James
Chadwick was born in Cheshire, England, on 20th October, 1891,
the son of John Joseph Chadwick and Anne Mary Knowles. He attended
Manchester High School prior to entering Manchester University in
1908; he graduated from the Honours School of Physics in 1911 and
spent the next two years under Professor (later Lord)
Rutherford in the Physical Laboratory in Manchester, where he
worked on various radioactivity problems, gaining his M.Sc. degree
in 1913 That same year he was awarded the 1851 Exhibition
Scholarship and proceeded to Berlin to work in the Physikalisch
Technische Reichsanstalt at Charlottenburg under Professor H.
Geiger.
During World War I, he was interned in the Zivilgefangenenlager,
Ruhleben. After the war, in 1919, he returned to England to accept
the Wollaston Studentship at Gonville and Caius College, Cambridge ,
and to resume work under Rutherford, who in the meantime had moved
to the Cavendish Laboratory, Cambridge . Rutherford had succeeded
that year in disintegrating atoms by bombarding nitrogen with alpha
particles, with the emission of a proton. This was the first
artificial nuclear transformation. In Cambridge, Chadwick joined
Rutherford in accomplishing the transmutation of other light
elements by bombardment with alpha particles, and in making studies
of the properties and structure of atomic nuclei.
He was elected Fellow of Gonville and Caius College (1921-1935) and
became Assistant Director of Research in the Cavendish Laboratory
(1923). In 1927 he was elected a Fellow of the Royal Society.
In 1932, Chadwick made a fundamental discovery in the domain of
nuclear science: he proved the existence of neutrons -
elementary particles devoid of any electrical charge. In contrast
with the helium nuclei (alpha rays) which are charged, and therefore
repelled by the considerable electrical forces present in the nuclei
of heavy atoms, this new tool in atomic disintegration need not
overcome any electric barrier and is capable of penetrating and
splitting the nuclei of even the heaviest elements. Chadwick in this
way prepared the way towards the fission of uranium 235 and towards
the creation of the atomic bomb. For this epoch-making discovery he
was awarded the Hughes Medal of the Royal Society in 1932, and
subsequently the Nobel Prize for Physics in 1935.
He remained at Cambridge until 1935 when he was elected to the Lyon
Jones Chair of Physics in the University of Liverpool. From 1943 to
1946 he worked in the United States as Head of the British Mission
attached to the Manhattan Project for the development of the atomic
bomb. He returned to England and, in 1948, retired from active
physics and his position at Liverpool on his election as Master of
Gonville and Caius College, Cambridge. He retired from this
Mastership in 1959. From 1957 to 1962 he was a parttime member of
the United Kingdom Atomic Energy Authority.
Chadwick has had many papers published on the topic of radioactivity
and connected problems and, with Lord Rutherford and C. D. Ellis, he
is co-author of the book Radiations from Radioactive substances
(1930).
Sir James was knighted in 1945. Apart from the Hughes Medal (Royal
Society) mentioned above, he received the Copley Medal (1950) and
the Franklin Medal of the Franklin Institute, Philadelphia (1951).
He is an Honorary Fellow of the Institute of Physics and, in
addition to receiving honorary doctorate degrees from the
Universities of Reading , Dublin , Leeds , Oxford , Birmingham ,
Montreal (McGill), Liverpool, and Edinburgh , he is a member of
several foreign academies, being Associé oft he Académie Royale de
Belgique; Foreign Member of the Kongelige Danske Videnskabernes
Selskab and the Koninklijke Nederlandse Akademie van Wetenschappen;
Corresponding Member of the Sächsische Akademie der Wissenschaften,
Leipzig; Member of the Pontificia Academia Scientiarum and the
Franklin Institute; Honorary Member of the American Philosophical
Society and the American Physical Society.
In 1925, he married Aileen Stewart-Brown of Liverpool. They have
twin daughters, and live at Denbigh, NorthWales. His hobbies include
gardening and fishing.
Prof. Chadwick died in 1974
From Nobel Lectures, Physics 1922-1941. |