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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Ray-trace analysis of glancing-incidence X-ray optical systems

The results of a ray-trace analysis of several glancing-incidence X-ray optical systems are presented. The object of the study was threefold. First, the vignetting characteristics of the S-056 X-ray telescope were calculated using experimental data to determine mirror reflectivities. Second, a small Wolter Type I X-ray telescope intended for possible use in the Geostationary Operational Environmental Satellite program was designed and ray traced. Finally, a ray-trace program was developed for a Wolter-Schwarzschild X-ray telescope.

Foreman, J. W., Jr.↗
NASA NTRS1978

A coordinated X-ray, optical, and microwave study of the flare star Proxima Centauri

Results are reported for a three-day coordinated observing program to monitor the flare star Proxima Centauri in the X-ray, optical, and radio spectrum. During this interval 30 optical flares and 12 possible radio bursts were observed. The SAS 3 X-ray satellite made no X-ray detections. An upper limit of 0.08 on the X-ray/optical luminosity ratio is derived for the brightest optical flare. The most sensitive of the radio telescopes failed to detect 6-cm emission during one major and three minor optical flares, and on this basis an upper limit on the flare radio emission (1 hundred-thousandth of the optimal luminosity) is derived.

Haisch, B. M.↗
NASA NTRS1995

Development of microchannel plate x-ray optics

The goal of this research program was to develop a novel technique for focusing x-rays based on the optical system of a lobster's eye. A lobster eye employs many closely packed reflecting surfaces arranged within a spherical or cylindrical shell. These optics have two unique properties: they have unlimited fields of view and can be manufactured via replication of identical structures. Because the angular resolution is given by the ratio of the size of the individual optical elements to the focal length, optical elements with size on the order of one hundred microns are required to achieve good angular resolution with a compact telescope. We employed anisotropic etching of single crystal silicon wafers for the fabrication of micron-scale optical elements. This technique, commonly referred to as silicon micromachining, is based on silicon fabrication techniques developed by the microelectronics industry. We have succeeded in producing silicon lenses with a geometry suitable for a 1-d focusing x-ray optics. These lenses have an aspect ratio (40:1) suitable for x-ray reflection and have very good optical surface alignment. We have developed a number of process refinements which improved the quality of the lens geometry and the repeatability of the etch process. In addition to the silicon fabrication, an x-ray beam line was constructed at Columbia for testing the optics. Most recently, we have done several experiments to find the fundamental limits that the anisotropic etch process placed on the etched surface roughness.

Kaaret, Philip↗
NASA NTRS2010

The X-Ray Optics for the High Angular Resolution Imager (HARI)

This slide presentation shows the basic parameters of the x-ray optics, the housing,a graph of the effective area vs energy, another graph showing the angular off-set vs HEW, and a series of graphs showing the detector offsets and tilts,

Weisskopf, M. C.↗
NASA NTRS2015

X-Ray Optics at NASA Marshall Space Flight Center

NASA's Marshall Space Flight Center (MSFC) engages in research, development, design, fabrication, coating, assembly, and testing of grazing-incidence optics (primarily) for x-ray telescope systems. Over the past two decades, MSFC has refined processes for electroformed-nickel replication of grazing-incidence optics, in order to produce high-strength, thin-walled, full-cylinder x-ray mirrors. In recent years, MSFC has used this technology to fabricate numerous x-ray mirror assemblies for several flight (balloon, rocket, and satellite) programs. Additionally, MSFC has demonstrated the suitability of this technology for ground-based laboratory applications-namely, x-ray microscopes and cold-neutron microscopes and concentrators. This mature technology enables the production, at moderately low cost, of reasonably lightweight x-ray telescopes with good (15-30 arcsecond) angular resolution. However, achieving arcsecond imaging for a lightweight x-ray telescope likely requires development of other technologies. Accordingly, MSFC is conducting a multi-faceted research program toward enabling cost-effective production of lightweight high-resolution x-ray mirror assemblies. Relevant research topics currently under investigation include differential deposition for post-fabrication figure correction, in-situ monitoring and control of coating stress, and direct fabrication of thin-walled full-cylinder grazing-incidence mirrors.

