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Boot, Henry (Albert Howard)

microwave magnetron randall power

(1917–83) British physicist: co-discoverer of the magnetron microwave generator.

Boot graduated in physics at Birmingham in 1939 and continued there in the early years of the Second World War, working with J T Randall (1905–84) on microwave generation. It was known that radiation in the microwave range (mms up to 30 cm) would be suited for radar use, to detect submarines and aircraft by reflection of radiation, but a generator of adequate power was not available. Of the several teams directed to attack the problem, Boot and Randall were given the least promising project and were understandably ‘miffed’. However, between 1939 and 1943 they devised the resonant cavity magnetron, in which pulsed electrons from a central cathode in a magnetic field, confined in a specially shaped and machined cylindrical copper block, generated 10 cm waves and 400 W power: one of its end seals was a copper coil, and joints were closed with sealing wax. GEC in the USA developed this magnetron to 10 kW power. Boot remained in this area of work, but Randall (later Sir John) moved into biophysics, afterwards directing the MRC unit at King’s College, London. Microwave devices became familiar after the Second World War in telephone communications, and police speed detectors and household cookers. Their use in cooking originated in someone leaning next to an open waveguide and finding that chocolate in his pocket had melted.

Booth, Mary Louise (1831–1889) - Popular History [next] [back] Boosey Hawkes

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