James Chadwick

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James Chadwick c. 1945

Sir James Chadwick (born October 20, 1891 in Bollington , Cheshire East , † July 24, 1974 in Cambridge ) was an English physicist . He was a Nobel Prize laureate in physics in 1935. He received the Nobel Prize for the discovery of the neutron .

Live and act

Chadwick was born in 1891 in Bollington , near Manchester . His parents were John Joseph Chadwick and Mary Anne Knowles. He attended the Bollington Cross C of E Primary School and later the Central Grammar School for Boys in Manchester. In 1908 he began studying physics at the University of Manchester, where he graduated in 1911. Chadwick then spent two years with Ernest Rutherford at the Physical Laboratory in Manchester, where he worked on various problems relating to radioactivity. In 1913 a Master of Science (M.Sc.) degree in this area followed. In the same year he won a scholarship ("1851 Senior Research Scholarship") and went to the Physikalisch-Technische Reichsanstalt in Berlin-Charlottenburg as an employee of Hans Geiger .

After the outbreak of World War I in 1914, he was interned . During his imprisonment in the “civil prisoner camp” in Ruhleben , however, he was still able to carry out his own experiments, albeit with significant restrictions. After returning to England and Rutherford taking over the management of the Cavendish Laboratory in 1919, he became its close associate and assistant director of the institute. Together they worked on researching gamma radiation and the structure of the atomic nucleus .

Bunsentagung Münster 1932, Chadwick sitting left

In 1932, by bombarding beryllium atoms with alpha particles , Chadwick succeeded in providing experimental evidence for the existence of the neutron , which had been predicted since research into the isotopes in the 1920s. He published an article in the journal Nature on February 27, 1932 about his research into the existence of the neutron. In 1935 he received the Nobel Prize in Physics for his work . The work paved the way for Enrico Fermi's , Otto Hahn and Fritz Straßmann's experiments on the induced fission of nuclei of the element uranium through bombardment with neutrons and the possibility of a nuclear chain reaction . Chadwick then devoted himself to building a cyclotron at Liverpool University , where he was Lyon Jones Professor of Physics from 1935 .

With the help of the device, it was possible to prove in 1940 that a few kilograms of enriched uranium would be sufficient for the production of an atomic bomb , not the previously estimated amount of at least one ton. Chadwick was a member of the MAUD commission , which discussed whether the construction of a nuclear weapon was possible. He later wrote: " I realized that a nuclear bomb was not only possible, it was inevitable " - I realized that a nuclear bomb was not only possible, but that it would inevitably come . And further: " I had then to start taking sleeping pills. It was the only remedy. “- From then on I had to take sleeping pills; without it no longer worked. Together with other British scientists, Chadwick worked in this MAUD commission on the construction of such a weapon, which counted on the availability of a British nuclear weapon by 1943. A corresponding plant for the production of weapons-grade material was built in Canada.

After the USA entered the war in December 1941, the American government also stepped up its efforts to build a nuclear weapon. In 1943 the governments of the two countries decided to coordinate their nuclear programs. Together with other British scientists, Chadwick was sent to the USA to work on the Manhattan Project . He headed the British mission at the Manhattan Project and stayed there until 1946. The uranium produced in Canada was used for further research and thus contributed to the completion of the first atomic bomb. In 1945, Chadwick was knighted for his services.

After the end of the war, Chadwick returned to Liverpool and helped set up the British nuclear energy program. He also pushed through the construction of a synchrotron at the university there and played a major role in the British decision to participate in the establishment of the European nuclear research center CERN . In 1948 he resigned from his professorship in Liverpool and became a master at Gonville and Caius College at Cambridge University . In 1958 he retired from the university and lived in Liverpool for a few years. In 1966 he was inducted into the Order of Pour le Mérite and in 1969 he retired in Cambridge. He died in 1974 at the age of almost 83.

In Chadwick's honor, the now obsolete unit of neutron flux, the Chad , was named after him.

A moon crater was also named after him.

literature

  • Andrew Brown: The neutron and the bomb. A biography of Sir James Chadwick . Oxford University Press, Oxford 1997, ISBN 0-19-853992-4 .
  • Michael F. L'Annunziata: James Chadwick (1891-1974) . In: Radioactivity: introduction and history . Elsevier, 2007, ISBN 978-0-444-52715-8 , pp. 217 ff . ( limited preview in Google Book Search [accessed June 1, 2010]).

Web links

Commons : James Chadwick  - Collection of Images, Videos and Audio Files

Individual evidence

  1. ^ Andrew Brown: The neutron and the bomb: a biography of Sir James Chadwick . Oxford University Press, 1997, ISBN 978-0-19-853992-6 , pp. 4 .
  2. ↑ James Chadwick. The Nobel Prize in Physics 1935. The Nobel Foundation, 1935, accessed June 1, 2010 .
  3. ↑ a b Mark Oliphant: The beginning: Chadwick and the neutron . In: Bulletin of the Atomic Scientists . tape 38 , no. 10 . Educational Foundation for Nuclear Science, Inc., 1982, p. 14 ( limited preview in Google Book Search [accessed June 1, 2010]).
  4. ^ J. Chadwick, ES Bieler: The collisions of α particles with hydrogen nuclei . In: Philosophical Magazine Series 6 . tape 42 , no. 252 , 1921, pp. 923-940 , doi : 10.1080 / 14786442108633834 (indication of strong interaction).
  5. ↑ James Chadwick: Possible Existence of a Neutron . In: Nature . tape 129 , no. 3252 , February 27, 1932, p. 312 , doi : 10.1038 / 129312a0 ( online [accessed June 29, 2013]).
  6. ↑ James Chadwick: The Existence of a Neutron . In: Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character . tape 136 , no. 830 , May 1, 1932, p. 692–708 ( online ( memento of October 24, 2005 in the Internet Archive ) [accessed June 1, 2010]).
  7. ^ List of members: Sir James Chadwick in: Orden pour le Mérite for Sciences and Arts, 1842-2002 , Bleicher Verlag, Gerlingen, 2002, ISBN 3-88350-175-1
  8. ^ Chadwick (moon crater) in the Gazetteer of Planetary Nomenclature of the IAU (WGPSN) / USGS
personal data
SURNAME Chadwick, James
BRIEF DESCRIPTION English physicist
DATE OF BIRTH October 20, 1891
PLACE OF BIRTH Manchester
DATE OF DEATH July 24, 1974
Place of death Cambridge