US2456861A - Generator and cathode construction for electricity of ultra high frequency - Google Patents

Description

2,456,861 FOR 2 Sheets-Sheet 1 Filed May 6, 1945 ll] IIIIIIV INVENTOR wwuh ATTORNEY J.-M. CARTER GENERATOR AND CATHODE CONSTRUCTION FOR ELECTRICITY OF ULTRA HIGH FREQUENCY Dec. 21, 1948.

2 Sheets Sheet 2 Filed May 6, 1943 INVENTOR WWW ATTORNEY ?atentecl Dec. 21, 1948 GENERATOR AND CATHODE CONSTRUC- TION FOR ELECTRICITY OF HIGH FREQUENCY John M. Carter, Baltimore, Md, assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application May 6, 1943, Serial No. 485,852

14 Claims.

This invention relates to generators for electricity of ultra-high frequency, and more particularly, to the general construction of such and the cathode mounts thereof.

The primary objects of my invention, generally considered, are to provide a novel form of generator for electricity of ultra-high frequency and a cathode mount therefor involving a heater element, a cathode proper, a shield, a grid, and a focusing ring, all so arranged that they may be made cheaper, easier and better than previous similar devices, with a reduction in the number of operations, and the avoidance of interior contamination due to sealing, whereby they are more readily adapted to production methods and require fewer jigs and parts.

Another object of my invention is to provide a cathode mount for ultra-high frequency devices, involving a heat shield which supports an associated grid and focusing ring adjacent its upper end, and which is adapted to be assembled, quickly and accurately, with an insulative cathode support, a cathode cup, and heater filament.

A further object of my invention is to provide a generator for electricity of ultra-high frequency having an electron-emissive-cathode mount, an envelope consisting in part of a cavity resonator device associated with said mount, with the latter involvin an insulative base, a cathode cup member telescoped with a portion of said base and supported on the upper surface thereof, leads for the cup and filament passing through said base, a cathode shield telescoped with said base portion, and a grid and focusing ring supported on the upper end of said shield.

A still further object of my invention is to manufacture reflex Klystrons from standard receiving-type metal tube parts, instead of special parts prepared for the individual tube, thus eliminating a large quantity of glass, Kovar and other critically needed materials and equipment.

An additional object of my invention is the manufacture of devices, such as reflex Klystrons, with the elimination of the eight-lead lass dish stem as the weakest element of such.

Another object of my invention is to eliminate poisoning of the cathode and general contamination of the inside of the tube, due to sealing with fires, by assembling and brazing the device in a hydrogen atmosphere.

A still further object of my invention is to more accurately align the cathode and refletcor in a reflex Klystron by using a novel method of manu- ULTRA facture in order to provide such devices with greater efficiency and power output.

Other objects and advantages of the invention, relating to the particular arrangement and construction of the various parts, will become apparent as the description proceeds,

Referring to the drawing illustrating the invention:

Fig. 1 is a fragmentary axial sectional view of an electron beam device for generating electricity of ultra-high frequency and involving one embodiment of the invention, portions thereof being shown in elevation.

Fig. 2 is a fragmentary transverse sectional View on the line II-II of Fig. l, in the direction of the arrows.

Fig. 3 is a fragmentary transverse sectional view on the line III-III of Fig. 1, in the direction of the arrows.

Fig. 4 is an exploded view of the cathode mount.

Fig. 5 is a fragmentary axial sectional view, similar to Fig. 1, but showing a modification,

Fig. 6 is a transverse sectional View on the line VIVI of Fig. 5, in the direction of the arrows.

Fig. 7 is an axial sectional view, partly in elevation, showing parts of the device during manufacture.

Fig. 8 is a transverse sectional view corres-- ponding to Fig. '7 but showing other parts of the device during manufacture.

