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The cavity magnetron is a high-power vacuum tube used in early radar systems and subsequently in microwave ovens and in linear particle accelerators. A cavity magnetron generates microwaves using the interaction of a stream of electrons with a magnetic field, while moving past a series of cavity resonators, which are small, open cavities in a ...
Electrically, this is similar to the two cavity oscillator klystron with considerable feedback between the two cavities. Electrons exiting the source cavity are velocity modulated by the electric field as they travel through the drift tube and emerge at the destination chamber in bunches, delivering power to the oscillation in the cavity.
Sir John Turton Randall, FRS FRSE [2] (23 March 1905 – 16 June 1984) was an English physicist and biophysicist, credited with radical improvement of the cavity magnetron, an essential component of centimetric wavelength radar, which was one of the keys to the Allied victory in the Second World War.
He was the leader of a group working on the cavity magnetron from April 1940 in north-west London. [7] The cavity magnetron was producing power of around 500W (E1188 version). Eric Megaw changed the design, coating the cathode with oxides (E1189 version) [ 8 ] and eight segments from six, to increase the power to 100 kW by September 1940 ...
Cavity magnetron at the Science Museum. From 1939 to 1943 he conducted research for the Admiralty at the University of Birmingham on centimetric radar, producing the cavity magnetron. He worked with John Randall and Harry Boot. [1] From 1943 to 1945 he was part of a group of British scientists that worked on the Manhattan Project.
A microwave cavity or radio frequency cavity (RF cavity) is a special type of resonator, consisting of a closed (or largely closed) metal structure that confines electromagnetic fields in the microwave or RF region of the spectrum. The structure is either hollow or filled with dielectric material. The microwaves bounce back and forth between ...
Among these was the magnetron, invented earlier that year by John Randall and Harry Boot. In contrast to existing systems like Chain Home that operated in the VHF meter wavelength bands, the magnetron produced a signal at 10 cm wavelength (3 GHz). The resolution of any optical system, including radars, is a function of the aperture and ...
This was developed by John Randall (1905-1984) and Harry Boot (1917-1983) at Birmingham University. Radars that could produce clear images of distant objects played a decisive role in World War II, by bouncing powerful, ultra-short radio waves off their targets. The cavity magnetron was the first practical device for producing such waves.