PHILADELPHIA – President George W. Bush announced today that Raymond Davis Jr., research professor of physics at the University of Pennsyl-vania, is among 15 recipients of the 2001 National Medal of Science.

Penn scientists have now received the National Medal of Science two years in a row; chemist Ralph F. Hirschmann was similarly honored in 2000.

Davis conceived, built and ran the first experiment to detect neutrinos from the core of the sun, giving rise to the field of neutrino physics. Using chlorine detectors in the 1960s, he found only one-third the number of neutri-nos predicted by the accepted solar model, a result that has been confirmed by later experiments including the Kamiokande and Sudbury Neutrino Obser-vatory collaborations in which Penn has played a major part.

Davis joined Penn in 1985 after a 37-year career at Brookhaven National Laboratory. He is a member of the National Academy of Sciences and the American Academy of Arts and Sciences.

The National Medal of Science honors pioneering scientific research that has enhanced our basic understanding of life and the world around us. The National Science Foundation administers the award established by Con-gress in 1959. Including this year's laureates, the honor has been conferred on 401 distinguished scientists and engineers, six of them from Penn.