&lt;title&gt;Calibration of a vertical-scan long trace profiler at MSFC&lt;/title&gt;

Gubarev, Mikhail V.; Kester, Thomas; Takacs, Peter Z.

doi:10.1117/12.453648

Cited by 12 publications

(5 citation statements)

References 5 publications

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“…In theory only the innermost foil in each batch of forming will have the right radius/grazing angle match, the rest of the stack will have the matching error, from inner to outer foils in a particular batch, which was reduced from 9.2%/2.3% for Suzaku to 2.5%/1.2% for ASTRO-H. Axial figure: generally is improved from 4 Pm to 1-2 Pm, due to the improvement on surface figure error of the substrate forming mandrels. RMS error of the figure slope is about 0.4 arc-minute 3 .…”

Section: Substrate Formingmentioning

confidence: 88%

Calibration of the Soft X-ray Telescopes (SXT) onboard the ASTRO-H satellite

et al. 2013

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ASTRO-H is an astrophysics satellite dedicated for non-dispersive X-ray spectroscopic study on selective celestial X-ray sources. Among the onboard instruments there are four Wolter-I X-ray mirrors of their reflectors' figure in conical approximation. Two of the four are soft X-ray mirrors 1 , of which the energy range is from a few hundred eV to 15 keV. The focal point instruments will be a calorimeter (SXS) and a CCD camera (SXI), respectively. The mirrors were in quadrant configuration with photons being reflected consecutively in the primary and secondary stage before landing on the focal plane of 5.6 m away from the interface between the two stages. The reflectors of the mirror are made of heat-formed aluminum substrate of the thickness gauged of 152 μm, 229 μm, and 305 μm of the alloy 5052 H-19, followed by epoxy replication on gold-sputtered smooth Pyrex cylindrical mandrels to acquire the X-ray reflective surface. The epoxy layer is 10 μm nominal and surface gold layer of 0.2 μm. Improvements on angular response over its predecessors, e.g. Astro-E1/Suzaku mirrors, come from error reduction on the figure, the roundness, and the grazing angle/radius mismatching of the reflecting surface, and tighter specs and mechanical strength on supporting structure to reduce the reflector positioning and the assembly errors.Each soft x-ray telescope (SXT), FM1 or FM2, were integrated from four independent quadrants of mirrors. The stray-light baffles, in quadrant configuration, were mounted onto the integrated mirror. Thermal control units were attached to the perimeter of the integrated mirror to keep the mirror within operating temperature in space. The completed instrument went through a series of optical alignment, thus made the quadrant images confocal and their optical axes in parallel to achieve highest throughput possible. Environmental tests were carried out, and optical quality of the telescopes has been confirmed. The optical and x-ray calibrations also include: angular resolution, effective area in the energy range of ~ 0.4 -12keV, off-axis response, etc. Some of those are being carried out by our counterpart at JAXA/ISAS, Japan. We report the calibration results of the FM1 and FM2 that were obtained at Goddard Space Flight Center.

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Section: Substrate Formingmentioning

confidence: 88%

Calibration of the Soft X-ray Telescopes (SXT) onboard the ASTRO-H satellite

et al. 2013

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“…RMS error of the figure slope is about 0.4 arc-minute 3 Roundness: error of 1/3 arc-minute (substrate size difference ~ +/-1), which translates to 10 μm in reflector edge positioning error in the alignment bar grooves. RMS of this term is on an order of 1 arc-minute, which largely a limiting factor for reaching a sub-arc-minute image quality.…”

Section: Reflectorsmentioning

confidence: 98%

ASTRO-H Soft X-ray Telescope (SXT)

et al. 2011

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ASTRO-H is an astrophysics satellite dedicated for X-ray spectroscopic study non-dispersively and to carry out survey complementally, which will be borne out of US-Japanese collaborative effort. Among the onboard instruments there are four conically approximated Wolter-I X-ray mirrors, among which two of them are soft X-ray mirrors\ of which the energy range is from a few hundred eV to 15 keY, currently being fabricated in the X-ray Optics Lab at Goddard Space Flight Center. The focal point instruments will be a calorimeter (SXS) and a CCD camera (SXI), respectively. The reflectors of the mirror are made of heat-formed aluminum substrate of the thickness gauged of 152 !lm, 229 !lm, and 305 !lm of the alloy 5052 H-19, followed by epoxy replication on gold-sputtered smooth Pyrex cylindrical mandrels to acquire the X-ray reflective surface. The epoxy layer is 10 !lm nominal and surface gold layer of 0.2 !lm. Improvements on angular response over the Astro-ElISuzaku mirrors come from error reduction on the figure, the roundness, and the grazing angle/radius mismatching of the reflecting surface, and tighter specs and mechanical strength on supporting structure to reduce the reflector positioning and the assembly errors. In this paper, we report the results of calibration of the engineering model of SXT (EM), and project the quality of the flight mirrors.Keywords: X-ray Optics, X-ray Telescope, X-ray Astrophysical Instrument IntrodnctionConical approximation ofthe Wolter-I type X-ray imagers has been a major tool for spectroscopic study in the last quarter of century since the launch of a sounding rocket experiment to study SN 1987 A. The high throughput, essential for the spectroscopic study, of the telescope is provided by using thin-foil reflectors, and the continuous improvement of angular response on X-ray imaging is accomplished by switching the substrate surface smoothing scheme from earlier lacquer-dipping to recent epoxy replication that reduced the mid-frequency waviness 2 • The low micro-roughness of the surface produces specular reflection of X-rays, with high Z material such as Au, Pt, or Ir as the reflecting surface. The energy range coverage can be up to 15 ke V by lowering the grazing angle. Despite the continuous improvement over the last two decades from 4 to 1.7 arc-minutes, the demand of even better angular resolution of such thin-foil mirrors is high. The current image quality is still far from achieving the conical approximation limit, which is about 0.2 arc-minute. The difficulty comes from the relatively weak mechanical integrity of the reflectors and the imprecision in the assembly/aligmnent scheme. The improvement ofHPD from the Suzaku mirror of2 arc-minutes to the recent test of engineering model of ASTRO-H of 1 arc-minute will be the main subject of this paper.

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“…The shell profiles were measured in two separate runs (Gubarev et al 2001). The parabolic section was profiled first.…”

Section: Experimental Measurementsmentioning

confidence: 99%

A Hybrid Method for Calculating Residual Stress and Deformation in Space Hardware on Earth

Britz¹,

Gilbert²,

Ooi³

2012

J. Aerosp. Eng.

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Many times in testing space hardware it is desirable to quantify residual von Mises stresses and deformation in a test article which will ultimately be placed in a micro-gravity environment. When testing in a 1-g environment the stresses and deformations include the contributions due to weight. This investigation demonstrates a hybrid method used to identify the residual von Mises and deformations that reflect a no weight condition. To this end, an example of a hard X-ray space mirror is presented to demonstrate this hybrid method which combines finite element analysis with experimental profile measurements, made under gravity loading, on a prototype formed by electroforming a thin shell on a cylindrical aluminum mandrel.

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<title>Calibration of a vertical-scan long trace profiler at MSFC</title>

Cited by 12 publications

References 5 publications

Calibration of the Soft X-ray Telescopes (SXT) onboard the ASTRO-H satellite

Calibration of the Soft X-ray Telescopes (SXT) onboard the ASTRO-H satellite

ASTRO-H Soft X-ray Telescope (SXT)

A Hybrid Method for Calculating Residual Stress and Deformation in Space Hardware on Earth

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