Person Essen; Louis (1908 - 1997) Essen Louis 1908 - 1997 British Male Nottingham, England, United Kingdom 06/09/1908 19080906 Great Bookham, Surrey, England, United Kingdom 24/08/1997 19970824

Physicist Time Atomic clocks Speed of light Radar Education: University College, Nottingham, external degree granted from University of London, BSc in physics (1928); University of London PhD (1941), DSc (1948) Career: National Physical Laboratory (1929-1972); during the second world war worked on radar, developing ways of measuring frequencies; developed a new method to determine the speed of light; developed the first practical atomic clock in collaboration with Jack Parry; advocated replacing the ephemeris second with the atomic standard, ratified by international agreement in 1968; retired 1972 Honours: OBE 1959 Medals/Awards: Wolfe award of the Department of Scientific and Industrial Research; Popov gold medal of the USSR Academy of Sciences Worked with D W Dye (FRS 1928) at NPL; married Joan Margery Greenhalgh (1937) Fellow 24/03/1960 51 Sources: Wikipedia; ODNB; PIF References: Essen, R 'The Birth of Atomic Time' (Peterborough) 2015 Essen, R 'Revolutions in Time. The World of Louis Essen, clockmaker and father of atomic time' (2020) Obituaries: Biographical Memoirs of Fellows of the Royal Society 1998 vol 44 pp 141-158, plate, by Sir Alan Cook International Standard Archival Authority Record for Corporate Bodies, Persons and Families - ISAAR(CPF) - Ottawa 1996 ISBN 0-9696035-3-3 National Council on Archives, Rules for the Construction of Personal, Place and Corporate Names, 1997 6 Sep 1908 - 24 Aug 1997 NA2141 21/11/2001 Andyg Pmab 17/12/2025 RS_NET\VirginiaM Yes http://viaf.org/viaf/78306292 181fd4cd-d74e-400b-87de-677bed04b8e0