X-ray Optics↗
NASA NTRS2015

X-Ray Optics at NASA Marshall Space Flight Center

NASA's Marshall Space Flight Center (MSFC) engages in research, development, design, fabrication, coating, assembly, and testing of grazing-incidence optics (primarily) for x-ray telescope systems. Over the past two decades, MSFC has refined processes for electroformed-nickel replication of grazing-incidence optics, in order to produce high-strength, thin-walled, full-cylinder x-ray mirrors. In recent years, MSFC has used this technology to fabricate numerous x-ray mirror assemblies for several flight (balloon, rocket, and satellite) programs. Additionally, MSFC has demonstrated the suitability of this technology for ground-based laboratory applications-namely, x-ray microscopes and cold-neutron microscopes and concentrators. This mature technology enables the production, at moderately low cost, of reasonably lightweight x-ray telescopes with good (15-30 arcsecond) angular resolution. However, achieving arcsecond imaging for a lightweight x-ray telescope likely requires development of other technologies. Accordingly, MSFC is conducting a multi-faceted research program toward enabling cost-effective production of lightweight high-resolution x-ray mirror assemblies. Relevant research topics currently under investigation include differential deposition for post-fabrication figure correction, in-situ monitoring and control of coating stress, and direct fabrication of thin-walled full-cylinder grazing-incidence mirrors.

X-ray telescope↗
NASA NTRS2009

An Investigation of Differential Deposition for Figure Corrections in Full-Shell Grazing-Incidents X-Ray Optics

We are investigating differential deposition as a way of correcting small figure errors inside full-shell grazing-incidence x-ray optics. The optics in our study are fabricated using the electroformed-nickel-replication technique, and the figure errors arise from fabrication errors in the mandrel, from which the shells are replicated, as well as errors induced during the electroforming process. Combined, these give sub-micron-scale figure deviations which limit the angular resolution of the optics to approx. 10 arcsec. Sub-micron figure errors can be corrected by selectively depositing (physical vapor deposition) material inside the shell. The requirements for this filler material are that it must not degrade the ultra-smooth surface finish necessary for efficient x-ray reflection (approx. 5 A rms), and must not be highly stressed. In addition, a technique must be found to produce well controlled and defined beams within highly constrained geometries, as some of our mirror shells are less than 3 cm in diameter.

Gubarev, Mikhail V.↗
NASA NTRS2014

Analysis of Active Figure Control Effects on Mounting Strategy for X-Ray Optics

As part of ongoing development efforts at MSFC, we have begun to investigate mounting strategies for highly nested x-ray optics in both full-shell and segmented configurations. The analytical infrastructure for this effort also lends itself to investigation of active strategies. We expect that a consequence of active figure control on relatively thin substrates is that errors are propagated to the edges, where they might affect the effective precision of the mounting points. Based upon modeling, we describe parametrically, the conditions under which active mounts are preferred over fixed ones, and the effect of active figure corrections on the required number, locations, and kinematic characteristics of mounting points.

Kolodziejczak, Jeffrey J.↗
NASA NTRS2010

Concerning the Development of the Wide-Field Optics for WFXT Including Methods of Optimizing X-Ray Optical Prescriptions for Wide-Field Applications

We present a progress report on the various endeavors we are undertaking at MSFC in support of the Wide Field X-Ray Telescope development. In particular we discuss assembly and alignment techniques, in-situ polishing corrections, and the results of our efforts to optimize mirror prescriptions including polynomial coefficients, relative shell displacements, detector placements and tilts. This optimization does not require a blind search through the multi-dimensional parameter space. Under the assumption that the parameters are small enough so that second order expansions are valid, we show that the performance at the detector can be expressed as a quadratic function with numerical coefficients derived from a ray trace through the underlying Wolter I optic. The optimal values for the parameters are found by solving the linear system of equations creating by setting derivatives of this function with respect to each parameter to zero.

