GB603570A - Gettering arrangement for electron discharge devices - Google Patents

Abstract

603,570. Electron discharge apparatus. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. Aug. 2, 1944, No. 14802. Convention date, Feb. 6, 1943. [Class 39 (i)] An electron discharge device of the magnetron type having a cylindrical chamber through which axially extends an elongated cathode surrounded by a block of conducting material having a plurality of cylindrical cavities connected to the chamber by radial slots to provide anode segments between the slots has a getter loop situated in a radio-frequency magnetic field extending between two adj acent cavities whereby the getter may be flashed by the excitation of the device. In the construction shown in Figs. 1, 2 and 4, the indirectly heated cathode 10 supported by lead and support wires 11 is axially situated in the cylindrical chamber 13 and is surrounded by the cylindrical anode block 12 of conducting material, e.g. copper, having cylindrical resonant cavities 14 connected by radial slots 15 to the chamber 13 to form a plurality of anode segments. A magnet 21 provides a magnetic field parallel to the cathode. The anode block 12 is provided at its ends with cupshaped depressions 16 and 17 into which the ends of the cathode 10 extend. The ends of the anode block are closed by conducting discs 18 and 19 sealed with a vacuum-tight seal to the block. Cooling fins 20 are secured to the outside of the anode block. The cathode leads and supports 11 are provided with extensions 22 extending through passageways and the tubular members 23 provided with elongated cup-shaped vacuum-tight sealing members 23<1> of insulating material. A coupling loop 24 mounted within one of the resonant cavities 14 is provided with a lead 25 surrounded by a coaxial threaded member 27 and a cupshaped sealing member 26 of insulating material. The coupling loop may be connected to a coaxial line cable the outer conductor of which is secured to a threaded member 27 and the inner conductor to lead 25. A getter loop 30 of U-shaped cross-section containing getter material 31 is connected at its ends 32 and 33, e.g. by welding, near the tip of an anode segment and to the wall of the cup-shaped depression 16. In operation a radio-frequency magnetic field is generated between pairs of adjacent cavities to induce a high radio-frequency current in the getter loop 30 which heats and flashes the getter material 31. After the flashing operation is completed the intensity of the magnetic field may be increased sufficiently to burn up the loop. In the modification shown in Fig. 5 the getter material 36 is contained in a closed ring 35 of U-shaped cross-section which is supported by an arm 37, welded to the wall of the cup-shaped depression 16, so as to be above the end of and coaxial with one of the resonant cavities.