Cecil Frank Powell
Encyclopedia
Cecil Frank Powell, FRS
(5 December 1903 – 9 August 1969) was a British
physicist
, and Nobel Prize in Physics
laureate for his development of the photographic method of studying nuclear processes and for the resulting discovery of the pion (pi-meson), a heavy subatomic particle.
Powell was born in Tonbridge
, Kent, England, the son of a local gunsmith, and educated at a local elementary school before gaining a scholarship to the Judd School, Tonbridge, which now has one of its four houses named after Powell (the house colour is green), and awards the Powell Physics and Mathematics Prize to an upper sixth form student every year in his honour. Following this he attended Sidney Sussex College, Cambridge, graduating in 1925 in the natural sciences. After completing his bachelor's degree he 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.
In 1928 he took up a post as Research Assistant to A.M. Tyndall in the H.H. Wills Physical Laboratory at the University of Bristol
, later being appointed lecturer, and in 1948 appointed Melville Wills Professor of Physics. In 1932 Powell married Isobel Artner, and the couple had two daughters. In 1936 he took part in an expedition to the West Indies as part of a study of volcanic activity, and where 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 generator
to study the scattering of atomic nuclei. He also began to develop methods 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, exposing photographic plates at high-altitude, at the tops of mountains and using specially designed balloons, collaborating in the study with Giuseppe Occhialini
, H. Muirhead and young Brazilian physicist César Lattes
. This work led in 1946 to the discovery of the pion
(pi-meson
), which proved to be the hypothetical particle proposed in 1935 by Yukawa Hideki in his theory of nuclear physics.
In 1949 Powell became a Fellow of the Royal Society and received the society's Hughes Medal the same year. 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.
In 1955, 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
. As Rotblat put it, "Cecil Powell has been the backbone of the Pugwash Movement. He gave it coherence, endurance and vitality." Powell chaired the meetings of the Pugwash Continuing Committee, often standing in for Bertrand Russell, and attended meetings until 1968.
In 1961 Powell received the Royal Medal, and served on the Scientific Policy Committee of the European Organization for Nuclear Research (CERN
) that year, and in 1967 he was awarded the Lomonosov Gold Medal
by the Academy of Sciences of the USSR (now Russian Academy of Sciences) "for outstanding achievements in the physics of elementary particles".
Powell died on 9 August 1969, whilst out walking in the foothills of the Alps near the Valsassina region of Italy, where he had been staying with friends. A bench with commemorative plaque was erected near the site of his death and dedicated to his memory.
Royal Society
The Royal Society of London for Improving Natural Knowledge, known simply as the Royal Society, is a learned society for science, and is possibly the oldest such society in existence. Founded in November 1660, it was granted a Royal Charter by King Charles II as the "Royal Society of London"...
(5 December 1903 – 9 August 1969) was a British
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
physicist
Physicist
A physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena in many branches of physics spanning all length scales: from sub-atomic particles of which all ordinary matter is made to the behavior of the material Universe as a whole...
, and Nobel Prize in Physics
Nobel Prize in Physics
The Nobel Prize in Physics is awarded once a year by the Royal Swedish Academy of Sciences. It is one of the five Nobel Prizes established by the will of Alfred Nobel in 1895 and awarded since 1901; the others are the Nobel Prize in Chemistry, Nobel Prize in Literature, Nobel Peace Prize, and...
laureate for his development of the photographic method of studying nuclear processes and for the resulting discovery of the pion (pi-meson), a heavy subatomic particle.
Powell was born in Tonbridge
Tonbridge
Tonbridge is a market town in the English county of Kent, with a population of 30,340 in 2007. It is located on the River Medway, approximately 4 miles north of Tunbridge Wells, 12 miles south west of Maidstone and 29 miles south east of London...
, Kent, England, the son of a local gunsmith, and educated at a local elementary school before gaining a scholarship to the Judd School, Tonbridge, which now has one of its four houses named after Powell (the house colour is green), and awards the Powell Physics and Mathematics Prize to an upper sixth form student every year in his honour. Following this he attended Sidney Sussex College, Cambridge, graduating in 1925 in the natural sciences. After completing his bachelor's degree he worked at the Cavendish Laboratory
Cavendish Laboratory
The Cavendish Laboratory is the Department of Physics at the University of Cambridge, and is part of the university's School of Physical Sciences. It was opened in 1874 as a teaching laboratory....
, Cambridge, under C.T.R. Wilson and Lord Rutherford, conducting research into condensation phenomena, and gaining his Ph.D. in Physics in 1927.
