Patent GB-622634-A (GB)
Title: Improvements relating to high frequency electron discharge tube structure
IPC: H01J25/12
Filed: 1943-11-23
Abstract: 622,634. Velocity-modulated tubes. SPERRY GYROSCOPE CO., Inc. Nov. 23, 1943, No. 19588. Convention date, Dec. 22, 1941. [Class 39 (i)] The efficiency of bunching in a velocity-modulation tube is increased by acting upon the partiallybunched beam with a second bunching field excited by the catching field and affecting more particularly the electrons in the spaces between the bunches, so as to effect a further and sharper bunching ; a feedback is provided from the catching field to the first buncher resonator. In one form, an electron beam from cathode 1, Fig. 1, is velocitymodulated by resonator 7 and, after traversing drift tube 8, enters a frusto-conical resonator 16 of the " monotron " type (see Specification 528,041). The field in this resonator may be divided notionally into a further bunching field, in the region of entrance grid 15, and a catching field in the region of exit grid 17. The spent beam passes to inclined grid 25 which repels slow electrons and allows fast electrons to pass to collector 28 with conical impact surface 29; this collector system absorbs the D.C. energy of the spent beam while preventing the return of secondary and reflected electrons. Resonator 7 is tuned by flexible wall 10, resonator 16 by movable conductive plug 31. The feedback path includes a frequency-stabilizing resonator 35, rotatable loop 37 for amplitude control and trombone section 41 for phase adjustment. The frequency may be entirely controlled by resonator 35, resonators 7, 16 being then untuned. A density-modulating grid 45 may be provided. In a modification, Fig. 3 (not shown), resonator 16 is split up into two resonators with a short drift space between them, and coupled by a feedback path including frequency, phase and amplitude adjustment devices similar to 35, 37, 41. To eliminate deleterious effects by secondary or slow electrons entering the resonator spaces, a ring 60, Fig. 4, may be arranged between the grids 58, 59 and kept at a suitable negative potential by leads 61. To avoid high-frequency effects on the ring 60, the ratio of its capacities to grids 58, 59 is arranged to be equal to the ratio of the magnetic lines linked by each side of leads 61 ; preferably both ratios are unity. Flanges 64 by-pass highfrequency currents away from seals 62. The ring 60 also collects positive ions and has a slight focusing action. Specifications 523,712, 530,785, 531,251 and 548,725 also are referred to. The Specification as open to inspection under Sect. 91 contains also the subject-matter of Specification 622,655 and describes a further arrangement in which a magnetic field 68, Fig. 5 (Cancelled), is interposed between the second, output, resonator 48<1> and an inclined third resonator 67. The magnetic field analyses the mixed velocity beam leaving resonator 48<1> so that a sharply pulsed beam enters resonator 67. The further energy thus abstracted from the beam is fed back to output resonator 48<1>. It is also stated that all the devices may be operated as amplifiers as well as oscillators. This subject-matter does not appear in the Specification as accepted.