In 1980 he became Professor of Physics at the University of Arkansas; From 1986 to 1994 he was at the Los Alamos National Laboratory, where he became a fellow of the laboratory from 1994 onwards.
1980 wurde er Professor für Physik an der University of Arkansas; von 1986 bis 1994 war er am Los Alamos National Laboratory, wo er ab 1994 Fellow des Labors wurde.