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William Alan Stewart Butement, CBE (18 August 1904 – 25 January 1990), was a defence scientist and public servant. A native of New Zealand, he made extensive contributions to radar development in Great Britain during World War II, served as the first chief scientist for the Australian Defence Scientific Service, then ended his professional career with a research position in private business. Alan Butement was born at Masterton, New Zealand, the son of New Zealand-born William Butement, physician and surgeon, and his English-born wife Amy Louise Stewart. When Alan was age eight, the family moved to Sydney, where he started at The Scots College. After a year, the family moved again, this time to London, England. He graduated from University College School and then studied at University College, University of London, where he attended lectures by Edward Victor Appleton and received the BSc degree in physics in 1926. He followed this as a research student for two years.He married Ursula Florence Alberta Parish on 17 June 1933. ==Achievements in Great Britain== In 1928, Butement joined the War Office's Signals Experimental Establishment (SEE) at Woolwich, London, as a Scientific Officer, developing radio equipment for the British Army. He and an associate, P. E. Pollard, conceived a radio apparatus for the detection of ships. A breadboard test unit, operating at 50 cm (600 MHz) and using pulsed modulation, gave successful laboratory results, but was not of interest to War Office officials. Nevertheless, in January 1931, a writeup on the apparatus was entered in the ''Inventions Book'' maintained by the Royal Engineers. This is the first official record in Great Britain of the technology that would eventually become radar.〔Butement, W. A. S., and P. E. Pollard; "Coastal Defence Apparatus", ''Inventions Book of the Royal Engineers Board'', Jan. 1931〕〔Swords, S. S.; ''tech. History of the Beginnings of Radar'', Peter Peregrinus, Ltd, 1986, pp. 71–74〕 In October 1936, Robert Watson Watt's team at Bawdsey Manor Research Centre (on the North Sea coast) was building in great secrecy Chain Home, the first full Range and Direction Finding (RDF) system, the cover name for what eventually was called radar. An Army Cell from the SEE was attached to the Bawdsey operation. Butement was among those representing the War Office. At Bawdsey, Butement was assigned to develop a Coastal Defence (CD) RDF system to be used for aiming anti-shipping and anti-aircraft guns. By early 1938, he had a prototype under test. This used a pulsed 1.5 m (200 MHz) transmitter producing 50 kW power, (later increased to 150 kW). For the transmitting and receiving antennas, he developed a large dipole array, 10 feet high and 24 feet wide, giving narrow transmitting and receiving beams. This array could be rotated at a speed around 1.5 revolutions per minute. To improve the directional accuracy, lobe-switching was used in the transmitting array.〔Butement, W. A. S., et al; "Precision Radar," ''J. Inst. Elect. Engrs.'', vol. 73, part IIIA, 1946, pp. 114–126〕 Primary credit for introducing beamed RDF systems in Great Britain must be given to Butement. As a part of this development, he formulated the first – at least in Great Britain – mathematical relationship that later became well known as the "radar range equation". In September 1939, at the start of the war, operations at Bawdsey were distributed to safer locations. The Army Cell joined the Air Defence Experimental Establishment (ADEE) at Christchurch in Dorset on the south coast. At the time of the move, Butement was named an Assistant Director of Scientific Research, and continued to lead the Coastal Defence (CD) research activity. The primary use of the evolving CD system was in aiming searchlights associated with the anti-aircraft guns, and Butement acquired the nickname of 'Mr. Searchlight Radar.' He also developed what became the standard method of determining miss-distance of gunfire against shipping by using RDF echoes from splashes caused by shells hitting the sea. There was an urgent need to improve the effectiveness of the anti-aircraft guns. With his background in radio, in October 1939 Butement turned to this technology as a potential solution. He conceived of a highly compact RDF set placed on the projectile, setting off the detonation when close proximity to the target was attained. He completed the circuit design, but there was the problem of packaging such a device in a small projectile, as well as the question of the vacuum tubes surviving the acceleration forces at firing.〔Brown, Louis; ''A Radar History of World War II'', Inst. of Physics Publishing, 1999, p. 60〕 The demands on personnel and funds at the start of the war were such that little more was done at that time. In less than a year, however, (in September 1940), Butement's concept was moved dramatically toward mass production when it was exported under the technology transfer arrangements of the Tizard Mission, and subsequently a variation of his circuit became adopted in the United States as the proximity fuse or VT (variable-time) fuse, ''the most-manufactured electronic device of the war''. In the later stages of the war, anti-aircraft shells fitted with proximity fuses played a major part in defeating both German V-1 flying bomb attacks on London, and Japanese ''kamikaze'' attacks on Allied shipping. As well as the dramatic breaking of Japanese Naval air power in the Battle of the Philippine Sea, it immortalised the invention's impact with the battle's alternate name: ''The Great Marianas Turkey Shoot'', where the battle losses were so severe that it led to the Japanese adoption of the kamikaze. Years later, Butement said that he considered the proximity fuse as his most significant accomplishment. As the war got under way, it was realised that the Chain Home (CH) system needed an additional ability to detect low-flying aircraft. The CD RDF was ideal for this function, and was soon added at most CH stations as the Chain-Home Low (CHL). For making the necessary adaptations, Butement led the effort at the Air Defence Experimental Establishment (ADEE). In February 1940, Harry Boot and John Randall at Birmingham University built a high-power cavity magnetron, allowing signal-generation at microwave frequencies.〔Megaw, Eric C. S.; "The High-Power Magnetron: A Review of Early Developments,” ''J. of the IEE'', vol. 93, 1948, pp. 977–984〕 In the autumn of 1940, the device was brought to America by the Tizard Mission, and development of microwave radars was started on both sides of the Atlantic. (The Tizard Mission also brought back to Great Britain the name 'radar' – adopted as a cover by the US Navy in 1940.) The ADEE was reformed into the Air Defence Research and Development Establishment (ADRDE) in mid-1941. Applications of the CD system and the work of Butement were even more important as microwave devices were added. Germany began bomber attacks on the British mainland, and it was decided that radar research and development activities would be moved further inland. In May 1942, the ADRDE was transferred to Malvern, Worcestershire, where it remained for many years. In 1943, Butement, then Assistant Director of Scientific Research with the Ministry of Supply, invented and supervised the development of a secure radio-based method of battlefield communication using narrow beams of pulsed microwave signals, to replace the traditional telephone cable. Using a 10 cm (3 GHz) transmitter and receiver developed for radar, the Wireless Station No. 10 evolved. Called one of the electronic wonders of WWII, this was the first multi-channel, microwave communication system in Great Britain. It first went operational in July 1944, just after D-Day, and served as the central communications backbone for the British march across Europe to victory.〔Anon.; "Multi-Channel Pulse Modulation: details of the Army Wireless Station No.10", ''Wireless World'', June 1946, pp. 187–192〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「W. A. S. Butement」の詳細全文を読む スポンサード リンク
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