Referring to the drawing in detail, and first considering the embodiment of my invention illustrated in Figs 1 to 4, inclusive, the reference numeral I designates the generator orreflex Klystron, in general. The numeral H designates the cathode mount construction in general, which is supported within an evacuated envelope 52, generally circular in cross-section, on an insulator l3, held in place by supporting leads M, 15, i6 and I1 which pass through the lower end of the envelope. The manner in which these leads support the insulator 13, which may be formed of porcelain, is shown most clearly in Figs. 1 and 4, that is, they desirably have collars l8 secured to intermediate portions thereof which act as stops for the insulator l3, said insulator being held in place on the upper end portions of said leads by collar devices is, after insertion of said leads through corresponding apertures 25,

The insulator It comprises a lower plate portion 22, generally circular in outline, from which etxends a generally cylindrical portion 23 coaxial therewith, and terminating at its upper end in a coaxial cylindrical projection 24 of smaller size. The projection 24 desirably supports a reflector plate 25, through which and the insulator l3 extend leads 26 and 2'! for the cathode-heating filament 28. The cathode proper is in the form of a downwardly opening cup member 29, of nickel or other suitable metal, carrying on its upper or closed end, electron-emissive material 3!, such asa mixture .of oxidesiofbarium and strontium.

Said cathode 29 carries support wires 32 and the former of which merely passes through a corresponding aperture 34 inthe insulator I3 and is secured in place by meansof collar. 35, while the other passes through corresponding aperture 36, is secured in place by asimilarcollarfi'l, and

continues on to unite with'cathode-lead .wire=3 8 which passes out of the envelope in adirection' parallel to the leads M to ll, inclusive. The heater filament leads 26 and-2'i 1ikewise respectively unite with leads 39 and K6, the former of which has a getter device 4| carried between it and associated lead 42, which latterpasses out of t the envelope 'likethe leads. id to I l, inclusive, [t8

and 38.

The cathode mount also includes a heat shield '43 which telescopes with the cylindrical portion 23 of the insulator t3, andis desirably clamped in I place by bendingits ;lower edge portion intoxthe groove 44 at thebase thereof. The heat shield 23 carries a lead A5, whichpasses through corresponding alperture '46 intheinsulator l3 and then connects with the lead-in conductor 15, and

wires 38 and-'50. Ihelower or free ends of said wiresii] andSB are desirably' bent after assembly to holdingpositicns, as shown mostclearly in Fig; 2.

In the present embodiment, the upper end of the heat shield 13 carries a grid ,4], theperipheral portionof whichis flanged as indicated at .48, and telescopes over the upper end of said shield. Said grid isdesirably held in place by the focusing ring d9 consisting of a cylindrical. bodyportion 5! flanged inwardly, as indicated-at 15,2 Said inwardly projectin plane ,annularfiange 5,2 terminates in .a downwardly projecting cylindrical flange Ell which telescopes ,over thedownwardly dependingjfianged portion 48 of thegrid 41. All three parts may be secured together by running solder into the space between thetelescoping .portions thereof.

l he envelope portionl2 ,iscompleted bythe metal cylindrical portion.53, whichmay be of Kovar, which is a well-known nickel-cobaltiron alloy more specifically defined inthe Lempert et al. Patent No. 2,279,831, dated April 14, 1942, or other material which .unitesreadily with the glass of the lead-in conductor carrying portion I2. Said cylindrical portion 53 is connected to a flange element 54 at its upper end, which in turn carries an annular plate and cylindrical flange member 55, having gridsbii and 57, and being united to a flexible wall. 58 .of a cavity resonator device Bil, The upper wallfil .of the resonator 59 also carries agrid 62 and portions which may be conventional to complete theen-velope and support a refiector63, as by means of leadin conductor 89. In operation, suitable power sources are connected, ,as through the various leads disclosed, so that a beam of electrons from the cathode 29, due to. heating it by means of its preferably tungsten filament 28, .shallpass successively throughthe grids 41,156, 51 and 62, to be reversed'by the reflector 63, held in place in any desired manner, oras disclosed in Fig. 5, and

directed back through the cavity resonator device .59, to.enfect-lgenerationof the desiredpowenas :hetweenthe grids 5i and 62, giving up energy whilev passing back therethrough in bunches on the reflected or-return path, Tuning of the resonant'chamberfi may, therefore, be obtained by ,.changi ng the space between the grids 5'1 and 62 and the distance between the walls 58 and GI,

- in any desiredmanner, or as illustrated in Fig. 5, by virtue of the flexibility of the wall 58, which is desirably provided with corrugations concentric about .the tube axis. The generated energymay be Withdrawn by the coaxial line 5. using the loop device 65.

