GB542908A - Improvements in electron discharge devices of the electronvelocity modulation type - Google Patents

Abstract

542,908. Electron oscillators. STANDARD TELEPHONES & CABLES, Ltd. July 12, 1940, No. 11635. Convention date Dec. 14, 1939. [Class 39 (i)] In an ultra high frequency amplifier or oscillation generator wherein velocity modulation of an electron beam is obtained the interior of two resonators 130, 160, Fig. 1, are connected by a drift tube with grids 133, 162 at its end and the first resonator 130 carries a tube 136 projecting towards the cathode chamber 100. The cathode 109 is supported by a pivot 103 sealed to a copper tube which is carried by a steel plate 105 bolted to another steel plate 106 with aluminium gaskets interposed ; this plate is welded to a tube 107 fixed to the wall 111. The tube 136 is mounted in the diaphragm 135 which may be flexed for tuning by the micrometer adjusting means 122 acting through the lever 120. The farther wall of the second resonator carries a grid 163 but this end may be closed by a watercooled collector plate 705, Fig. 7 ; with an open grid a water cooled collector electrode 175 receives the beam after it has given up energy in the second resonator 160. To ascertain if the tube is working efficiently some electrons from the beam are allowed to impinge on a fluorescent screen 181 passing through a hole 176 in the electrode 175, the width of the image on the screen 181 indicates the working. A concentric line 171, 172 with the loop 177 takes off power from the tubes. Back coupling between the two resonators is obtained by (i) a loop 150, Fig. 1, the amount being variable by turning the loop from the micrometer screw 154; (ii) by a loop outside the resonator ; or (iii) by two concentric lines coupled outside the resonators by a trombone slide 703, Fig. 7, or by a line which combines the coupling with the output line. A single wall 700, Fig. 7, may separate the two resonators and the whole tube may be enclosed in a water jacket. The tuning may be effected by carrying the cathode directly from the tube 501, Fig. 5, secured to the first resonator, a screw ring 502 allowing for adjustment of .the tube 501. The grids used may be formed by radiating limbs 402, Fig. 4, between concentric rings all of tantalum or cast copper. The heater for the cathode is bifilar so as to be non-inductive.