Powell, Cecil Frank, 1903–69, British nuclear physicist, Ph.D. Cambridge, 1927. Powell joined the faculty at the Univ. of Bristol in 1927, was named Melville Wills Professor of Physics in 1948, and was appointed director of the Wills Physical Laboratory there in 1964. He was awarded the 1950 Nobel Prize in Physics for pioneering the study of nuclear particles using photographic emulsions. He used the technique to discover, in 1947, the pi-meson, or pion, a heavy subatomic particle, in the plates of cosmic rays. Powell's discovery helped to establish an orderly view of nuclear processes.