US2944187A - Electron tube apparatus - Google Patents

Description

July 5, 1960 R. L. WALTER ETAL ELECTRON TUBE APPARATUS t TETM t L.D w w M mwm s m W u, m 5

Filed June 14, 1955 J m r v ED A r 1 July 5, 1960 R. 1.. WALTER ETAL 2,944,187

ELECTRON TUBE APPARATUS Filed June 14, 1955 8 Sheets-Sheet 2 :E II3 P/CHARD L. WAL 7'51? (14/1455 C. F/LMEI? EMA/w? H/ESTA ND 35- I IE... a N0 NIH/"0E3 ATTOEA/EV y 1960 R. L. WALTER ET ELECTRON TUBE APPARATUS Filed June 14, 1955 8 SheetsSheet 3 FII I 4:

lQ/CHAED L. WAL 7'67? 2/ JAMES C.-F/L MEE NORMA/V PHIL-STAND INVENTORS July 1960 R. 1.. WALTER EI'AL 2,944,187

ELECTRON TUBE APPARATUS Filed June 14, 1955 8 Sheets-Sheet 4 9/ 93 24 A/OEMAA/ RH/esrA/w INVENTORS r I E- 5 BY AIIOE/VEV July 5, 1960 R. 1.. WALTER ETAL 2,944,187

ELECTRON TUBE APPARATUS Filed June 14, 1955 8 Sheets-Sheet 5 P/CHAED L. WAL. 7'52 52 56 (/aMEs 0. PM M6)? July 5, 1960 R. L. WALTER ETAI- ELECTRON TUBE APPARATUS 8 Sheets-Sheet 6 Filed June 14, 1955 P/CHA 20L W4; 75E dames C. F/LMEIE E Noe/144 /v 9 M65 m/va R. L. WALTER ETAL 2,944,187 ELECTRON TUBE. APPARATUS July 5, 1960 8 Sheets-Sheet 7 Filed June 14, 1955 R505 gm H 22 M 4 5 0 Wm u r M 0 M MW A u, FUN B IIE 1E R. L. WALTER ETA]- ELECTRON TUBE APPARATUS 8 Sheets-Sheet 8 July 5, 1960 Filed June 14, 1955 hin [9/0/1450 L. W44 nae dA/wes C. H4452 &

NORMA/VPH/ESTAA/D l/VVf/WOBS ,arranles United States Patent Ofiice 2,944,118? Patented July 5, 1960 2,944,187 ELECTRON TUBE APPARATUS Richard L. Walter and James C. Filmer, Palo Alto, and

This invention relates, in general, to electron tube apparatus and, in particular, to novel electron tube apparatus of the type employing cavity resonators such as, for

example, high power klystro'n tubes utilized in systems found in radar, navigation beacons and linear accelerators, etc. i

i In the art of high frequency amplification, for example,

- that range of frequencies between 2500 and 4000 me.

there has been lacking a pulsed amplifier that would providehigh gain, that is, 55 db or over; high power, that is 1 megawatt or more with an average power of 2 kw. at the same time combining reliability and long life (1000 hours) with ease of operation.

Accordingly, it is the object of this invention to pro vide a novel high power, high gain, electron tube apparatus offering ease of operation, long life, and electrical stability.

One feature of this invention is a novel cathode electrical socket comprising a plurality of spring fingers arranged such as to receive and make electrical contact with a corresponding tube contact thereby facilitating rapid replacement of tubes.

Another feature of this invention is an output window assembly which allows the output window to be pressurized and at the same time maintain a good electrical connection under conditions ofexpansion and contraction of the electrical contact members without the use of high temperature solders thereby substantially increasing the operating life of the tube.