Referring now to the embodiment of lnyinvention illustrated. inlFigs. -5 to $8, inclusive; the character'l'il designates, in general, aniniprove'd form of refleX'Klystron. The refeltencenumeral H designates the cathode mount, in, general, which is supported within an evacuated envelope 12* on insulator m which may be formedofporcelain or similarmaterial. :Sai'd plate vis-heldin lace by rods 65, the heads 6'! of which are desirably countersunk in a ring 68, which is .in turn secured, as by soldering or welding to a flanged annular member '69 carrying insulation?! Lwhich may be glass and provided with an. exhaust tube '52.

The insulat0ri'3 is'held in place bymeans of collar devices Hi which'are soldered or otherwise suitably secured in'placeon theupper or other ends of the rods 65. Saidrods 68 pass through hollow cylindricalspacing elements '10, theconstruction thereby'providingforholding the insulator 2.3 andxthe supporting ring element 68 in the proper assembled relation. Through this insulator also pass lead-"in 'conductors, those numbered 26 and at b'eing'from the cathode heater filament "Eli which maybe like -thefilament 2!? of the preceding embodiment and mounted in *asimilar manner above -a reflector plate 25 The other leads include-that-designated 38 to the cathode 2 9 which may be formed like the cathode--2il of the preceding embodiment, and thelead' ifi 'for the cathodeheatshield" 33* -whieh-c-arries a -grid'-4l'l and focusing ring i as in the preceding mbodiment.

All 'of the leads, that is,-those-numbered 26 27 "38% $2 and 45 those numbered 2b and 42 including in circuit a getter device M as in the preceding embodiment, finally pass to corresponding outer contact members 73 -which are,

in turn, held in o-uterinsulator disk l L-whi-ch tical withgthat described in: connection .yvithzthe t e d m ntam il ustrat d ainexplod dview in Fig. 4, so that further description here is unnecessary. However, instead of being enclosed in a part glass or vitreous envelope, the present cathode mount is enclosed in an all-metal envelope portion consisting of a hollow steel or other suitable metal cylinder or shell 11, provided with an outstanding lower or outer flange 18, to which the outstanding annular flange 19 of a supporting base member 8| for the flanged annular member 89 and suitably connected ring 68, is secured, which completes the lower sealed portion of the envelope.

The outer base portion of the envelope consists of a ring 82, annular in section, as illustrated, the outstanding flange portion 83 of which is secured to the flange 19 in any desired manner, as by means of welding or soldering. A desirable construction involves the simultaneous welding of all of the three flanges l8, l9 and 83 together. The Bakelite or other contact-holding insulator disk 14 is secured to the ring 82 in any desired manner, as by means of cement or tabs on the member 82 bent into notches in the disk 74.

The envelope portion l2 is completed by the flange element 54 at its upper end which, in turn, carries a plate and cylindrical flange member 55, with grids 56 and 51 The member W is united to a flexible wall portion 58 of a hollow generally cylindrical cavity resonator device 59. The up per wall SW of the cavity resonator 59 also carries a grid 62* as well as a top mounting ring 84 to which the metal tube can 85 is secured, as by copper brazing in a hydrogen furnace as indicated at 90. The tube can 85 is centrally apertured and connected to an eyelet 88, which may be formed of Kovar or other material which seals well to glass, as by copper brazing 81 in a hydrogen furnace, preferably at the same time as the connecting of the parts 84 and 85. The upper outer contact member 88, which may also be formed of Kovar or the like, carries the reflector 63 of nickel or the like, as by means of its desirably steel supporting rod 89 the outer or upper end of which is sealed thereto as by solder indicated at 91'. The contact 88 is secured to the eyelet 88 by means of a glass or vitreous sleeve 92.

