Cecil Frank Powell
Powell, Cecil Frank (1903-1969) was a British physicist who won the 1950 Nobel Prize in physics for developing a simple technique to photograph the action of high-speed subatomic particles and for his discoveries made with the method.
Powell was born on Dec. 5, 1903, in Tonbridge, England. His parents were Elizabeth Caroline (Bisacre) Powell, a schoolteacher's daughter, and Frank Powell, a gunsmith. Powell became interested in physics as a boy and won scholarships to Cambridge University, where he graduated with honors in natural science in 1925. Powell remained at Cambridge for graduate studies under British physicists Charles Thomson Rees Wilson and Ernest Rutherford. Powell used Wilson's cloud chamber in his first major research project, adding to an understanding of how gases condense in the chamber, a device that made the paths of electrically charged subatomic particles visible. This work earned Powell a Ph.D. degree in 1927. The next year, Powell began teaching at the University of Bristol, where he remained until 1969.
Powell became interested in the use of photographic plates to detect the tracks of electrically charged particles. He arranged for two photographic firms to develop special film coatings, and in 1946 he used the new film to study cosmic radiation. In 1947, Powell and his colleagues detected the first known meson when they discovered a pion in a shower of cosmic rays. A meson is a subatomic particle. There are many types of mesons. The pion or pi-meson is the lightest. It has a mass equal to 15 percent of the mass of a proton. The heaviest meson, called an upsilon particle, is about 10 times as heavy as a proton. Powell also discovered the k-meson (also called kaon), and his technique came to be widely used by physicists.
Powell became active in scientific organizations concerned about the spread of nuclear weapons, urging the British government to ban such weapons. He became a founding member in 1955 of the Pugwash Conferences on Science and World Affairs, which unites scientists to work against nuclear war.