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A cyclotron is a type of particle accelerator invented by Ernest O. Lawrence〔 〕 in 1932 in which charged particles accelerate outwards from the center along a spiral path. The particles are held to a spiral trajectory by a static magnetic field and accelerated by a rapidly varying (radio frequency) electric field. Lawrence was awarded the 1939 Nobel prize in physics for this invention.〔 Cyclotrons were the most powerful particle accelerator technology until the 1950s when they were superseded by the synchrotron, and are still used to produce particle beams in physics and nuclear medicine. The largest single-magnet cyclotron was the synchrocyclotron built between 1940 and 1946 by Lawrence at the University of California at Berkeley,〔 which could accelerate protons to 730 MeV. The largest cyclotron is the multimagnet TRIUMF accelerator at the University of British Columbia in Vancouver, British Columbia which can produce 500 MeV protons. == History == The cyclotron was invented and patented〔 by Ernest Lawrence of the University of California, Berkeley, where it was first operated in 1932.〔 〕 Lawrence went on to actually make a working cyclotron using large electromagnets from Poulsen arc radio transmitters provided by the Federal Telegraph Company.〔F.J. Mann, "Federal Telephone and Radio Corporation, A Historical Review: 1909-1946," ''Electrical Communications'' Vol. 23, No. 4 (December 1946): 397-398.〕 A graduate student, M. Stanley Livingston, did much of the work of translating the idea into working hardware.〔 (【引用サイトリンク】title=Ernest Lawrence and M. Stanley Livingston )〕 Lawrence read an article about the concept of a drift tube linac by Rolf Widerøe,〔 〕〔 〕 who had also been working along similar lines with the betatron concept. At the Radiation Laboratory of the University of California at Berkeley Lawrence constructed a series of cyclotrons which were the most powerful accelerators in the world at the time; a 4.8 MeV machine (1932), a 8 MeV machine (1937), and a 16 MeV machine (1939). He also developed a synchrocyclotron (1945). The first European cyclotron was constructed in Leningrad in the physics department of the Radium Institute, headed by . This Leningrad instrument was first proposed in 1932 by George Gamow and and was installed and became operative by 1937.〔 〕 In Nazi Germany a cyclotron was built in Heidelberg under supervision of Walther Bothe and Wolfgang Gentner, with support from the Heereswaffenamt, and became operative in 1943. 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「cyclotron」の詳細全文を読む スポンサード リンク
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