US2474938A - Cavity resonator electron discharge device - Google Patents

Description

July 5, 1949.

E. J. GORN l 2,474,938

CAVITY RESONATOR ELECTRON DISCHARGE DVIGE Filed Sept. 12, 1944 2 Sheets-Sheet 1 July 5, 1949. Y E. J. GoRN l 2,474,938

CAVITY RESONATOR ELECTRON DISCHARGE DEVICE Filed Sept. l2, 1944 2 Sheets-Sheet 2 Patented July 5, 1949 CAVITY RESONATOR ELECTRON DIS CHARGE DEVICE sElmerJ. Gorn, Newton, Mass., `assignorito RaytheonManufacturing Company, Newton, Mass., a corporation of Delaware Application September 12, 1944, Serial No. 553,763

7 Claims. (Cl.315-40) This invention relatesitoelectrondischarge devices ofthe type in whichiitis desired to impart high speeds ,to electrically charged particles for l.various purposespand:particularly to devices in which-it is desiredrto imparti-high speeds to elec- :trons and toderive'high voltages therefrom.

For many `purposes itsisdesirable to convert :relatively lowvoltagey alternating current or di- ,.rect current intoa high voltage direct current. Suchv conversion 'has .heretofore involved the .use of expensive equipment.

It is vamong-the. objects gof .thepresent invention =to provide a novel means'andz method for convertling relatively low voltagecurrents into high voltagecurrents withoutaresortng-to expensive and cumbersome apparatus.

The aboveand other objects of the invention :will be made fully `apparent to those skilled in fthe-'artrom Ia consideration'ofithe following de- :tailed description ltakenvin conjunction ,with Ithe Yaccompanying drawing in which:

Fig. 1 shows a section taken on the line X--X :of Fig. 2 through ahigh voltage generator ,con-

fstructed in Iaccordance "with .the invention;

Fig. Zshows a section takenfon the line Y-Y of- Fig. l;

Fig. 3;shows `the device inside elevation and f on a scale substantially reducedfrom that of lFigs.

`1 and 2;*and

fFig. `i shows a fragmentary section taken on vthe line Z-,Z ,of Fig. 1.

`Referring .to the drawing, reference numeral -I indicatesan ,envelope-,consisting of a'block vof .highly conductive material; such as vcopper,and

having .apair of substantiallycylindrical cham;.= l

bers 2 and f3 constituting :afgeneratingand a receiving chamber, respectively, and each `provid.- .ing Lthe vanode structure oof ,a Fmagnetron. The cylindrical chambers-.2 and13fhave internal shouldered portions `4 yand 5, respectively, intermedi- 4-ate the length thereof. -Centralbores `Ii and 1 extend axially through :the shouldered Yportions 4 and 5. The shouldered portions14 and 5 each Yhas an even number` of `bores 8 and .9,respectively,

Iextending-through the peripheral ,portions there- `ofand disposed symmetrically around-the bores -6 Aand .'I and connected:therewithybyfradial slots .I and lI. The structure thus providesa plurality of .radially :extendingarms YI2 and I3 .in the kcylindrical chambers .2 A,and 3, respectively. Cathode vstructures I4 Vand .I5 .are centrally mounted inthe vbores and 1. The lcathode .structures I 4 and 4I 5 comprise hollow cylindrical members I6 and I1 of conductive'materialhaving activatedouter surfaces and `internalfheat- 2 `ingvelements I8 and I9. The hollow cylindrical fmembers I6 and I1 extendfparallel with the inner faces of the anode arms I2 and I3 and are spacedthere'fromfby annular spaces k2l] and 2|. The I`cathode `structure I4 is supported in. spaced position relative tolthe-anode armsby conducting rods Z2-and V23 vextending axially from each -endof the-cathode structure'into the end portions of the cylindrical chamber 2. Both of the @conducting rods 22l and `423 are A*electrically connected to thefheater .I8.and..one of them is also connected to ithe Ahollow cylindrical .member IB tosupplyya negative potential thereto lwhile the other is insulated therefrom. The conducting frods 2:2 land 23 -aresecured as for example by welding, to .theLinner ends of lead-in vconducv.tors v24 'amil-.5. :The lead-'in conductor 24 exv.tendsthrough .a ,conductivepipe 26 hermetically ,sealed in the'wall of the envelope I and has its .outer endfsealed through a glass seal 21 sup- ;ported'at .thefouter .endrof the conductive pipe 26. The other. .lead-:in conductor 25 extends :through azsimilar .conductive pipe, not seen in .the `drawi1f1g,.at1the lower end of the cylindrical chamber 2. vThe cathode structure I5 is likewise v.supported 'by conducting rods '30 and 3| projecting.axially'therefrom which are connected to :the cathode structure in the same manner as 'previously `described .in'connection with the conducting rods y22 and.23, which conducting rods are likewise connected to and supported by leadin conductors32 and 33. The lead-in conductor .32 extends through a conductive pipe 26 hav- -in'g aglass seal 21' and the :lead-in conductor v433'extends through a similar mounting, `not seen in thedrawing, at the lower end of the cylin- :drical chamber 3.