Weisskopf, M. C.↗
NASA NTRS1997

Ion Figuring of Replicated X-Ray Optics

This investigation included experiments to demonstrate ion beam figuring effects on electroless nickel with the expressed desire to figure X-ray optic mandrels. It was important to establish that ion beam figuring did not induce any adverse effects to the nickel surface. The ion beam has consistently been shown to be an excellent indicator of the quality of the subsurface. Polishing is not the only cause for failure in the ion beam final figuring process, the material composition is equally important. Only by careful consideration of both these factors can the ion beam final figuring process achieve its greatest potential. The secondary goal was to construct a model for representing the ion beam material removal rate. Representing the ion beam removal rate is only an approximation and has a number of limiting factors. The resolution of the metrology apparatus limits the modeling of the beam function as well. As the surface error corrections demand more precision in the final figuring, the model representing beam function must be equally precise. The precision to which the beam function can be represented is not only determined by the model but also by the measurements producing that model. The method developed for determining the beam function has broad application to any material destined to be ion beam figured.

Cantey, Thomas M.↗
NASA NTRS2000

Astronomical X-Ray Optics

Over the past two decades, grazing incidence optics have transformed observational x-ray astronomy into a major scientific discipline at the cutting edge of research in astrophysics and cosmology. This review summarizes the fundamental design principles of grazing incidence optics for astronomical applications, describes the capabilities of the current generation of x-ray telescopes, and explores several avenues of future development.

Joy, M. K.↗
NASA NTRS1988

X-ray, optical, and IR luminosity correlations in quasars

For a sample of 88 radio-quiet quasars that includes 12 X-ray upper limits, it is found that the X-ray and IR luminosities follow a significantly nonlinear relation that is consistent with that found for the X-ray and optical luminosities. The redshift dependence is weak and may be nonexistent. Since the optical through IR continuum of quasars is much the same shape as a function of luminosity, this implies that the nonlinear relation between the X-ray luminosity and the optical and IR luminosities is due to a systematic change in the X-ray continuum of quasars with increasing luminosity. Either the X-ray continuum must flatten with increasing luminosity, or the overall normalization relative to the optical and IR must decrease. Simple continuum models which link the IR and X-ray portions of the continuum by a single power law arising from the same synchrotron mechanism can be ruled out.

Kriss, Gerard A.↗
NASA NTRS2011

Size Optimization for Mirror Segments for X-Ray Optics

The flight mirror assemblies (FMA) for X-ray telescopes similar to that of the International X-ray Observatory (IXO) concept consist of several thousands of individual mirror segments. The size, shape, and location of these mirrors affect many characteristics of the telescope design. Mission requirements among other factors in turn restrict mirror segment parameters such as thickness, axial- length, azimuthal span, and mass density. This paper provides an overview of the critical relationships relating to mirror segment size and configuration throughout the design and analysis of an X-ray mirror assembly. A computational analysis is presented in the form of ray tracing pairs of thin X-ray mirror segments of varying sizes aligned in gravity and supported using kinematic constraints with corresponding self weight distortions calculated using finite element analysis (FEA). The work in this paper may be used as a starting point for determining mirror segment sizes for X-ray missions like that of IXO and beyond.

Biskach, Michael P.↗
NASA NTRSDate not supplied

Mirror Tech Days (11/02/2021)Next Generation Astronomical X-ray Optics:High Resolution, Light Weight, & Low Cost

We have demonstrated the basic elements of a technology to make high-resolution, light-weight, and low-cost X-ray optics. We continue to advance this technology to meet all requirements of Lynx: performance and programmatic. This technology uses only commercially available equipment and materials. It piggybacks on the semiconductor industry, avoiding obsolescence and ensuring continual advance. This technology can be used for missions of all sizes: sub-orbital, SmallSats, Pioneers, SMEX, MIDEX, Probes, and Flagships(Lynx).

X-Ray↗