On December 5, 1903, English physicist and nobel Laureate Cecil Frank Powell, was born. Powell was awarded the 1950 Nobel Prize in Physics for his development of the photographic method of studying nuclear processes and for the resulting discovery of the pion. The pion proved to be the hypothetical particle proposed in 1935 by Yukawa Hideki of Japan in his theory.
Cecil Frank Powell joined Sidney Sussex College, Cambridge and graduated in 1925 in natural sciences. He then worked at the Cavendish Laboratory, Cambridge, under C.T.R. Wilson and Lord Rutherford, conducting research into condensation phenomena, and gaining his Ph.D. in Physics in 1927. At the University of Bristol, Powell became assistant to A.M. Tyndall in the H.H. Wills Physical Laboratory. He later became lecturer there and in 1948 he was appointed Melville Wills Professor of Physics. At Bristol, Powell devoted his time to the development of techniques for measuring the mobility of positive ions, to establishing the nature of the ions in common gases, and to the construction and use of a Cockcroft generator to study the scattering of atomic nuclei.
Powell further developed methods s employing specialised photographic emulsions to facilitate the recording of the tracks of elementary particles, and in 1938 began applying this technique to the study of cosmic radiation. Powell exposed photographic plates at high-altitude, at the tops of mountains and using specially designed balloons. He collaborated with Giuseppe Occhialini, H. Muirhead and young Brazilian physicist César Lattes. During the 1940s, C. F. Powell’s work led to the discovery of the pion (pi-meson). It proved to be the hypothetical particle proposed in 1935 by Yukawa Hideki in his theory of nuclear physics.
C. F. Powell became a Fellow of the Royal Society and received the society’s Hughes Medal. In 1950 he was awarded the Nobel Prize for Physics “for his development of the photographic method of studying nuclear processes and his discoveries regarding mesons made with this method”. From 1952 Powell was appointed director of several expeditions to Sardinia and the Po Valley, Italy, utilizing high-altitude balloon flights.
During the 1950s, C. F. Powell, also a member of the World Federation of Scientific Workers, added his signature to the Russell-Einstein Manifesto put forward by Bertrand Russell, Albert Einstein and scientist Joseph Rotblat, and was involved in preparations for the first Pugwash Conference on Science and World Affairs.
References and Further Reading:
- Cecil Frank Powell at the Nobel Prize Foundation Webpage
- Cecil Frank Powell at the Royal Society
- Cecil Frank Powell at Britannica Online