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Speegle, Chet

Publications and source records attributed to Speegle, Chet.

9 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2010

Computer-Controlled Cylindrical Polishing Process for Development of Grazing Incidence Optics for Hard X-Ray Region

The presentation includes grazing incidence X-ray optics, motivation and challenges, mid spatial frequency generation in cylindrical polishing, design considerations for polishing lap, simulation studies and experimental results, future scope, and summary. Topics include current status of replication optics technology, cylindrical polishing process using large size polishing lap, non-conformance of polishin lap to the optics, development of software and polishing machine, deterministic prediction of polishing, polishing experiment under optimum conditions, and polishing experiment based on known error profile. Future plans include determination of non-uniformity in the polishing lap compliance, development of a polishing sequence based on a known error profile of the specimen, software for generating a mandrel polishing sequence, design an development of a flexible polishing lap, and computer controlled localized polishing process.

Khan, Gufran Sayeed↗
NASA NTRS2010

Computer-Controlled Cylindrical Polishing Process for Large X-Ray Mirror Mandrels

We are developing high-energy grazing incidence shell optics for hard-x-ray telescopes. The resolution of a mirror shells depends on the quality of cylindrical mandrel from which they are being replicated. Mid-spatial-frequency axial figure error is a dominant contributor in the error budget of the mandrel. This paper presents our efforts to develop a deterministic cylindrical polishing process in order to keep the mid-spatial-frequency axial figure errors to a minimum. Simulation software is developed to model the residual surface figure errors of a mandrel due to the polishing process parameters and the tools used, as well as to compute the optical performance of the optics. The study carried out using the developed software was focused on establishing a relationship between the polishing process parameters and the mid-spatial-frequency error generation. The process parameters modeled are the speeds of the lap and the mandrel, the tool s influence function, the contour path (dwell) of the tools, their shape and the distribution of the tools on the polishing lap. Using the inputs from the mathematical model, a mandrel having conical approximated Wolter-1 geometry, has been polished on a newly developed computer-controlled cylindrical polishing machine. The preliminary results of a series of polishing experiments demonstrate a qualitative agreement with the developed model. We report our first experimental results and discuss plans for further improvements in the polishing process. The ability to simulate the polishing process is critical to optimize the polishing process, improve the mandrel quality and significantly reduce the cost of mandrel production

Khan, Gufran S.↗
NASA NTRS2010

Design Considerations of Polishing Lap for Computer-Controlled Cylindrical Polishing Process

The future X-ray observatory missions, such as International X-ray Observatory, require grazing incidence replicated optics of extremely large collecting area (3 m2) in combination with angular resolution of less than 5 arcsec half-power diameter. The resolution of a mirror shell depends ultimately on the quality of the cylindrical mandrels from which they are being replicated. Mid-spatial-frequency axial figure error is a dominant contributor in the error budget of the mandrel. This paper presents our efforts to develop a deterministic cylindrical polishing process in order to keep the mid-spatial-frequency axial figure errors to a minimum. Simulation studies have been performed to optimize the operational parameters as well as the polishing lap configuration. Furthermore, depending upon the surface error profile, a model for localized polishing based on dwell time approach is developed. Using the inputs from the mathematical model, a mandrel, having conical approximated Wolter-1 geometry, has been polished on a newly developed computer-controlled cylindrical polishing machine. We report our first experimental results and discuss plans for further improvements in the polishing process.

Khan, Gufran S.↗
NASA NTRS2006

Status of MSFC X-ray Shell Optics Fabrication Capability

We present details of an MSFC development program of electroformed-nickel replicated grazing incidence optics for x-ray imaging. To date a wide variety of mirrors has been produced with diameters ranging from 2.5 cm, for small animal imaging, up to 112 meter, for x-ray astronomy. Around 100 intermediate size shells are currently aboard the HERO x-ray astronomy balloon payload awaiting launch in Fort Sumner, New mexico. Details of the program are presented together with developments currently underway to improve mirror-shell quality from the current approx. 15 arcsec resolution to below 10 arcsec for future x-ray astronomy missions.

Sthal, H. Philip↗
NASA NTRS2004

AS04-AS02-133 Electroformed-Nickel Hard-X-Ray Optic Development at NASA/MSFC

We are developing the nickel electroforming process to fabricate high-quality mirrors for the region. Two applications for these optics are a balloon-borne payload, termed HERO, and a hard-X-ray telescope module for consideration for the Constellation-X mission. In the formation on shells, of 15 arcsec angular resolution, will provide over 200 sq cm of effective collecting area unprecedented sensitivity in the 20-75 keV region. A first flight of a partial payload, feature approximately 1/4 of the total collecting area, is scheduled for the Spring of 2004. In the Co-application, two mirror shells, of diameters 150 and 230 mm, are being fabricated. This is particularly challenging as high angular resolution must be maintained with shells of only 1 mm thickness (driven by the tight weight budget for the mission). Further, the shells must be low (less than 5 A on sub-micron spatial scales) to permit efficient use of planned multilayer coatings which must release cleanly from their forming mandrels without any surface degradation.

Ramsey, Brian↗
NASA NTRS2003

Figure Measurements of High-Energy-X-Ray Replicated Optics

We are developing grazing incidence x-ray optics for a balloon-borne hard-x-ray telescope (HERO). The HERO mirror shells are fabricated using electroform-nickel replication off super-polished cylindrical mandrels. One of the sources for mirror resolution error is departure of the shell figure from prescription. We have modified a Vertical-scan Long Trace Profilometer (VLTP) in order to measure the figure of the inner surface of the HERO mirror shells for diameters as small as 76 mm. Mirror alignment method and sources for systematic errors will be discussed. Comparison of figure metrology of the mandrel and the shells will be presented together with results from x-ray tests.

Gubarev, Mikhail↗
NASA NTRS2003

AM03-AM121-115 Hard X-Ray Optics Development at MSFC

We have developed the electroformed-nickel replication process to enable us to fabricate light-weight hard-x-ray region. Two projects currently utilizing this technology are the production of over 250 r from 5 to 10 cm, for our HERO balloon payload, and 15- and 23-cm-diameter shells for a prototype module. The challenge for the former is to fabricate, mount, align and fly a large number of high-r constraints of a modest budget. For the latter, the challenge is to maintain high angular resolution shell thicknesses (100 micron) which make the shells extremely sensitive to electroforming stresses process does not degrade the ultra-smooth surface finish (approx. 3 A required for eventual multilayer c on these two programs.

Ramsey, Brian↗
NASA NTRS2001

Electrodeposition of Low Stress Nickel Phosphorous Alloys for Precision Component Fabrication

Nickel alloys are favored for electroforming precision components. Nickel phosphorous and nickel cobalt phosphorous are studied in this work. A completely new and innovative electrolytic process eliminates the fumes present in electroless processes and is suitable for electroforming nickel phosphorous and nickel cobalt phosphorous alloys to any desirable thickness, using soluble anodes, without stripping of tanks. Solutions show excellent performance for extended throughput. Properties include, cleaner low temperature operation (40 - 45 C), high Faradaic efficiency, low stress, Rockwell C 52 - 54 hardness and as much as 2000 N per square millimeter tensile strength. Performance is compared to nickel and nickel cobalt electroforming.

Engelhaupt, Darell↗