Egon Bretscher CBE (1901–1973) was a Swiss-born British chemist and nuclear physicist and Head of the Nuclear Physics Division from 1948 to 1966 at the

Atomic Energy Research Establishment The Atomic Energy Research Establishment (AERE) was the main centre for atomic energy research and development in the United Kingdom from 1946 to the 1990s. It was created, owned and funded by the British Government. A number of early res ...

, also known as

Harwell Laboratory The Atomic Energy Research Establishment (AERE) was the main centre for atomic energy research and development in the United Kingdom from 1946 to the 1990s. It was created, owned and funded by the British Government. A number of early res ...

, in Harwell,

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and ...

. He was one of the pioneers in

nuclear fission Nuclear fission is a reaction in which the nucleus of an atom splits into two or more smaller nuclei. The fission process often produces gamma photons, and releases a very large amount of energy even by the energetic standards of radio ...

research and one of the first to foresee that plutonium could be used as an energy source. His work on nuclear physics led to his involvement in the British atomic bomb research project

Tube Alloys Tube Alloys was the research and development programme authorised by the United Kingdom, with participation from Canada, to develop nuclear weapons during the Second World War. Starting before the Manhattan Project in the United States, the ...

and his membership of the

British Mission to the Manhattan Project Britain contributed to the Manhattan Project by helping initiate the effort to build the first atomic bombs in the United States during World War II, and helped carry it through to completion in August 1945 by supplying crucial expertise. Fol ...

at Los Alamos, where he worked in

Enrico Fermi Enrico Fermi (; 29 September 1901 – 28 November 1954) was an Italian (later naturalized American) physicist and the creator of the world's first nuclear reactor, the Chicago Pile-1. He has been called the "architect of the nuclear age" an ...

's Advanced Development Division in the F-3 Super Experimentation group. His contributions up to 1945 are discussed by

Margaret Gowing Margaret Mary Gowing (), (26 April 1921 – 7 November 1998) was an English historian. She was involved with the production of several volumes of the officially sponsored ''History of the Second World War'', but was better known for her books ...

in her "''Britain and Atomic Energy'', 1935-1945."

Early life

Born near Zurich, Switzerland and educated at the Eidgenössische Technische Hochschule (ETH) there, Bretscher gained a PhD degree in organic chemistry at

Edinburgh Edinburgh ( ; gd, Dùn Èideann ) is the capital city of Scotland and one of its 32 Council areas of Scotland, council areas. Historically part of the county of Midlothian (interchangeably Edinburghshire before 1921), it is located in Lothian ...

in 1926. He returned to Zurich as privat docent to

Peter Debye Peter Joseph William Debye (; ; March 24, 1884 – November 2, 1966) was a Dutch-American physicist and physical chemist, and Nobel laureate in Chemistry. Biography Early life Born Petrus Josephus Wilhelmus Debije in Maastricht, Netherland ...

, later moving in 1936 to work in Rutherford’s laboratory at the

Cavendish Cavendish may refer to: People * The House of Cavendish, a British aristocratic family * Margaret Cavendish (1623–1673), British poet, philosopher, and scientist * Cavendish (author) (1831–1899), pen name of Henry Jones, English au ...

in Cambridge as a Rockefeller Scholar. Here he switched to research in

nuclear physics Nuclear physics is the field of physics that studies atomic nuclei and their constituents and interactions, in addition to the study of other forms of nuclear matter. Nuclear physics should not be confused with atomic physics, which studies t ...

, proposing (with Norman Feather) in 1940 that the 239 isotope of element 94 could be produced from the common isotope of

uranium-238 Uranium-238 (238U or U-238) is the most common isotope of uranium found in nature, with a relative abundance of 99%. Unlike uranium-235, it is non-fissile, which means it cannot sustain a chain reaction in a thermal-neutron reactor. However ...

neutron capture Neutron capture is a nuclear reaction in which an atomic nucleus and one or more neutrons collide and merge to form a heavier nucleus. Since neutrons have no electric charge, they can enter a nucleus more easily than positively charged protons ...

and that, like

U-235 Uranium-235 (235U or U-235) is an isotope of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238, it is fissile, i.e., it can sustain a nuclear chain reaction. It is the only fissile isotope that exist ...

, this should be able to sustain a

nuclear chain reaction In nuclear physics, a nuclear chain reaction occurs when one single nuclear reaction causes an average of one or more subsequent nuclear reactions, thus leading to the possibility of a self-propagating series of these reactions. The specific nu ...

. A similar conclusion was independently arrived at by

Edwin McMillan Edwin Mattison McMillan (September 18, 1907 – September 7, 1991) was an American physicist credited with being the first-ever to produce a transuranium element, neptunium. For this, he shared the 1951 Nobel Prize in Chemistry with Glenn Seab ...

and

Philip Abelson Philip, also Phillip, is a male given name, derived from the Greek (''Philippos'', lit. "horse-loving" or "fond of horses"), from a compound of (''philos'', "dear", "loved", "loving") and (''hippos'', "horse"). Prominent Philips who popularize ...

Berkeley Radiation Laboratory Lawrence Berkeley National Laboratory (LBNL), commonly referred to as the Berkeley Lab, is a United States national laboratory that is owned by, and conducts scientific research on behalf of, the United States Department of Energy. Located in ...

. In addition, he devised theoretical chemical procedures for purifying this unknown element away from the parent uranium; this element was named

plutonium Plutonium is a radioactive chemical element with the symbol Pu and atomic number 94. It is an actinide metal of silvery-gray appearance that tarnishes when exposed to air, and forms a dull coating when oxidized. The element normally exh ...

