Cecil Frank Powell

Education Cecil Frank Powell was born on 5 December 1903 in Tonbridge, England, the son of Frank Powell, a gunsmith, and Elizabeth Caroline Bisacre. Powell was educated at a local primary school, before gaining a scholarship to The Judd School. He entered Sidney Sussex College, Cambridge, graduating in 1925 with First Class Honours in the Natural Sciences Tripos. He then worked under Ernest Rutherford and C. T. R. Wilson in the Cavendish Laboratory, and received his Ph.D. in Physics in 1927.

In 1932, Powell married Isobel Therese Artner (1907–1995). They had two daughters, Jane and Annie. In 1936, he took part in a Royal Society expedition to Montserrat in the West Indies as part of a study of a damaging earthquake swarm. He appears on a stamp issued in Grenada.

During his time at Bristol University, Powell applied himself 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–Walton generator to study the scattering of atomic nuclei. collaborating in the study with Giuseppe Occhialini, Hugh Muirhead, and César Lattes. This work led in 1947 to the discovery of the pion (pi-meson), which proved to be the hypothetical particle proposed in 1935 by Hideki Yukawa in his theory of nuclear forces.

In 1950, Powell was awarded the Nobel Prize in Physics "for his development of the photographic method of studying nuclear processes and his discoveries regarding mesons made with this method." Debendra Mohan Bose and Bibha Chowdhuri published three consecutive papers in Nature, but could not continue further investigation on account of "non-availability of more sensitive emulsion plates" during the war years.

Seven years after this discovery of mesons by Bose and Chowdhuri, Powell made the same discovery of pions and muons and further decay of muons to electrons… using the same technique". He acknowledged in his book, "In 1941, Bose and Chaudhuri (sic) had pointed it out that it is possible, in principle, to distinguish between the tracks of protons and mesons in an emulsion… They concluded that many of the charged particles arrested in their plates were lighter than protons, their mean mass being … the physical basis of their method was correct and their work represents the first approach to the scattering method of determining momenta of charged particles by observation of their tracks in emulsion". In fact, the measured mass of the particle by Bose and Chowdhuri was very close to the accepted value measured by Powell who used improved "full-tone" plates. From 1952, Powell was appointed director of several expeditions to Sardinia and the Po Valley, Italy, utilizing high-altitude balloon flights. added his signature to the Russell–Einstein Manifesto put forward by Bertrand Russell, Albert Einstein, and Joseph Rotblat, and was involved in preparations for the first Pugwash Conference on Science and World Affairs.

In 1961, Powell served on the Scientific Policy Committee of the European Organization for Nuclear Research (CERN). As a result, for the first time in human history, a World Constituent Assembly convened to draft and adopt the Constitution for the Federation of Earth.

Death Memorial bench dedicated to Powell outside the Capanna Vittoria restaurant, on the Alpe Giumello in Casargo, Italy.

On 9 August 1969, Powell died of a heart attack while on holiday with his wife in the Valsassina region of Italy, lodging in a house in Sanico, in the Province of Lecco.

Giuseppe Occhialini had a wooden bench built with Powell's name carved into a commemorative plaque, and then transported it to Premana, a village in the mountains above Lake Como. It was installed on the path where he died, outside the Rifugio Capanna Vittoria (now the Capanna Vittoria restaurant), on the Alpe Giumello, in Casargo.

Awards Year Organisation Award Citation 1949 Royal Society Hughes Medal "For his distinguished work on the photography of particle tracks, and in connexion with the discovery of mesons and their transformation." 1950 Royal Swedish Academy of Sciences Nobel Prize in Physics "For his development of the photographic method of studying nuclear processes and his discoveries regarding mesons made with this method." 1967 Academy of Sciences of the Soviet Union Lomonosov Gold Medal "For outstanding achievements in the field of elementary particle physics."

Commemoration The Cecil F. Powell Memorial Medal was named in his honour by the European Physical Society. In October 2011, a replacement commemorative plaque was installed in Downside Road, Bristol. In 2013, the International Inner Wheel Club of Lecco, in Lombardy, Northern Italy, erected a sign in memory of Powell, close to where he died, at the Capanna Vittoria restaurant, on the Alpe Giumello, in Casargo.