Design and fabrication of refractive nulls for testing the segmented mirrors of the Constellation-X spectroscopy x-ray telescope (SXT)

Lehan, John P.; Hadjimichael, Theo; Zhang, W. W.

doi:10.1117/12.615316

Cited by 6 publications

(6 citation statements)

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“…For highly aspherical x-ray optics designed for two-dimensional (2D) manipulation of x-rays, such as paraboloidal mirror shells for space x-ray telescopes [26,27] or diaboloidal mirrors [28,29] for beamline applications at x-ray facilities, the sagittal and tangential curvatures of the optical surfaces can differ by a few orders of magnitude with significant variation along the mirror. Surface characterization of such aspherical optics can be performed with Fizeau interferometry in the CWI mode [7,9,30] or with specially developed refractive nulls [24,25], but systematic errors such as retrace error are potentially even more significant. The retrace error in a particular measurement depends on the shape, tilt, and focus (lateral position) of the SUT (see, for example, Ref.…”

Section: Retrace Errorsmentioning

confidence: 99%

Binary pseudo-random array (BPRA) for inspection and calibration for cylindrical wavefront interferometry

Munechika,

Rochester,

Chao

et al. 2023

Astronomical Optics: Design, Manufacture, and Test of Space and Ground Systems IV

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High-accuracy metrology is vitally important in manufacturing ultra-high-quality free-form mirrors designed to manipulate X-ray light with nanometer-scale wavelengths. However, surface topography measurements are instrument dependent, and without the knowledge of how the instrument performs under the practical usage conditions, the measured data contain some degree of uncertainty. Binary Pseudo Random Array (BPRA) “white noise” artifact are effective and useful for characterizing the Instrument Transfer Function (ITF) of surface topography metrology tools and wavefront measurement instrument. BPRA artifact contains features with all spatial frequencies in the instrument bandpass with equal weight. As a result, power spectral density of the patterns has a deterministic white-noise-like character that allows direct determination of the ITF with uniform sensitivity over the entire spatial frequency range. The application examples include electron microscopes, x-ray microscopes, interferometric microscopes, and large field-of-view Fizeau Interferometers. Furthermore, we will introduce the application of BPRA method to characterizing the ITF of Cylindrical Wavefront Interferometry (CWI), by developing the BPRA artifact which matches the radius of curvature of the cylindrical wavefront. The data acquisition and analysis procedures for different applications of the ITF calibration technique developed are also discussed.

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Section: Retrace Errorsmentioning

confidence: 99%

Binary pseudo-random array (BPRA) for inspection and calibration for cylindrical wavefront interferometry

Munechika,

Rochester,

Chao

et al. 2023

Astronomical Optics: Design, Manufacture, and Test of Space and Ground Systems IV

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“…5 In this case, some axial curvature is desired, because the mirrors themselves have axial curvature by design ͑a radius of about a kilometer͒, which improves the telescope imaging performance. 6 Because we were interested in measuring the net axial curvature as a check on our singlet metrology, our mirror was about 1/50 wave RMS and almost free of second-order error.…”

Section: Discussionmentioning

confidence: 99%

Simple method of aligning cylindrical air-spaced elements

Lehan

Hadjimichael

2007

Opt. Eng

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“…It copies the figure of conventionally fabricated mandrels to cOlllIJlercially procured (Schott D263) thin (-0.4 mm) float glass sheets while preserving their excellent micro-roughness (-4A rms measured over a 300 /lm span). As shown in Figure 2 (right panel), it has been able to make mirror substrates consistently at -6.5 are-seconds (HPD); Each entry in the histogram represents a substrate pair which has been precisely measured with optical metrology [19,20,21,22,23,24] and whose x-ray imaging performance calculated with standard performance prediction techniques. The glass slumping process is capable of making substrates the meet the requirements of a sub-l0 arc-second mirror assembly: It has been used to making the more than 10,000 substrates for the NuST AR mission [7].…”

Section: Technical Approaches and Statusmentioning

confidence: 99%

Next generation astronomical x-ray optics: high angular resolution, light weight, and low production cost

et al. 2012

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X-ray astronomy depends on the availability of telescopes with high resolution and large photon collecting areas. Since x-ray observation can only be carried out above the atmosphere, these telescopes must be necessarily lightweight. Compounding the lightweight requirement is that an x-ray telescope consists of many nested concentric shells, which further require that x-ray mirrors must also be geometrically thin to achieve high packing efficiency. This double lightweight and geometrically thin requirement poses significant technical challenges in fabricating the mirrors and in integrating them into mirror assemblies. This paper reports on the approach, strategy and status of our x-ray optics development program whose objective is to meet these technical challenges at modest cost to enable future x -ray missions, including small Explorer missions in the near term, probe class missions in the medium term, and large flagship missions in the long term.

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Design and fabrication of refractive nulls for testing the segmented mirrors of the Constellation-X spectroscopy x-ray telescope (SXT)

Cited by 6 publications

References 0 publications

Binary pseudo-random array (BPRA) for inspection and calibration for cylindrical wavefront interferometry

Binary pseudo-random array (BPRA) for inspection and calibration for cylindrical wavefront interferometry

Simple method of aligning cylindrical air-spaced elements

Next generation astronomical x-ray optics: high angular resolution, light weight, and low production cost

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