Nicholas Kemmer Nicholas Kemmer (7 December 1911 – 21 October 1998) was a Russian-born nuclear physicist working in Britain, who played an integral and leading edge role in United Kingdom's nuclear programme, and was known as a mentor of Abdus Salam – a N ...

. Bretscher used to joke that his main contribution to physics occurred in the summer of 1930, when he was climbing in the Bergel region near

Engadin The Engadin or Engadine ( rm, ;This is the name in the two Romansh idioms that are spoken in the Engadin, Vallader and Puter, as well as in Sursilvan and Rumantsch Grischun. In Surmiran, the name is ''Nagiadegna'', and in Sutsilvan, it is ...

with another student,

Felix Bloch Felix Bloch (23 October 1905 – 10 September 1983) was a Swiss-American physicist and Nobel physics laureate who worked mainly in the U.S. He and Edward Mills Purcell were awarded the 1952 Nobel Prize for Physics for "their development of new ...

, in the

Swiss Alps The Alpine region of Switzerland, conventionally referred to as the Swiss Alps (german: Schweizer Alpen, french: Alpes suisses, it, Alpi svizzere, rm, Alps svizras), represents a major natural feature of the country and is, along with the Swis ...

. Bloch slipped over an icy edge but was saved, as he fell, by the rope joining him to Bretscher. The latter's swift action in driving his ice axe into the ice prevented their combined demise. After raising the alarm, Bretscher returned with a guide and spent the night with Bloch discussing physics. It took guides a further three days to bring Bloch down. Bloch later won the

Nobel Prize The Nobel Prizes ( ; sv, Nobelpriset ; no, Nobelprisen ) are five separate prizes that, according to Alfred Nobel's will of 1895, are awarded to "those who, during the preceding year, have conferred the greatest benefit to humankind." Alfr ...

for physics for his discovery of

nuclear magnetic resonance Nuclear magnetic resonance (NMR) is a physical phenomenon in which nuclei in a strong constant magnetic field are perturbed by a weak oscillating magnetic field (in the near field) and respond by producing an electromagnetic signal with a ...

Manhattan Project

In 1944 he became a part of the British Mission to the

Manhattan Project The Manhattan Project was a research and development undertaking during World War II that produced the first nuclear weapons. It was led by the United States with the support of the United Kingdom and Canada. From 1942 to 1946, the project w ...

Los Alamos, New Mexico Los Alamos is an census-designated place in Los Alamos County, New Mexico, United States, that is recognized as the development and creation place of the atomic bomb—the primary objective of the Manhattan Project by Los Alamos National Labo ...

led by

James Chadwick Sir James Chadwick, (20 October 1891 – 24 July 1974) was an English physicist who was awarded the 1935 Nobel Prize in Physics for his discovery of the neutron in 1932. In 1941, he wrote the final draft of the MAUD Report, which inspi ...

, where he made the first measurements on the energy released in fusion processes. During his time in Los Alamos, he took many

Kodachrome Kodachrome is the brand name for a color reversal film introduced by Eastman Kodak in 1935. It was one of the first successful color materials and was used for both cinematography and still photography. For many years Kodachrome was widely used ...

slides which appear to constitute a unique coloured record of that research site. His pictures, which are now held by the

Churchill Archives Centre The Churchill Archives Centre (CAC) at Churchill College at the University of Cambridge is one of the largest repositories in the United Kingdom for the preservation and study of modern personal papers. It is best known for housing the papers of ...

, include photographs of

Edward Teller Edward Teller ( hu, Teller Ede; January 15, 1908 – September 9, 2003) was a Hungarian-American theoretical physicist who is known colloquially as "the father of the hydrogen bomb" (see the Teller–Ulam design), although he did not care for ...

and the

Trinity The Christian doctrine of the Trinity (, from 'threefold') is the central dogma concerning the nature of God in most Christian churches, which defines one God existing in three coequal, coeternal, consubstantial divine persons: God th ...

site in New Mexico after the first atomic bomb was detonated, showing the surface light brown sand turned to a green-blue glass.

Harwell Laboratory

In 1947 he was invited by John Cockcroft to head the Chemistry Division at the newly established

Harwell, Oxfordshire Harwell is a village and civil parish in the Vale of White Horse about west of Didcot, east of Wantage and south of Oxford. The parish measures about north – south, and almost east – west at its widest point. In 1923 its area was . Hi ...

, England and in 1948 succeeded

Otto Frisch Otto Robert Frisch FRS (1 October 1904 – 22 September 1979) was an Austrian-born British physicist who worked on nuclear physics. With Lise Meitner he advanced the first theoretical explanation of nuclear fission (coining the term) and first ...

as head of the Nuclear Physics Division there. Amongst his colleagues were Bruno Pontecorvo in the Nuclear Physics Division, and

Klaus Fuchs Klaus Emil Julius Fuchs (29 December 1911 – 28 January 1988) was a German theoretical physicist and atomic spy who supplied information from the American, British and Canadian Manhattan Project to the Soviet Union during and shortly af ...

who was the head of the Theoretical Physics Division. He was appointed a Commander of the Most Excellent Order (CBE) on retirement from Harwell. Bretscher died in Switzerland in 1973. Of his two daughters and three sons, Scilla Senior was a computer programmer, Mark Bretscher and Anthony Bretscher are cell biologists, whilst Peter Bretscher is an immunologist.

References

{{DEFAULTSORT:Bretscher, Egon 1901 births 1973 deaths Alumni of the University of Edinburgh Swiss nuclear physicists Swiss physicists Manhattan Project people People associated with the nuclear weapons programme of the United Kingdom Commanders of the Order of the British Empire Fellows of the American Physical Society Swiss emigrants to the United Kingdom