Other features and advantages of this invention will become apparent from a perusal of the specifications taktn in connection with the accompanying drawings wherein,

Fig. 1 is an elevational view partly in sectionshowing the assembled electron tube apparatus of this invention,

Fig. l-A is an enlarged fragmentary view of a portion of the structure of Fig. 1,

Fig. 2 is a fragmentary side elevation of the structure of Fig. 1, I

Fig. 3 is a fragmentary end view of a cavity resonator and associated parts,

Fig. 4 is a cross sectional elevational view of the cathode assembly taken along line 4-4 of Fig. 2,

Fig. 4-A is a fragmentary view of Fig. 4 showing the cathode take-apart joint, p

i Fig. 5 is an enlarged fragmentary view of the novel cathode button support. Fig. 6 is an enlarged part sectional view taken along line 66 of Fig. 2 looking in the direction of the arrows, 'Fig. 7 is an enlarged cross sectional view taken along line 7+7 of Fig. 2 looking in the direction of the arrows, Fig. 8 is a fragmentary side view partly in section showing the location of the output window assembly,

- 21 and 22 joined together at their ends.

i Fig. 8,

I assembly taken through Fig. 9 is a sectional view taken along line 9-9 of Fig. 10 is a fragmentary view taken along line 1010 of Fig. 9 showing the electrical contact and pressure seal of the output window assembly,

Fig. 11 is a fragmentary top view of the output window line 11--11 of Fig. 9,

Fig. 12 is a sectional view taken along line 12-12 of Fig. 2 looking in the direction of the arrows,

Fig. 13 is an end view of the apparatus looking in from the collector end.

The construction of the novel electron tube apparatus will now be described followed by a description of the operation and function of the apparatus.

Referring now to Fig. l, the novel tube apparatus comprises a cathode structure 1, resonators 2, 3, 4 and 5 and a collector. assembly 6. Signal energy to be amplified is supplied to the first resonator 2 via a concentric line input 7 and amplified in successive resonators 3 and 4. The amplified signal is extracted from the output resonator 5 and propagated to the load through waveguide 8. The cathode is immersed in an oil bath contained within a tank 9 to prevent arc-overs in the external cathode region. Surrounding the resonators is an electrical coil '11 for creating a strong magnetic field to confine the electron beam in the resonator region.

Referring now to Fig. 4, a source of electrons is supported from and contained within an evacuated cathode envelope 1?. Comprising the cathode envelope are a plurality of tubular segments 13, 14, 15, 16, 17, 18, 19, Of these tubular segments 16, 19 and 22 are of good insulating material as of glass to allow independent operating potentials to be applied to certain portions of the cathode assembly. Tubular segments 13 and 14 are made of materials having a high magnetic permeability as of steel to provide shielding of the cathode from magnetic fields in the cathode vicinity. The cathode envelope is closed at its lower end by a bottom cup 23 and at its upward end is securely held by pole piece 24.

.To allow the cathode assembly to be replaced a novel take-apart joint between cathode envelope segments 13 and 14 is provided (see Fig. 4-A). At the joint, proper longitudinal alignment of the lower cathode structure is obtained through the upper horizontal interface. Correct transverse alignment of the cathode is obtained through the vertical interface. interposed between these two interfaces is an area of mutually opposing surfaces which are noncontacting, that is, the opposing faces are spaced apart. These surfaces are spaced apart to create a void which destroys the capillary action tending to draw the adhesive substance 25 from its applied region through the horizontal interface and onto the vertical interface. If the void is not provided adhesive material will contaminate a greater portion of the interfaces. When the lower cathode assembly is then to be replaced, the adhesive material sticking to the aligning surfaces must be removed. Oftentimes in cleaning the adhesive from these surfaces the previously acquired alignment is destroyed. The present novel joint design allows the cathode to be removed, worked on and replaced without expending unnecessary time in cleaning the joint, meanwhile preserv- 26. The cathode flange is of heavier construction and serves to strengthen the morefragile cathode envelope. Furthermore cathode flange 26 serves as a bumper protector for the glass insulator 16. g

The novel cathode electrical socket is shown in Fig. l-A. Fixedly secured to'the annular cathode flange 26 and downwardly extending therefrom is a tubularcathode electrical contact 27 which engages a plurality of spring type electrical wipers 28 carried upon a cylindrical support lead 29 Similarly, a cup-shaped heater contact 31 is secured to the lower extremity of the cathode envelope throughheater flange .32. and extends downwardly therefrom to. engage. a plurality of heater wipers 33 carried upon a tubular heatersupply lead 34. As the tube; is inserted into the oil bath the springtype electrical wipers engage. their respective, contacts and because of the spring-tension force themselves against the contacting surface. The .leadingiedge ofsaid W-ipers' clean anarea for good electrical contact. Using the" present design it is readily seen that the time required to change at lbe is substantially reduced.