The cylindrical `chambers A2 and 3 are spaced in :the rblock I .so -as =to provide a partition 34 therebetween. .The partition 34 hasan iris opening 35 therethrough connecting one of the bores -.8 ofthe chamber 2 with one of the bores 9 of .the chamber-3. End caps 36 and 31, hermetically sealed to the .block lI lin-closing relation to the ends of the cylindrical chambers 2 and 3, com- ,plete the enclosure of the evacuated space of `fthe device. - Bole pieces 38 and 39, adjacent the portion of the .endfcaps 36 vand `3l closing the chamber -2, providea magnetic eld extending longitudinally of 4this chamber, ,and pole pieces `All `and 4I-,.similarly .positioned relative to the chamber 3, ,provide a magnetic field extending ,longitudinally-of thefchamber 3. The polepieces .38 and ..39 maybevthe opposite poles of a per- .55 `.manentmagnetformed of a material having a high coercive force, such as suitable alloys known in the art. Preferably, however, in order to vary the magnetic field I provide a core 42 of highly permeable magnetic material connecting the pole pieces 38 and 39, which core has a winding 43 energized from a suitable source of direct current 44 controlled by a rheostat 45. Similarly, the pole pieces 4i] and 4I are connected by the core 46 having a winding 41 energized from a source 43 controlled by a rheostat 49.

The laments I8 and I9 are adapted to be supplied with heating current by means of a circuit including a transformer 50 having a primary winding 5I and a secondary winding 52. The opposite ends of the primary winding 5I are connected to a suitable source of alternating current, not shown. One end of the secondary winding 52 is connected by a wire 55 to the lead-in conductor 24 and by a wire 56 to the lead-in conductor 32. The opposite end of the secondary winding 52 is connected by a wire 51 to the leadin conductor 25 and is also connected by a wire 58 to the lead-in conductor 33.

It will be seen that by this circuit an alternating heating current is Continuously supplied through the heating elements I8 and I9. A biasing potential is applied between the anode arms I2-I3 and the cathode sleeves Iii-I1 from a transformer 53, the primary winding of which is connected to a suitable source of alternating current, not shown, and the secondary winding of which is connected at one end by way of a switch 54 to the envelope I. The opposite end of the secondary winding of the transformer 53 is connected to the lead lines 55 and 56 of cathode heater circuit. It will be seen that, during that half wave of the alternating current from transformer 53 when a positive potential is applied to the envelope I and hence to the anode arms I2 and I3, a negative potential will be applied to the hollow cylindrical members I6 and I1 which are directly connected to the uppermost of the lead-in conductors 24 and 32 and insulated from the lowermost of the lead-in conductors 24 and 32. Thus a potential difference is applied between each of the cathode sleeves I6, I1 and the adjacent end faces of the respective anode arms I2 and I3 during this half wave of the alternating current. During the opposite half wave, the potential between the arms and the sleeves is reversed and the device does not utilize this half wave.

Within the central bore 1 of the chamber 3 is a target 59. The target 59 is formed of a strip of conductive material extending longitudinally through substantially the entire length of said bore. The target is positioned to project from the inner end of one of the slots II into the annular space 2| between the cathode structure I5 and the inner end faces of the anode arms I3. The target 59 is supported in the desired position by a lead-in conductor 60, the inner end of which is welded or otherwise rigidly secured to the target at a point intermediate the ends thereof. The lead-in conductor SDI extends through one of the slots II and its corresponding bore 9 and outwardly through a. conductive pipe 6I hermetically sealed through the wall of the envelope I. The outer end of the lead-in conductor B0 is sealed through a glass seal 62 hermetically closing the outer end of the conductive pipe 6I. The conductor 60 may be connected to any suitable utilization device. In the instance shown, this utilization device is illustrated diagrammatically as an electric precipitator comprising an extension of the conductor 60 passing centrally through a conductive sleeve 63, which sleeve is grounded by a cone ductor 64.

