated prototype (PoC#3). X-ray test in pencil beam revealed that at least a segment between two external ribs is characterized by an HEW well below 10''. Lastly, the overall process up-grade to go from 20 m to 12m focal length (to be compatible with Athena+ configuration) is presented.

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Section: Introductionmentioning

confidence: 98%

“…The requirements used to define our development activities were compatibles with the proposed IXO X-ray telescope [6].…”

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confidence: 99%

X-ray optical units made of glass: achievements and perspectives

et al. 2014

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“…These can be fulfilled with a Wolter I telescope of 20-m focal length and comprising 350 mirror shells with a radius of curvature ranging from 0.3 to 1.7 m. The current design requires 16,560 glass mirror segments, stacked into basic modules (XOU) through the use of glass spacers between segments of consecutive coaxial shells (ribs) and comprising two glass elements (back and front planes) which gives stiffness to the entire structure. 8 Two hundred XOUs are arranged in eight rings and eight petals to fill the available geometric area of the telescope and to re-establish the cylindrical symmetry of the nested Wolter I optical design. The current XOU configuration, reported in Fig.…”

Section: Current Ixo X-ray Telescope Design Based On Slumped Platesmentioning

confidence: 99%

“…6,7 The assembling of such telescopes will be based on a principle of hierarchical integration: single mirrors segments will be integrated into elemental modules, usually called an x-ray optical unit (XOU), then assembled and aligned in the flight mirror assembly (FMA) through intermediate azimuthal structures to reestablish the cylindrical symmetry of the nested telescope with a Wolter I (or a Wolter I approximation) optical design. 8 Slumping technology has already been successfully employed for the production of the NuSTAR telescope, launched in 2012, 9,10 which is able to deliver high image quality at a focus of 45 arcsec HEW. 11 Additional studies are currently ongoing both by American and European research groups to further expand the technology in terms of the achievable optical quality (the goal being 5 arcsec HEW).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the surface strength of glass plates shaped by hot slumping process

et al. 2014

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Abstract. Hot slumping technology is under development by several research groups in the world for the realization of grazing-incidence segmented mirrors for x-ray astronomy, based on thin glass plates shaped over a mold at temperatures above the transformation point. The performed thermal cycle and related operations might have effects on the strength of the glass, with consequences for the structural design of the elemental optical modules and, consequently, on the entire x-ray optic for large astronomical missions such as IXO and ATHENA. The mechanical strength of glass plates after they underwent the slumping process was tested through destructive double-ring tests in the context of a study performed by the Astronomical Observatory of Brera with the collaboration of Stazione Sperimentale del Vetro and BCV Progetti. The entire study was done on more than 200 D263 Schott borosilicate glass specimens of dimensions 100 mm × 100 mm and a thickness 0.4 mm, either flat or bent at a radius of curvature of 1000 mm through the pressure-assisted hot slumping process developed by INAF-OAB. The collected experimental data have been compared with nonlinear finite element model analyses and treated with the Weibull statistic to assess the current IXO glass x-ray telescope design, in terms of survival probability, when subjected to static and acoustic loads characteristic of the launch phase. The paper describes the activities performed and presents the obtained results. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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“…Such telescopes assembling will be based on a principle of hierarchical integration: single mirrors segments will be integrated into elemental modules, usually called X-ray Optical Unit (XOU), then assembled and aligned in the Flight Mirror Assembly (FMA) through intermediate azimuthal structures to reestablish the cylindrical symmetry of the nested telescope with Wolter I (or a Wolter I approximation) optical design [8]. The slumping technology has already been successfully employed for the production of NuSTAR telescope, launched in 2012 [9], [10], able to deliver an image quality at focus of 45 arcsec HEW [11].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the surface strength of glass plates shaped by hot slumping process

et al. 2013

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Abstract:The Hot Slumping Technology is under development by several research groups in the world for the realization of grazing-incidence segmented mirrors for X-ray astronomy, based on thin glass plates shaped over a mould at temperatures above the transformation point. The performed thermal cycle and related operations might have effects on the strength characteristics of the glass, with consequences on the structural design of the elemental optical modules and consecutively on the entire X-ray optic for large astronomical missions like for example IXO and ATHENA. The mechanical strength of glass plates after they underwent the slumping process was tested through destructive double-ring tests in the Weibull statistic to assess the current IXO glass X-ray telescope design, in terms of survival probability, when subject to static and acoustic loads characteristic of the launch phase. The paper describes the activities performed and presents the obtained results.

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IXO x-ray mirrors based on slumped glass segments with reinforcing ribs: optical and mechanical design, image error budget, and optics unit integration process

Cited by 12 publications

References 3 publications

X-ray optical units made of glass: achievements and perspectives

X-ray optical units made of glass: achievements and perspectives

Evaluation of the surface strength of glass plates shaped by hot slumping process

Evaluation of the surface strength of glass plates shaped by hot slumping process

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