,T;he,internal1 cathode structure isshown" in detail in Fig. 4. Contained withinathe cathode envelope '12 is preferably a concave cathode emitter 35 having an annular focus ring ,36 positioned slightly in front of saidv buttonand carried by atubular focusshield 37 which in turn is. supported from the .cathode envelope by focus shield, support 39,. Fixedly secured to the cathode focus- 7 ing ring ;3,6 and extending downwardly therefrom is; a

novel tubular cathode emitter support 39 (see Fig. haying,slots runninglongitudinally thereof thereby creat ing a =plurality.offingers 41. Also carried by the focus shield-37 is, an annular double partition heat shield 42 (Eig- 4);. v

The present novel cathode construction features a cathodeemitter surrounded by a plurality of partitions all serving to retain the heat energy within the'cathode emitter region therebyvsubstantially increasing thermal efficiency. The cathode emitter support 39 is particularly unique inthatthe longitudinal slots serve to inhibit heat conductionwhile thefinger portions 41 reflect'jthe heat energy back to the cathode emitter. It hasfbeen foundthat certain fingers may be cut out to aidin evacnation. of the inner cathode regions without substantially impairingthermal efficiency. A second embodimentof" the novel cathode tem'ittersupport 39 has certain fingers bent. outwardlya'short distance to substantially a condi-' tion oficonstant. diameter for those portions of'the tubu lar member, leaving a plurality of inwardly. convergent fingers to. which. the cathode: emitter is affixed. This novel design further. prevents heat loss by conduction since: fewer fingers make contact .with the cathodeemitter. In. all embodiments the cathode emitter 35 is rigidly secured to the extremities of certainof the button support fingers. The cathode buttonsupport feature'is claimed in a copending divisional application, Serial-N0. 831,178;

Heating the cathode emitter 35, a double spiral wound filament 43 is supported upon three support rods, long heater lead 44, short heater lead 45 and center support 46.; Since center support 46: carries no current it is insulated. electrically fromthe-heater filament 43 through insulator 47. Extending into the insulator and connecting directly totne filamenn is heater support 48. Providinglbasesupports for short heaterlead 45 and filament center support. 46 aretwocircular plates, heater support flange. 49 and getter fiangefil-respectively, said flangesbeing rigidly secured to the cathode envelope '12. Longheater lead 44 extends downwardly through noncontactingopenings in heater support flange 49 and 'getter flange Sland anchors'on bottomcup 23.

. Referring now to Figs. 2- and'6, a plurality of reentr'ant typecavity resonators 2,- 3, '4 and 5 are' spaced alon g' thick walled cylindrical drift'tubes 52. spiraling around" the drift tubes is a coolin'g'coil 53 through whichis cira 4-, I} culateda coolant "to carry away heat-"generated in the drift tube vicinity. Encircling and securely aflixed to the drift tube substantially at either end thereof are two magnetic pole pieces, cathode pole piece 24 and anode pole piece 54. A plurality of stiffener plates 55 likewise encircle the drift tube and are Spaced apart in the drift tube midsection. interconnecting the pole pieces and stiffener plates are a plurality? of stifiener rods 56 which are rigidly secured to the stiffening plates as by brazing. It has been found that by utilization of the novel stiffener plates and rods the microphonic tendency of such an electron tube apparatus was substantially reduced. Moreover, electrical. talz lzi was? h hmbient tem was greatly enhanced; Because of the magnetic focusing, v not .yet fully described," the-aforementioned magnetic 1 in the cavity re'sonators and extending outwardly thereof through-anaperture in the-resonator wall. Secured to the in wardend of the tuning plunger 57 is a thin rectan gular flexible metal di'aphra'gm SS of a good electrical conducting material, for example, copper'plated Monel. The flex ible diaphragm issecured to the cavity resonator wall on two opposite edges only, the remaining two edges being:slightly spaced' from the resonator walls. Interposed -between'the outside wall of the cavity resonator and the outward extremity of the plunger extension is a bellows 59 which envelops the tuning plunger. The

bellows-is sealedatone end to the plunger and at the other *end to the outer- .wall of the cavityresonator thereby maintaining vacuum integrity within the cavitywhile-at' th'ezsame 'tirne allowing movement of the tuning plunger 51.: 7 h