In the operation of the device described in the foregoing, when the device is energized, the lefthand side thereof comprising the chamber 2 and its associated parts functions as a generator of ultra-high frequency oscillations in the manner of a megnetron.

It will be understood that in the operation of such magnetrons, capacitances exist between the cathode :member I6 and the adjacent end face of each of the anode arms I2. Capacitances also exist between the adjacent side faces of the anode arms I2 across the slots I0. The inner walls of the bores 8 constitute inductances. The anode is so designed and spaced relative to the cathode that the capacitances and the inductances described constitute circuits which are tuned. These circuits are resonant at a predetermined frequency depending upon the geometry of the tube, each bore 8 and its adjacent arms forming a circuit tuned to the frequency at which each of the other bores 8 and its adjacent arms oscillate. In other words each bore 8 and its associated slot constitute a resonant cavity. In such magnetrons the electrons emitted from the active surface of the cathode I6 move in orbital paths around the cathode in the annular space 20 and in so moving give up energy to the resonant circuits described during those periods when the polarity of the energizing circuits is in the proper direction, thereby maintaining or increasing the intensity of the oscillations in said resonant cavities.

Oscillations generated in the resonant cavities of the chamber 2 are fed into similar resonant cavities provided by the bores 9. of the chamber 3 by way of the iris opening 35. The cavities provided by the bores 9 are designed to oscillate at the same frequency as the cavities provided by the bores 8, and accordingly the oscillations fed into the resonant cavities of the chamber 3 from the resonant cavities of chamber 2 induce oscillations in the resonant cavities of the chamber 3. When the cavities are so oscillated, electrons emitted from the cathode sleeve I1 derive energy from the oscillations of the resonant cavities of the chamber 3 receiving an angular acceleration. The strength of the magnetic eld through the chamber 3 is adjusted by the rheostat 49 so that those electrons whose angular motion coincides with the phase of the oscillations are driven into the target 59, imparting a high negative voltage to it. The target being insulated from the other elements of the device, this voltage tends to build up to a value corresponding to that of the highest speed electrons. This voltage may be utilized for any suitable purpose such as the electrostatic precipitator shown o1' for X-ray tubes or other high voltage direct current devices.

While the device has been shown as comprising a single envelope having a pair of chambers interconnected, it will be apparent that these chambers may be provided in separate envelopes connected together by any suitable transmission line for transmitting the oscillations generating in one of the envelopes to the other. Such separation of the two sections of the device is advantageous where it is desired to apply a different biasing potential to one of the sections than to the other.

While there has been herein described a pre- .5 ferrcdlfembodiment of the invention, other. embodimentsi withintha scope`v off the appended claim-s will be apparentto. thoseI skilled inA the art fromffaf consideration of the1 embodiment shown andLA theteachingshereof. For example, it will be apparentV that the device-'may be energized byl-direct current rather thaniu alternating current astshownuand that when so. energized the device Willi` genera-te a high. voltage, continuousndirect current; rather. thananpulsating direct current. Also itUwi-lli be apparent. that. certain parts Ymay bei-duplicated.. Infsome. instances. a pluralitypf targets 59 spaced about thel annular chamber 2| may be utilized instead of the single target shown.

Whatis claimed is:

1. device for-imparting high velocitiesto electrically charged particles comprising an evacuated envelope containing a plurality of cavity resonators and a source of charged particles, means adjacent said envelope for creating a magnetic field directed transversely to the paths of said charged particles whereby the charged particles are given an orbital motion, means coupled to said cavity resonators to supply oscillations to said cavity resonators at the resonant frequency thereof, said cavity resonators being symmetrically spaced along the orbital paths of said electrons to produce a varying electrostatic field for accelerating said charged particles, and a target separate from said cavity resonators positioned in the path of said charged particles to intercept the same and provide a voltage corresponding to the velocity thereof.

2. A device for imparting high velocities to electrically charged particles comprising an evacuated envelope containing a plurality of cavity resonators and a source of electrons, means adjacent said envelope for creating a magnetic field directed transversely to the paths of said electrons whereby the electrons are given an orbital motion, means coupled to said cavity resonators to supply oscillations to said cavity resonators at the resonant frequency thereof, said cavity resonators being symmetrically spaced along the orbital paths of said electrons to produce a varying electrostatic field for accelerating said electrons, and a target separate from said cavity resonators positioned in the path of said electrons to intercept the same and provide a voltage corresponding to the velocity thereof,

3. A device for generating a high voltage comprising an envelope having an evacuated space, a source of electrons in said space, means adjacent said envelope for creating a magnetic field through which said electrons pass whereby said electrons move through said space in orbital paths, means in said space for lsubjecting said electrons to a varying electrostatic field to give said electrons a plurality of accelerations thereby imparting a high velocity thereto, and a target positioned in the path of said electrons, said target being electrically insulated from the other parts of said device whereby electrons are accumulated upon said target and impart a negative voltage thereto.

