NIST, X-Ray Optical Systems, University at Albany Win R&D Award for Neutron Focusing Lens

Research and Development Magazine is recognizing a neutron focusing lens developed by X-Ray Optical Systems Inc., the Commerce Department's National Institute of Standards and Technology, and the University at Albany as "one of the 100 most technologically significant new products of the year."

X-Ray Optical Systems of Albany, N.Y., received funding from the NIST-managed Advanced Technology Program to develop the neutron focusing lens. The company also worked with researchers at the NIST Cold Neutron Research Facility and the University at Albany to characterize and improve the lens.

The lens dramatically improves two analytical techniques—neutron depth profiling and prompt gamma activation analysis—which use neutrons to measure the distribution of elements in various materials. For example, prompt gamma activation analysis is used by researchers at NIST to measure accurately the concentration of hydrogen in broken jet engine turbine blades. Hydrogen is known to embrittle metals and has been suspected as the reason for their failure.

In the future, similar lenses will be applied to X-ray focusing, other neutron-based research methods, and medical diagnostic and therapeutic treatments.

NIST research scientists H. Heather Chen-Mayer, David F.R. Mildner and Greg Downing collaborated with Qi-Fan Xiao and Vasily Sharov of X-Ray Optical Systems and University at Albany scientists Walter Gibson and Carolyn MacDonald on development of the lens.

The lens is made of 1,763 glass capillary fibers. These thin hollow hexagonal fibers each contain 1,657 capillary channels that each measure 9 micrometers in diameter (about one-tenth the diameter of a human hair). The lens, therefore, contains 2.9 million tiny channels for directing and focusing neutrons to a 0.5 millimeter spot. The fibers are threaded through four meshes with a concentric pattern of holes. The fibers are parallel at the entrance of the lens but are gradually bent toward the narrow focal point.

In this configuration, the fibers focus a beam of low energy neutrons to a spot less than 1 millimeter in diameter. By scanning a sample across the beam, the focused neutrons can probe a specified area of its surface. Using the lens, the researchers have shown that the sensitivity has increased 60 times for certain submillimeter particles. This improves the limit of detection by a factor of 20 compared to conventional neutron testing methods. Such analytical methods are of great value to the semiconductor industry for analysis of critical materials such as diamond substrates.

Including this year's award, NIST researchers have won 77 R&D; 100 awards since 1973. A 1991 study by the NIST Visiting Committee, an advisory body composed of science and engineering experts from industry and academia, found that more than half of the award- winning entries were either adopted by private firms or translated into NIST-offered measurement services used by U.S. industry.

Research and Development Magazine has annually honored inventors and scientists around the world since 1963 by selecting the 100 most technologically significant new products and processes. Winners are chosen by the magazine editors and a panel of more than 75 scientific experts in a variety of disciplines.

A non-regulatory agency of the Commerce Department's Technology Administration, NIST promotes U.S. economic growth by working with industry to develop and apply technology, measurements and standards.