Secured :to and surrounding the outward" extremity of the tu ningplunger is "a cup shapedtuning rack support 61 having attached to its outward wall "in diametrically opposedre'lation two smooth rectangular bars, tunin rac'lc support uidesos (Fi'gs;=3' a'nd7). Similarly mountedonrsaid tuning rack support 61 jand ninety degreesto said; g'uides'63 isa toothedban tuning rack 62'. Mounted on the out'wardfside ot-"the cavity end wall' and extending outwardly adjacent the'tuning raek support guides 63 istuner slide block 64 having two rectangular recesses. fii t .threin 'tfiig'ifl) -a"nd"fitted with bearing liners as of, for example, tetrafluoroethylene[resin to receive the tun ingara'ck suppo'rt"guides 63"slidzible therein; 'Actua't'ing" the tuning plunger through co'action with tuning rack 62 :isa pinion 65 -rnoui1ted on one extremity of' a tuning actuating'rod 66 which extendsthrough-an' opening in andis-held i'n positionby apinion mount 67; Operating pinion 65 and upwardly extending through apertures suitably provided in the stiffener-plates =55, actuating rod 66 (Fig. 2) further extendsthrough output pole piece 54 and terminals "in a gear case 68 '(Fig: 13-); Within the gear case and rigidly aflixed to the tuner actuating rod fis a thothed' worm' ear-'69. Interpo'sed between the toothed worm gear and t eoutputpolepieceis arectangul'an g'eai casemounting plate-71 (Figs; 7 and'3 'having'an aperture therein, the inner surfaceo the aperture form'- ingarearin -shower tiiner'actuatingrodofi; Enveloping the toothed worm gear 6 9f (1'{ig, 13 is the reci' m rff ur-s p 'e i a e W r an pe n 72 ide ou ward of the tube f (Fig. 7). 'Rotatable' a worm Shaft} 73 positioned to;

. arre rs p rate; with said toothed wormjgeari69 said wor tendingfoiitwardly of the gear'case 68 and derivapart at its free end from the drift tube ing bearing support from the inner surface of the side opening 72. Remote actuating means may be coupled to the worm shaft 73 to effectuate remote tuning of the cavity resonators. Remote tuning is often desirable in variable frequency tubes. When installed in a system gaining access to the tube may be difficult. Moreover, in some high power applications X-ray radiation from the collector can be avoided by tuning from a remote station. Thecavity tuning apparatus, above-described, is claimed in a copending divisional application, Serial No. 831,777.

Output energy (Fig. 8) is extracted from the output cavity resonator through output iris 74. Whence the energy is propagated through waveguide 8 outwardly and upwardly through output window 75 (Fig. 9) to the load. Within said. waveguide.is.a .blocking iris 76 for blocking stray secondary electrons emanating from the collector drift tube. For evacuation of the tube a pump-out adapter 77 is provided outwardly of the blocking iris and protected by an adapter cover 78.

Substantially at the end of waveguide 8 and fixedly secured thereto is the novel output window assembly comprising a rectangular flange 79 bored to receive four bolts 80 (Fig. 8). At the end of said waveguide 8 (Figs. 9 and is a second end flange 81 formed to mate with a like rectangular flange portion of a window mounting frame 82 having mounted therein the output window 75. Encircling the output window frame is a pad of good electrical conducting wire mesh 63 of suflicient thickness to cause a good electrical connection with an enveloping outer segment of waveguide 84. Said outer segment of waveguide is recessed at its lower end to form a pocket 85 for the wire pad 83 and extends upwardly of the output window. Rigidly secured to said outer segment of waveguide 84 is an output adapter flange 86 suitably bored and tapped to receive the aforementioned four bolts 80. Interposed between the lower extremity of said outer segment of waveguide 84 and said output window flange 82 and encircling said output window flange is a resilient gasket 87 as of, for example, neoprene. To prevent arc-overs and thereby increase the life of the output window it has been found helpful to pressurize the waveguide on the outward side of the Window. Because of the wide temperature fluctuations encountered, the output window frame experiences high expansion and contraction which necessitates the above novel arrangement of wire mesh and 0 ring seal, which will provide good electrical contact divhile maintaining an adequate seal.

