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Proceedings Paper

New fabrication methodology for fine-feature high-aspect-ratio structures made from high-Z materials
Author(s): Upendra D. Desai; Larry E. Orwig; David Clark; Michael Appleby
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Paper Abstract

Radiological imagin relies heavily on collimators to achieve diagnostic x-ray images. These collimating structures are required due to the lack of efficient x-ray reflectors or refractors needed to make lenses or mirrors. In order to achieve higher resolution x-ray images, finer collimator geometries are needed. The two critical parameters that define the fineness of a collimator are the length of the collimator structure and the aperture size. Current collimator fabrication technology provides structures with coarse cell sizes, which require long structural lengths, to achieve image optimization. Finer collimator geometries would help reduce the overall length of collimating structures. Tecomet, of Woburn, MA has developed a new technology to fabricate fine-featured, high aspect ratio structures made from high Z materials. These collimating structures have been made from tungsten with aspect ratios above 50:1 and geometry features less than 20 microns. This technology has enabled advancements in the design of x-ray coded apertures. This has opened the door to new ideas for x-ray imaging. Optimization coders, made from tungsten, can now be designed and fabricated to achieve very high angular resolution. Significant reduction in weight is realized due to the reduction in collimator thickness. The collimators made using these fabrication methods also provide greater long-term structural stability compared to collimators used in diagnostic x-ray imaging using lead.

Paper Details

Date Published: 30 August 1999
PDF: 9 pages
Proc. SPIE 3874, Micromachining and Microfabrication Process Technology V, (30 August 1999); doi: 10.1117/12.361236
Show Author Affiliations
Upendra D. Desai, NASA Goddard Space Flight Ctr. (United States)
Larry E. Orwig, NASA Goddard Space Flight Ctr. (United States)
David Clark, NASA Goddard Space Flight Ctr. (United States)
Michael Appleby, Thermo Electron\Tecomet (United States)

Published in SPIE Proceedings Vol. 3874:
Micromachining and Microfabrication Process Technology V
James H. Smith; Jean Michel Karam, Editor(s)

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