4. A device for imparting high velocities to electrons comprising a sealed envelope containing a pair of chambers providing a generating chamber and a receiving chamber, electrode elements providing cavity resonators within the evacuated space of each of said chambers, said elements including a cathode and an anode in each of said chambers, means adjacent said generating chamber for establishing a magnetic field therethrough in: a direction,- transverse to the path; between the'y cathode and anode therein wherebyelectrons emitted." by,4 said last-named cathode are causedtto follow-orbital paths. and generate.: ult-ra high.k frequency oscillations., in said generati-ng.chamber,l andfmeans .intermediate said generating andz. receiving. chambers. to. transmit said ultra. high frequency oscillations from said generating chamber to said receiving chamber to induce oscillationsfin the cavity resonators of Said ,receiving chamber.

5. A device for imparting high. velocities to electrons comprising a sealed envelope containing a pair of chambers-providinga generating chamber andra receiving chamber, electrode elements providing .cavity resonators. within the evacuated space of each of said chambers, said elements including a cathode and an anode in each of said chambers, means adjacent said generating chamber for establishing a magnetic field therethrough in a direction transverse to the path between the cathode and anode therein whereby electrons emitted by said last-named cathode are caused to follow orbital paths and generate ultra high frequency oscillations in said generating chamber, a partition between said chambers, said partition having an opening therethrough connecting a cavity resonator of said generating chamber to a cavity resonator of said receiving chamber to transmit said ultr-a high frequency oscillations from said generating chamber to said receiving chamber to induce oscillations in the cavity resonators of said receiving chamber.

6. A device for imparting high velocities to electrons comprising a sealed envelope containing a pair of chambers providing a generating chamber and a receiving chamber, electrode elements providing cavity resonators within the evacuated space of each of said chambers, said elements including a cathode and an anode in each of said chambers, means adjacent said generating chamber for establishing a magnetic field therethrough in a direction transverse to the path between the cathode and anode therein whereby electrons emitted by said last-named cathode are caused to follow orbital paths and generate ultra high frequency oscillations in said generating chamber, means intermediate said generating and receiving chambers to transmit -said ultra high frequency oscillations from said generating chamber to said receiving chamber to induce oscillations in the cavity resonators -of said receiving chamber whereby the electrons emitted from the cathode of said receiving chamber are accelerated in an oscillating electrostatic field, and a target positioned in the path of said accelerated electrons.

7. A device for imparting high velocities to electrons, a sealed envelope containing a pair of chambers providing a generating chamber and a receiving chamber, electrode elements providing cavity resonators within the evacuated space of each of said chambers, ysaid elements including a cathode and an anode in each of said chambers, means adjacent said envelope providing a magnetic field through said generating chamber transverse to the path of electrons emitted from the cathode thereof and coacting with the electrostatic eld of said resonant circuits to generate ultra high frequency oscillations in said generating chamber, means intermediate said generating and receiving chambers to transmit said ultra high frequency oscillations from said generating chamber to said receiving chamber to induce oscillations in the cavity resonators of said receiv 7 ing chamber, means adjacent said envelope pro# vlding a magnetic eld through said receiving chamber whereby electrons emitted from the cathode of said receiving chamber move in orbital paths and are accelerated in an oscillating electrostatic field, and a target positioned in the path of said accelerating electrons.

ELMEIR J. GORN.

REFERENCES CITED UNITED STATES PATENTS Name Date Lawrence Feb. 20, 1934 Number Number 15 Number Name Date Zworykin Nov. 26, 1935 Samuel Dec. 8, 1936 Prinz et al June 22, 1937 Clavier et al Feb. 18, 1941 Blewett et al June 24, 1941 Smith July 7, 1942 Wolff Sept. 8, 1942 Litton Dec. 22, 1942 Spencer Sept. 24, 1946 Hansell Dec, 17, 1946 Hartman Jan. 14, 1947 FOREIGN PATENTS Country Date Switzerland Oct. 16, 1941 PHY THOMAS F. MUR

Assistant Gommssioner of Pate/nts.

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