Comprising the magnetic focusing assembly (Fig. 1) an electrical conducting coil 11 wound upon a hollow open-ended cylinder 88 encircles the drift tube midsection and is carried between two annular plates 89 and 91. The magnetic coil assembly may be rigidly mounted and the tube body comprising the cathode, cavity, drift tubes and collector assemblies may be slidably inserted into the center of the magnetic coils. Upper annular plate 89 (see Fig. 7) has a step provided on and encircling its inner circumference which mates with a similar step 92 provided on anode pole piece 54 whereby the tube body is suspended within the magnetic coils. Snugly fitting within the lower annular plate 91 (Fig. 6) is cathode pole piece 24. Encircling the outer periphery of cathode pole piece 24 is a recess carrying an O ring 93 of some resilient material, for example, neoprene, to insure that water vapors from the air do not seep through and contaminate the oil bath.

Comprising the collector assembly 6 (Fig. 7) a hollow open-ended cylindrical collector 94 carried by the drift tube 52 is closed at its upper end by a conical-shaped collector cone 95. Cut into the exterior of the cylindrical collector 94 is a helical groove thereby creating a helical land 96. Snugly fitting over the helical land is a hollow open-ended cylindrical bafiie 97 slightly spaced 52. Carrying the bafile 97 is a cylindrical coolant distributor 98 having a conical-shaped interior enveloping and being slightly spatial relationship and ferent D.C. electrical potentials in use, first and second spaced from the collector cone 95. Substantially at the upward extremity of the coolant distributor 98 is an encircling recess 99 serving as a coolant distributor ring. Carrying the coolant distributor and surrounding the collector 94 and baflie 97 is a hollow open ended cylindrical coolant jacket 101 secured to the drift tube 52 at the lower end of the said jacket. Sealed over the outward end of the coolant distributor 98 is a circular plate, collector cap 102 having water passages 103 and 104 cut thereinand fitted with quick disconnect fluid adapter 105.

In operation electronsare emitted from the cathode focused into .a beam by thelfocusing electrode 36 and accelerated through the drift tube'. The signal to be amplified is fed into the inputcavity 2 where the beam is velocity modulated. As, the modulated beam travels down the drift tube it is further modulated by the intermediate bunching cavities 3 and 4, while within the drift tube the beam is confined in diameter against forces tending to spread the beam, such as space charge forces, by the magnetic field lines supplied by the focusing coils 11, said lines of flux being parallel to the drift tube in this region. The output cavity extracts electromagnetic energy from the modulated beam and said energy is then coupled out of the output cavity through iris 74 and propagated through waveguide 8 and window 75 to the load. Tuning of the tube is obtained by a movable wall type tuning plunger which is movable within the resonator by rotation of worm shaft 73 which operates upon actuating rod 66 which in turn cooperates through pinion 65 to cause tuner rack support and attached plunger and diaphragm to move in and out of the cavity thereby changing the resonant frequency of said cavity.

Since many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. In an electron tube apparatus an output window assembly comprising a wave energy permeable material covering an opening, a flanged frame holding said permeable material, a resilient electrical conductor encircling the outer sides of said frame, a gasket encircling said frame adjacent said flange portion, an outer waveguide enveloping said resilient electrical conductor, and means for pressing said outer waveguide snugly against said gasket thereby effecting an air tight electrical conducting seal between elements which differ greatly in their eX- pansive characteristics.

2. In a high frequency apparatus, a wave energy permeable material covering an opening, a frame holding said permeable material, a resilient electrical conducting Wire mesh contacting said frame, a waveguide contacting said mesh, and sealing means providing a seal between said frame and said waveguide thereby effectuating an electrical conducting seal capable of standing high pressures without leaking between elements which differ greatly in their expansive characteristics.

3. In an electron tube apparatus a cathode electrical socket comprising a first and second hollow cylindrical conducting receptacle disposed in concentric overlapping adapted to be operated at difhollow cylindrical electrical contactor means concentrically disposed in overlapping spatial relationship fixedly carried upon the electron tube and adapted to make electrical contact with certain electrodes within the cathode assembly of the electron tube, and spring fingers carried from and outwardly tensioned of said first and second receptacles whereby when said contactors and receptacles are brought together said spring fingers cause a good electrical connection to be made between said receptacles and said contactors thereby assuring stable and reliable

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