GB813105A - Velocity modulation electron discharge tubes - Google Patents

Abstract

813,105. Velocity modulated tubes. VARIAN ASSOCIATES. Aug. 10, 1955, No. 33622/57. Divided out of 813,103. Class 39(1). A velocity modulation tube preferably of the floating kidney type, has a cavity resonator and a waveguide communicating with the resonator and provided with a tuning plunger 73, Fig. 4, the waveguide having portions of its internal surface of the same cross sectional shape as and disposed close to the outer surface of the plunger and other portions of its inner cross-section spaced further from the plunger, as shown in Figs. 5, 6B. Preferably there are two plungers 73, Fig. 4, moved longitudinally by micrometer screws 85 through bellows 82 and have water cooling pipes 84, 84<SP>1</SP> separated by metal septum 80, and the drift tube and resonator wall are also provided with water cooling passages 65, 65<SP>1</SP>; 71 and Fig. 3 (not shown), 72. The plungers have <SP>#</SP>/ 4 chokes 77, 78 and have " Monel " (Registered Trade Mark) or copper rings 78 having a vitreous coating 79 which slides along the outer wall of the guide section 74. The guide may have cylindrical parts closely embracing the plunger and contacting vitreous coating 79 at the region of high electric field. If the cylindrical parts of the guide wall each have a circumferential extent of less than <SP>#</SP>/ 2 the guide-plunger structure will propagate only a TE 10 mode which is reflected back into the resonator by a <SP>#</SP>/ 4 plunger section. The plunger-guide design is such as to suppress the coaxial TEM mode and four TE modes which could exist for example with a plunger and guide of rectangular cross-section, Fig. 6A (not shown). Specifications 813,104 and 813,106 are referred to.