Adjustment of the frequency of the electrical energy generated in the device, by varying the distance between the walls 8N and 58 is effected by flexing the latter. This is accomplished by the adjusting screws 93 (only one of which is illustrated) threaded into the top mounting ring 84, held in adjusted position by nuts 94, and with their lower ends socketed to receive the rounded studs 95 mounted in flange element 54, against the action of the tension coil springs 96, which act to pull the members 54 and 84 together.

From the foregoing disclosure, it will be seen that we have a hollow resonant micro-wavegenerator of the reflex Klystron type, as an improvement on that shown in Figs. 1 to 4, inclusive, whereby the upward or forward moving electrons from the cathode 29 are bunched in passing through the constriction between the grids and 62 giving up energy while passing back therethrough in bunches on the reflected or return path. The generated energy may be withdrawn along the coaxial line 64, as by using the loop device 85 In the former tube construction, generally represented, except as to the cathode mount, in Figs. 1, 2 and 3, the cathode mount is held on a relatively fragile glass stem, placed in a sealing fixture, and laboriously aligned so that when the fixture is held in a chuck and rotated, the focusing ring 49 will run true to within .001". It is then placed in a lathe and sealed to the cavity resonator or shell assembly, after the latter has been aligned in said lathe to approximately the same accuracy.

As can readily be seen, this is a slow process which requires very skillful operators. It may inadvertently result in poor alignment giving low output and loss of the tube.

The improved tube of the embodiment of Figs. 5 and 6, however, may be manufactured by first mounting the cathode assembly on the base memher 8!, to within an accuracy of approximately ,64" to ah", and then projection welding the outstanding flanges l8, l9 and 83, using a removable jig or plug 99 to align the focusing ring 49 and metal shell 11 during said welding operation, as illustrated in Fig. 7, thereby securing a very accurate alignment between said ring and shell. Welding may be facilitated by forming the flanges l8 and 83 with theannular corrugations I98 and W8.

In the tube illustrated in Figs. 1, 2 and 3, the reflector 69 has been welded to a Kovar lead 89 that had previously been beaded and a glass flare attached. In such a case it had to be aligned so that the axial and lateral eccentricity of the reflector cup rim was not greater than .001, when the lead on the opposite side of the flare is held in a chuck and rotated. This can only be obtained by bending the Kovar lead until the reflector cup has the desired alignment. At best, this is difficult, as the strained Kovar lead returns to an unstrained position during sealing, resulting in a distorted position of the reflector.

In accordance with the embodiment illustrated in Figs. 5 and 6, the reflector is sealed into the shell assembly in a manner similar to the handling of the cathode. The reflector-supporting parts, that is, the top mounting ring 84, the metal tube can 85, the Kovar eyelet 88, the contact 88, and the connecting glass part 92, are assembled in a lathe to within approximately the same accuracy as the cathode mount. The alignment of the reflector in the tube is probably the most critical point in the manufacture. After cleaning, the assembly is placed over the aligning jig or plug fall, as illustrated in Fig. 8. The reflector, attached to heavy steel lead 89 is placed over in nesting relation with the projection 98 of said aligning plug 91, as illustrated, and the reflector lead 89 brazed to the Kovar contact cup 88 where the former protrudes, as indicated at in Fig. 5.

From the foregoing disclosure, it will be seen that I have devised an improved cathode mount assembly which may be used in either the form of Klystron illustrated in Figs. 1, 2 and 3 or as illustrated in Figs. 5 and 6. I prefer the latter construction, whereby the following advantages may be obtained:

1. Standard receiving-type metal tube parts may be used, instead of special parts prepared for One tube, to eliminate a large quantity of glass, Kovar and other critical material.

2. The number of operations may be reduced and the assembly simplified.

3. The present eight-lead glass-dish stem, considered to be the weakest manufacturing point in the tube, has been eliminated.

at. The tube is not subjected to vibration troubles because of the greater rigidity with which the cathode and reflector are mounted.

5. Poisoning of the cathode and general contamination of the inside of the tube, due to sealing .withjfires, has been eliminated, :by substitutin brazing hydrogen atmosphere.

'6. Noticcably greater efflciencyandpcwer .out-

put-is obtained due to the more accurately aligned cathode and reflector.

