March 28, 2000

Brookhaven Lab Scientist Wins American Chemical Society Award

UPTON, NY - The American Chemical Society (ACS) has named Richard L. Hahn, a senior scientist at the U.S. Department of Energy's Brookhaven National Laboratory, the winner of the 2000 ACS Nuclear Chemistry Award. He will receive a citation certificate and a $3,000 award during a March 28 ceremony at the ACS meeting being held this week in San Francisco. The Nuclear Chemistry Award was established in 1955 and is given annually by the ACS to recognize outstanding scientific achievement in the field.

Hahn's citation is for "His leadership role in experiments for the detection and measurement of solar neutrinos, for wide-ranging investigations of chemical and nuclear properties of the heaviest elements, and for numerous nuclear reaction and spectroscopy studies."

Hahn is the fifth Brookhaven scientist to win the award. Prior to Hahn, the most recent Brookhaven awardee was Raymond Davis, in 1979, for his work with solar neutrinos.

"I am very pleased that the members of the ACS award selection committee, my peers in the nuclear chemistry community, thought my research accomplishments were worthy of this honor, especially my studies at Brookhaven during the past 13 years," said Hahn. "Basic research in solar neutrinos is on the cutting edge of science, bringing together people from a variety of fields, physicists and chemists, experimenters and theorists, to determine if our present theories have to be recast to explain all the observed properties of neutrinos."

A respected chemist at Brookhaven, Hahn has spent years at the forefront of solar neutrino research, participating in experiments around the world. In 1987, he led the U.S. team in the international collaboration that built and operated the GALLEX solar-neutrino experiment in the underground Gran Sasso National Laboratory in Italy. This experiment, which uses 30 tons of gallium as the neutrino detector, was born out of research done at Brookhaven in the 1970s.

Neutrinos are routinely produced in the sun as by-products of the nuclear fusion reactions that produce the sun's energy. GALLEX measures the number of these low-energy solar neutrinos, with important implications for nuclear physics, astrophysics and particle physics. Each month, neutrino collisions produce 5 to 15 atoms of germanium among the experiment's 260,000 trillion trillion gallium atoms. Hahn and his group were responsible for separating, purifying and collecting these germanium atoms with absolute accuracy. Hahn also played a central role in analyzing and publishing the GALLEX results.

Data from GALLEX, and from four other solar neutrino detectors around the world, appear to support the hypothesis that solar neutrinos are transformed into the other known neutrino types, or "flavors," as they travel to Earth. Such "neutrino flavor oscillations" would require the neutrinos to have mass. If true, the discovery would overturn the neutrino's very definition, force reevaluation of fundamental theories, and perhaps even help solve the missing-matter problem in the universe.

Currently, Hahn and his group are responsible for several key chemical aspects of the newest neutrino detector, the Sudbury Neutrino Observatory, or SNO, located 6,800 feet below ground in a nickel mine in Ontario, Canada. Hahn's expertise is crucial in reducing naturally-occurring radioactive contaminants to the extremely low levels required to allow the experiment to detect solar neutrinos. SNO, which began collecting data in October 1999, is unique in that it is the only neutrino experiment that can detect the three known neutrino flavors. Observation of the products of these neutrino oscillations would constitute a "smoking gun" for the existence of neutrino mass.

Prior to studying neutrinos, Hahn did basic research on the properties and nuclear reaction mechanisms of the heaviest chemical elements, the "man-made" elements that lie above uranium in the periodic table. He is also the co-discoverer of 23 radioactive isotopes.

Born and raised in New York City, Hahn first came to Brookhaven as a research associate while completing his 1960 Ph.D. in nuclear chemistry from Columbia University, following his 1956 M.A. from Columbia and 1955 B.S. from Brooklyn College. He then spent 25 years at Oak Ridge National Laboratory, including 10 as director of the transuranium research laboratory there. He returned to Brookhaven's Chemistry Department as a chemist in 1986, was tenured in 1987, and was named senior chemist in 1994.

Along with the ACS award, his honors have included the 1977 Radiation Industry Award of the American Nuclear Society for charged particle activation analysis research, and the BNL Distinguished Research and Development Award in 1997. He has been elected to several offices of the ACS's Division of Nuclear Chemistry and Technology, including chair in 1982, and has been vice-chair and chair of the National Research Council's Committee on Nuclear and Radiochemistry.

The U.S. Department of Energy's Brookhaven National Laboratory creates and operates major facilities available to university, industrial and government personnel for basic and applied research in the physical, biomedical and environmental sciences, and in selected energy technologies. The Laboratory is operated by Brookhaven Science Associates, a not-for -profit research management company, under contract with the U.S. Department of Energy.

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NOTE TO LOCAL EDITORS: Richard L. Hahn is a resident of Moriches, NY.




Last updated 5/28/99 by Public Affairs