Wilfrid Basil Mann (4 August 1908 – 29 March 2001) was a

radionuclide A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess nuclear energy, making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transfer ...

metrologist Metrology is the scientific study of measurement. It establishes a common understanding of units, crucial in linking human activities. Modern metrology has its roots in the French Revolution's political motivation to standardise units in Fran ...

. He was born in

Ealing Ealing () is a district in West London, England, west of Charing Cross in the London Borough of Ealing. Ealing is the administrative centre of the borough and is identified as a major metropolitan centre in the London Plan. Ealing was histor ...

, Middlesex in the

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 North ...

on 4 August 1908, receiving his

Doctorate A doctorate (from Latin ''docere'', "to teach"), doctor's degree (from Latin ''doctor'', "teacher"), or doctoral degree is an academic degree awarded by universities and some other educational institutions, derived from the ancient formalism ''l ...

Physics Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which r ...

from

Imperial College of Science and Technology Imperial College London (legally Imperial College of Science, Technology and Medicine) is a public research university in London, United Kingdom. Its history began with Prince Albert, consort of Queen Victoria, who developed his vision for a cu ...

in London in 1937. He did graduate work during the 1930s in

Copenhagen Copenhagen ( or .; da, København ) is the capital and most populous city of Denmark, with a proper population of around 815.000 in the last quarter of 2022; and some 1.370,000 in the urban area; and the wider Copenhagen metropolitan ar ...

and

Berkeley Berkeley most often refers to: *Berkeley, California, a city in the United States **University of California, Berkeley, a public university in Berkeley, California * George Berkeley (1685–1753), Anglo-Irish philosopher Berkeley may also refer ...

. While at Berkeley he worked with E.O. Lawrence on the

cyclotron A cyclotron is a type of particle accelerator invented by Ernest O. Lawrence in 1929–1930 at the University of California, Berkeley, and patented in 1932. Lawrence, Ernest O. ''Method and apparatus for the acceleration of ions'', filed: Janu ...

in the radiation laboratory and was the discoverer of the

radioisotope A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess nuclear energy, making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transferr ...

gallium Gallium is a chemical element with the symbol Ga and atomic number 31. Discovered by French chemist Paul-Émile Lecoq de Boisbaudran in 1875, Gallium is in group 13 of the periodic table and is similar to the other metals of the group (aluminiu ...

-67, which is still in use in

nuclear medicine Nuclear medicine or nucleology is a medical specialty involving the application of radioactive substances in the diagnosis and treatment of disease. Nuclear imaging, in a sense, is "radiology done inside out" because it records radiation emitting ...

. His mentor at Imperial College was

George Paget Thomson Sir George Paget Thomson, FRS (; 3 May 189210 September 1975) was a British physicist and Nobel laureate in physics recognized for his discovery of the wave properties of the electron by electron diffraction. Education and early life Thomson ...

the British physicist in charge of the Tube Alloys project during the war years (the British nuclear program that was later incorporated into 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 ...

). He had Mann assigned to the British Embassy in

Washington DC ) , image_skyline = , image_caption = Clockwise from top left: the Washington Monument and Lincoln Memorial on the National Mall, United States Capitol, Logan Circle, Jefferson Memorial, White House, Adams Morgan, ...

and to the

Chalk River Laboratory Chalk River Laboratories (french: Laboratoires de Chalk River; also known as CRL, Chalk River Labs and formerly Chalk River Nuclear Laboratories, CRNL) is a Canadian nuclear research facility in Deep River, about north-west of Ottawa. CRL is ...

in Canada. In 1951, Wilfrid Mann came to the

National Bureau of Standards The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into physical sci ...

(NBS) as the head of the Radioactivity Section. For the next 30 years Wilfrid Mann was the most influential radionuclide metrologist in the world. During the early 1950s, he had a keen interest in the national standards for

radium Radium is a chemical element with the symbol Ra and atomic number 88. It is the sixth element in group 2 of the periodic table, also known as the alkaline earth metals. Pure radium is silvery-white, but it readily reacts with nitrogen (rather t ...

-226 and undertook microcalorimetric experiments to intercompare the national standards (Hönigschmid standards) of the United States, United Kingdom, Canada, and Germany. He retired from NBS in 1980. Mann was obliged to deny claims that he was a member of the

Cambridge Spy Ring The Cambridge Spy Ring was a ring of spies in the United Kingdom that passed information to the Soviet Union during World War II and was active from the 1930s until at least into the early 1950s. None of the known members were ever prosecuted for ...

in his 1982 memoir ''Was There A Fifth Man?'' Mann had been accused on several occasions of being the "fifth man," based on rumored work at the Embassy and the resemblance between his middle name and the "Basil" of

investigative journalist Investigative journalism is a form of journalism in which reporters deeply investigate a single topic of interest, such as serious crimes, political corruption, or corporate wrongdoing. An investigative journalist may spend months or years rese ...

Andrew Boyle Andrew Philip More Boyle (27 May 1919 – 22 April 1991) was a Scottish journalist and biographer. His biography of Brendan Bracken won the 1974 Whitbread Awards and his book ''The Climate of Treason'' exposed Anthony Blunt as the "Fourth M ...

's book ''Climate of Treason''. In his memoirs, Mann argued using contemporary correspondence, publications, and verified passport entries that he was incapable of having worked with Donald Maclean in the British Embassy. As part of his hiring at the Bureau of Standards, Mann underwent intense security screening and received a top-level "Q" clearance from the

U.S. Atomic Energy Commission The United States Atomic Energy Commission (AEC) was an agency of the United States government established after World War II by U.S. Congress to foster and control the peacetime development of atomic science and technology. President ...

. Mann died in

Towson, Maryland Towson () is an unincorporated community and a census-designated place in Baltimore County, Maryland, United States. The population was 55,197 as of the 2010 census. It is the county seat of Baltimore County and the second-most populous unincorpo ...

in 2001.

Books

Mann's several texts include ''Radioactivity and Its Measurement'', 1980 (Mann, Ayres, and Garfinkel), ''A Handbook of Radioactivity Measurements Procedures'', NCRP Report 58, 1985 edition, and ''Radioactivity Measurements: Principles and Practice'', 1988 (Mann, Rytz, and Spernol).

Notes

{{DEFAULTSORT:Mann, Wilfrid Basil 1908 births 2001 deaths British nuclear physicists 20th-century British physicists Fellows of the American Physical Society