.ailt-hough pr-ferre'd embodiments of my inven- 'tlQllnhflVB been disclosed, it will be understood that modiflcationemay be madeWithin-the spirit and scope of the, appended claims.

I claim: 1. Agenerator for electricity of ultra-high-freenemy-comprising an electron-emissive cathode mount, an envelope comprised in part of a cavity resonator arranged coaxial with said mount,-a reflector on the side of said resonator opposite with a peripheral flange telescoped with the upper end of said shield, a focusing ring fitting over the grid flange and secured to said shield, andleads connected to said electrodes for energizing said filament and impressing the desired potentials on said cathode, resonator, and reflector ,to-cause an electron beam to pass from said cathode to said reflector and be directed backthrough said cavity resonator.

2. A enerator for electricity of ultra-high frequency, QOmprising an electron-emissive cathode mount, an nvelope comprised in partof a cavity resonator arranged coaxial with said vmount, a reflector on the side of said resonator opposite to said mount, the latter comprising an insulator having an upper projection carrying an extension of reduced cross section, a cathode cup member telescoped with said reduced extension, a heater filament enclosed in said cup member and supported on said extension, leads to said cup member and filament, passing through said insulator,

a hollow cylindrical cathode shield telescoped with said upper projection, a grid provided with a peripheral flange telescoped with the upper end of said shield, a focusing ring fitting over the grid flange and secured to said shield, and leads connected to said electrodes for energizing said filament and impressing the desired potentials on said cathode, resonator, and reflector to cause an electron beam to pass from said cathode to said reflector and be directed back through said cavity resonator.

3. A generator for electricity of ultra-high frequency'comprising a cathode mount, an envelope comprising an insulator on which said cathode mount is fixed, a metal ring to which said insulator is connected, a hollow cylindrical metal portion surrounding said mount, insulator and ring, and provided with an outstanding end flange, a

metal end portion closing the flanged end or" said cylinder, said end portion having an outstanding flange connected to the outstanding flange on said cylindrical portion, the intermediate portion of said end member being apertured, and a flanged annular member connecting said ring and end member and carrying a central insulatr ing closure portion through which leads to said cathode mount extend.

4. A generator for electricity of ultra-high frequency comprising an electron-cmissive cathode mount, an envelope comprising a cavity reso natordevice forming part thereof, the remainder of said envelope comprising an insulator on which said cathode mount is fixed, a metal ring to which said insulator is connected, a hollow cylindrical metal portion surrounding ,said mount, .in-

sulatorand :Iing and provided .With an outstandingz'end flange, a flanged annular metalmember 'secured'to the ,unflanged end of said metal cylinder, means connecting said annular member to;said-resonator, a metal end portion having an outstandin flange connected to the outstanding flange. on said cylindrical :portion, the intermediate-portioncf said end member being apertured, a flanged annular member serving to connect said ring andend member and carrying a central insulating closure portion provided with an exhaust tube and through which leads to said cathode mount extend, and a base device comprising a flanged annular member carrying an insulating disk with outstanding contact devices to which said leads are ccnnected'and an outstandin peripheral flange secured to said outstanding flange on said end closuremember.

- An electrode and mount assembly for a discharge device comprising acup member carrying electron-emissive material, a, heater filament enclosed-in said cupmember, ahollow cylindrical cathode shield-enclosing said cup member, a :grid provided with a peripheral flange telescoped with the upper end of said shield, a focusing ring fittin over the grid ,flangeand secured to said shieldandleadsconnected to said electrodes for energizing said filament and impressing desired potentials. on said cup and shield.

.6. An electrode and mount assembly for an electron discharge device comprising an insulatorhaving a projection-carrying extension of reduced cross section, a cathode cup member telescoped with said reduced extension, a heater filament enclosed in saidcupmember and supported'on said extension, leads to said cup mem- :ber and filament passing throughsaid insulator, a hollow cylindrical cathode shield telescoped with said projection, a grid with a peripheral flange telescoped with the upper end of said shield, a focusing ring fitting over the grid flangegand secured to said shield, an'd leads connected to said electrodes for energizing said heater filament and impressing desired poten- :ti-alson said cathode and focusing ring.

