Bernice Weldon Sargent

Bernice Weldon Sargent, (24 September 1906 – 17 December 1993) was a Canadian physicist who worked at the Manhattan Project's Montreal Laboratory during the Second World War as head of its nuclear physics division. In his 1932 doctoral thesis, he discovered the relationship between the radioactive disintegration constants of beta particle-emitting radioisotopes and corresponding logarithms of their maximum beta particle energies. These plots are known as "Sargent curves".

Biography Bernice Weldon Sargent was born in Williamsburg, Ontario, on 24 September 1906, the son of Henry Sargent, a farmer, and his wife Ella Dillabough. He attended Chesterville High School and Morrisburg Collegiate Institute. He was awarded a Prince of Wales Entrance Scholarship and a Carter Scholarship, and entered Queen's University, where he earned a Bachelor of Arts degree with honours in mathematics and physics in 1926, and a Master of Arts degree the following year. These plots are today known as "Sargent curves" or "Sargent diagrams". This was used by Enrico Fermi in developing his theory of beta decay.

Sargent returned to Canada, where he became a lecturer and then an assistant professor at Queen's University. In 1941, he joined George Laurence of the National Research Council (NRC) in Ottawa to investigate nuclear energy, writing a report on "Uranium Fission in a Bulk of Carbon and Uranium Oxide". In 1943, he took a leave of absence from Queen's University to join the Anglo-Canadian Montreal Laboratory, which subsequently became part of the Manhattan Project. He became the head of its nuclear physics branch in 1945, and, after the laboratory moved to the Chalk River Laboratories in 1946, of the physics division in 1951. As such, he was involved in the design of the first Canadian nuclear reactors. For his wartime activities, Sargent was made a Member of the Order of the British Empire in 1946. He was awarded the Queen Elizabeth II Coronation Medal in 1953. He was survived by his wife, Dorothy.