Story tips from the Department of Energy's Oak Ridge National Laboratory, July 2004

07/15/04

To arrange for an interview with a researcher, please contact the Communications and Community Outreach staff member identified at the end of each tip.

MATERIALS -- Power to Saturn . . .

This month's arrival at Saturn of the Cassini-Huygens spacecraft following a seven-year voyage was made possible partly by work done at Oak Ridge National Laboratory. The spacecraft's instruments are powered by generators that convert heat from plutonium-238 fuel into electricity. ORNL developed and fabricated the protective cladding, iridium alloy clad vent sets, to encapsulate the fuel. The iridium alloy "clad vent sets" are resistant to heat and impact and are designed and tested to remain intact even during an unplanned reentry during the spacecraft's 1997 launch or subsequent gravitational-assist flybys -- a safety feature required by the project. NASA remains an ORNL customer: The iridium alloy-clad vent sets have been used in other deep-space missions (such as Voyager, Galileo and Ulysses) and will be present on the future NASA missions, including the Pluto New Horizons mission planned to explore Pluto and the Kuiper Belt. [Contact: Bill Cabage, 865-574-4399; cabagewh@ornl.gov]

PHYSICS -- Old in the tooth . . .

Methods routinely used by Oak Ridge National Laboratory health physicists to do radiation measurements are helping University of Tennessee researchers determine the age of anthropological finds. A Dosimetry Applications Research Calibration Laboratory team is using radiation testing equipment to date finds such as a bovid (horse or cow) tooth found near an ancient human tooth on the island of Java, Indonesia. By testing the bovid tooth, researchers can determine the age of the rare human tooth while still preserving it. They conservatively estimate the tooth is 500,000 years old. The ORNL team dates sample components such as quartz, feldspar or tooth enamel by doing radiation damage dating. First, scientists determine the dose of the sample by measuring electrons that have been promoted by natural radiation in the surrounding soil into "traps" in the tooth. Next, the dose rate of the contextual material is determined using a gamma spectrometer. By dividing the dose by the dose rate, researchers can determine the relative age of the fossil. Radiation damage dating enables researchers to solve some the greatest mysteries about the history of humankind. [Contact: Bill Cabage 865-574-4399; cabagewh@ornl.gov]

CHEMISTRY -- Photons on missions . . .

Semiconducting polymers that emit light of different colors for hours instead of minutes could have a bright future in the world of cryptography. What makes this possible is a technique developed by Mike Barnes of the lab's Chemical Sciences Division that produces uniformly oriented single polymer molecules in the (non-intuitive) z direction "like nanoscopic antennas," Barnes said. These oriented nanostructures have fluorescence properties that are profoundly different than those of similar molecules isolated in conventional film processing techniques. One newly discovered property, which will be reported in an upcoming issue of Applied Physics Letters, is that these oriented polymer nanostructures are very efficient at emitting single photons. This property could be useful in photonic quantum information processing applications. [Contact: Ron Walli 865-576-0226; wallira@ornl.gov]

Source: Eurekalert & others

Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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