'7. Themethod of makin an envelope for an electron-discharge device comprising connecting a cavity resonator device to one end of a hollow metalcylinder, closing the other end of said cylinder by'means of an annular flanged member carrying a cathode mount and insulator ,througlr vhichleads to said mount extend, connecting'said leads to outer contact devices em- ;bedded in an insulating disk carried by a base comprising a-flanged metal annular portion, and securing said base .over said annularmember.

8. {Ihe method 0: connecting parts of agen- .erator for electricity of ultra-high'frequency, includinga cathode mount assembly and a focusing ring,in a hollow cylindrical metal-envelope portion, comprising positioning said cathode mollntassembly on an annular metal base memberprovided with an outstanding flange, placing the hollow cylindrical .portion so that its :lower ,end rests on said base flange, fitting a centering 1jig, so that one portion is telescoped with the upper end ,;of said .hollow cylindrical *member. andanother portion with the focusing ring, and then uniting the outstanding flanges of said hollow cylindrical'rnember and cathode assembly; base portion.

9. Themet'hod of connecting-parts of a gen- --c .ator.torelectricity of ultra-high. frequency, in- ;Glud-ing a cathode ,mount assemblyand a focus- .s ing .rin ,.ri,ncahollow cylindrical flanged metal envelope portion, comprising positioning said cathode mount assembly on an annular metal base member provided with an outstanding flange, plac ng the hollow cylindrical portion with its flanged end resting on said base flange, fitting a centering plug member, so that one portion is telescoped with the upper of said hollow cylindrical member another portion with the focusing and then weldin together the outstanding of said hollow cylindrical member and cathode mount assembly base portion 10. The method of assembling a reflector cup and support rod with respect to a portion cat a metal enclosing envelope comprising placing a mounting ring, a metal tube can, and an associated eyelet in contact and brazing them together, connecting an outer contact member to said eyelet by means of a glass connecting part, placing the assembly over an aligning jig, with the mounting ring telescoped with a portion of said jig and the reflector cup telescoped With a concentric projection thereon and the support rod of said cup projecting through a central aperture in said outer contact member, and uniting the protruding end of said rod to the adjacent portion of said contact member.

11. A generator for electricity of ultra-high frequency comprising a cathode mount, and insulator on which said mount is fixed, a cup shaped vitreous envelope portion, lead-in conductors passing through said envelope portion and supporting said insulator, a hollow metal cylindrical portion with one end connected to the edge or" said vitreous envelope portion, and a cavity resonator connected to the other end of said metal cylindrical portion completing the envelope.

l2. method of making an electron discharge device comprising forming a hollow metal cylinder, forming a cavity resonator, forming a closure member comprising an annular flanged metal plate carrying a central glass portion, mounting contact members in said glass portion, supporting an insulator from said closure member by means of hollow cylindrical spacer elements disposed therebetween and connected thereto by rods passing therethrough, mounting a cathode and heating filament therefor on said insulator, connecting said filament to a pair of said contact members,

connecting said cavity resonator to one end of cylinder, placing said cathode and filament in said cylinder, and closing the other end of said cylinder means of said flanged metal plate.

13. The method of making an electron dis charge device comprising forming a hollow metal cylinder, forming a cavity resonator, forming a closure member for said cylinder, mounting contact members in and supporting an insulator from said closure member, mounting a cathode and heating filament therefor on said insulator, connecting said filament to a pair of said contact members, connecting said resonator to one end of said cylinder, and mounting said closure memher on the other end. of said cylinder in completing the envelope for said device.

14. lhe method of making an electron discharge device comprising forming a hollow metal cylinder, forming a cavity resonator, forming a cup-shaped vitreous envelope portion, mounting contact members in said cup-shaped portion, supporting an insulator on said contact members, mounting a cathode and heating filament on said insulator, connecting said filament to a pair of contact members, connecting said resonator to one end of said cylinder, and closing the other end of said cylinder by means of said cup-shaped portion.

JOHN M. CARTER.

Ei-FEREIICES CITED following references are of record in the of this patent:

UNITED STATES PATENTS

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