In 1928 he took up a post as Research Assistant to A.M. Tyndall in the H.H. Wills Physical Laboratory at the University of Bristol
University of Bristol
The University of Bristol is a public research university located in Bristol, United Kingdom. One of the so-called "red brick" universities, it received its Royal Charter in 1909, although its predecessor institution, University College, Bristol, had been in existence since 1876.The University is...
, later being appointed lecturer, and in 1948 appointed Melville Wills Professor of Physics. In 1932 Powell married Isobel Artner, and the couple had two daughters. In 1936 he took part in an expedition to the West Indies as part of a study of volcanic activity, and where 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 generator
Cockcroft-Walton generator
The Cockcroft–Walton generator, or multiplier, is an electric circuit which generates a high DC voltage from a low voltage AC or pulsing DC input...
to study the scattering of atomic nuclei. He also began to develop methods employing specialised photographic emulsions
Nuclear emulsion
In a Particle and Nuclear physics, a nuclear emulsion plate is a photographic plate with a particularly thick emulsion layer and with a very uniform grain size. Like bubble chambers, cloud chambers, and wire chambers nuclear emulsion plates record the tracks of charged particles passing through...
to facilitate the recording of the tracks of elementary particles, and in 1938 began applying this technique to the study of cosmic radiation, exposing photographic plates at high-altitude, at the tops of mountains and using specially designed balloons, collaborating in the study with Giuseppe Occhialini
Giuseppe Occhialini
Giuseppe Paolo Stanislao "Beppo" Occhialini ForMemRS was an Italian physicist, who contributed to the discovery of the pion or pi-meson decay in 1947, with César Lattes and Cecil Frank Powell . At the time of this discovery, they were all working at the H. H...
, H. Muirhead and young Brazilian physicist César Lattes
César Lattes
Cesare Mansueto Giulio Lattes , also known as Cesar Lattes, was a Brazilian experimental physicist, one of the discoverers of the pion, a composite subatomic particle made of a quark and an antiquark.-Life:Lattes was born to a family of Italian Jewish immigrants in Curitiba, Southern Brazil...
. This work led in 1946 to the discovery of the pion
Pion
In particle physics, a pion is any of three subatomic particles: , , and . Pions are the lightest mesons and they play an important role in explaining the low-energy properties of the strong nuclear force....
(pi-meson
Meson
In particle physics, mesons are subatomic particles composed of one quark and one antiquark, bound together by the strong interaction. Because mesons are composed of sub-particles, they have a physical size, with a radius roughly one femtometer: 10−15 m, which is about the size of a proton...
), which proved to be the hypothetical particle proposed in 1935 by Yukawa Hideki in his theory of nuclear physics.
In 1949 Powell became a Fellow of the Royal Society and received the society's Hughes Medal the same year. 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.
In 1955, Powell, also a member of the World Federation of Scientific Workers, added his signature to the Russell-Einstein Manifesto
Russell-Einstein Manifesto
The Russell–Einstein Manifesto was issued in London on July 9, 1955 by Bertrand Russell in the midst of the Cold War. It highlighted the dangers posed by nuclear weapons and called for world leaders to seek peaceful resolutions to international conflict...
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
Pugwash Conferences on Science and World Affairs
The Pugwash Conferences on Science and World Affairs is an international organization that brings together scholars and public figures to work toward reducing the danger of armed conflict and to seek solutions to global security threats...
. As Rotblat put it, "Cecil Powell has been the backbone of the Pugwash Movement. He gave it coherence, endurance and vitality." Powell chaired the meetings of the Pugwash Continuing Committee, often standing in for Bertrand Russell, and attended meetings until 1968.
In 1961 Powell received the Royal Medal, and served on the Scientific Policy Committee of the European Organization for Nuclear Research (CERN
CERN
The European Organization for Nuclear Research , known as CERN , is an international organization whose purpose is to operate the world's largest particle physics laboratory, which is situated in the northwest suburbs of Geneva on the Franco–Swiss border...
) that year, and in 1967 he was awarded the Lomonosov Gold Medal
Lomonosov Gold Medal
The Lomonosov Gold Medal, named after Russian scientist and polymath Mikhail Lomonosov, is awarded each year since 1959 for outstanding achievements in the natural sciences and the humanities by the USSR Academy of Sciences and later the Russian Academy of Sciences . Two medals are awarded...
by the Academy of Sciences of the USSR (now Russian Academy of Sciences) "for outstanding achievements in the physics of elementary particles".
Powell died on 9 August 1969, whilst out walking in the foothills of the Alps near the Valsassina region of Italy, where he had been staying with friends. A bench with commemorative plaque was erected near the site of his death and dedicated to his memory.
External links
- Page on Powell on the Nobel site, including biography, speeches, and lecture
- Portrait photograph of Powell at the American Institute of Physics
