US2388289A - Electron discharge device - Google Patents

Description

6, 1945. v. RONCI ELECTRON DISCHARGE DEVICE Nov.

Filed Aug. 8, 1941 3;: low \m...

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IN VE N 7' 0/? w L. RONC/ FIG.

A 7 TORNEY Patented Nov. 6, 1945 UNITED STATES EN CE.

ELECTRON DISCHARGE DEVICE;

Victor'L. Ronci, Brooklyn, N. Y-, assign'or'to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application August 8, 1941, Serial No. 405,938 7 Claims. (01. 250-275) This invention relates to electron discharge devices and more particularly to such devices operable at ultra-high frequencies and having cavity resonators associated with electrodes thereof.

In one class of electron discharge devices commonly designated as velocity variation devices, the input or output systems or both include cavity resonators associated with gaps within an enclosing vessel and defined by a pair of electrodes. The enclosing vessel is usually of a vitreous material and parts at least thereof are within the high frequency fields between the electrodes or gaps and the resonators so that these parts absorb energy from the fields and thereby provide an energy or power loss resulting in a decrease in the operating efiiciency of the device. Also, the resonant frequency of such resonators is dependent upon the form and dimensions thereof so that when a change in the operating frequency 1 is desired replacement of the resonator often is required or the introduction ofv some form of tuning means is necessitated.

One object of this invention is, to reduce losses due to insulating or vitreous material within the high frequency fields of cavity resonators: asso-- ciated with ultra-high frequency electron dis charge devices and thereby to increase theoperating efilciencyof such devices. a

Another object of this invention is to'facilitate y the tuning of cavity resonators associated with electron discharge devices.

In one illustrative embodiment of this invention, an electron discharge device of the velocity variation type comprises an enclosing vessel hav ing walls of vitreous or insulating material, an electron gun for producing an electron beam, pairs of electrodes defining gaps traversed by the electron beam, and cavity resonators associated with the gap defining electrodes and in energy transferring relation therewith.

In accordance with one feature of this invention, the cavity resonators constitute wall portions; of the enclosing vessel, are conductively associated with the gap defining electrodes, and together with the it electrodes define a continuous electrical enclosure the interior of which is sub stantially freeof vitreous or insulating material. In accordance with another feature ofthis invention, the cavity resonators are provided-with flexibleportions allowing alteration of the form oftheresonators and, hence, adjustment of the resonant irequencythereof. q l V 4 The invention and the above-notedand other features thereofwill Joe-understood more clearly and fully from the following detailed description with reference to the accompan ing drawing, in which:'

Fig. 1 is an elevational view partly in section of a velocity variation electron discharge device illustrative of one embodiment of this invention;

Fig. 2 is an enlarged detail view in section showing the construction of one of the cavity resonators included in the device illustrated in Fig. 1 and showing also the association of the resonator with two gap defining electrodes in the device; I y 7 Fig. 3 is a detail view section of a modification of the construction illustrated in Figs. 1 and 2 particularly suitable forassociation with a coaxial transmission line;

Figs. 4A to 4F are detail sectional views of several cavity resonator structures made in accordance with this invention: and

Fig. 5 is a plan view of one of the grid electrodes and a portion of the cavity resonator associated therewith. I l

Referring now to the drawing, the electron discharge device shown Fig. 1 comprises an enclosing vessel having three cylindrical vitreous portions Illa, lllb and [0c andhous'i'ng an electron gunl I, which may be of thecons'triiction disclosed in Patent 2,303,166 granted November 24, 1942, to J oseph P. Laico, for projecting an electron beam axially of the enclosingve'sseL-a collector elec trode l2, and a cylindrical drift space electrode I3. Mounted between the electron l1 and electrode l3 are a pair of grid electrodes l4 and I5 defining an input gap [6 and having associated therewith a toroidal cavity resonator designated generally as IT. A second pair of grid electrodes 3 and I9 are mounted between the drift space and collector electrodes, define an output gap 20 and have associated therewith a toroidal cavity resonator designated generally at 2| similar in construction to the resonator l1.

During operation ofthe device, the electron stream produced by the electron gun H crosses the gap 16 and, when the resonator I1 is energi zed, undergoes a velocityvariation. The stream then flows through the drift space and is thus converted into a density varied beam which traverses the gap 20 and delivers energy to the resonator 2|. Energy may be supplied to the resonator ll and taken from the resonator 2| in known ways.

As shown more clearly in Fig. 2, the cavity resonator 11 includes two similar, dished annular members each of which comprises an inne -annular portion 22d or 221) to which the grids I4 or I5 are secured and an outer annular portion 2317. or 23b. The portions 22 and 23 may be of copper or other metal copper coated or plated and corresponding portions may be brazed or welded together. The outer portions 23 a and 23b may be welded together adjacent their peripheries. The joints, whether welded, brazed or otherwise formed, are made in such manner that the parts joined are sealed hermetically to one another.

In the fabrication of the device, the annular portions 22a and 23a are joined hermetically and the annuli 22b and 231) are similarly joined. The

which are illustrated in Figs. 4A to 4F, inclusive.

-In the construction illustrated in Fig. 4A, the

sufiiciently thin to allow tuning of the resonator annulus 22a is then hermetically sealed to and-- between the vitreous cylinder la and a glass ring 24 and the annulus 22b is sealed. similarly to the.

vitreous cylinder [b and a glass "ring 25. The

grids I 4 and I are then secured suitably to the 1 respective annuli 22a and 22b and the outer annuli 23a and 23b are subsequently joined adjacent their peripheries.

nuli 22a or 221) have substantially the same, coieflicients of expansion, the glass rings 24 orj25 may beomitted. 1 L j The grids l4 and I5 may be composed of parallel wires and in the assembly of the: device or the manner described above, it will be appreciated that, if desired, the wires of the two grids may be aligned withrfacility.

The annular portions 23a and 232) are made of suflicient thickness to prevent contact between the two grids l4 and I5 and yet sufficientlythin so that they may be flexed by the application of pressure thereto to alter the form of the resonator and thereby tune it to a desired frequency. The flexing action is restricted to theportions 23a and 23b due to the sealing of the portions 22a and 22b adjacent their. peripheries so that when the resonator is tuned the grids I}! and I5 are maintained in parallel relation. g

It will be noted that the resonator and grids constitute an electrically continuous enclosure so that very close and eflicient coupling between the electron stream'and the resonator is realized. The interior of this enclosure is devoid.

of insulating materialexcept forthe glass rings 24 and 25, which are of small volume, so that losses due to absorptioniof'energy from'the high frequency fields are very smalland a correspond: ingly. high operating efiiciency is, obtained. r H

The pressure for flexing the portions'23a and 23b may be applied through any suitableinstrumentalities as, for example, through a pair of annular membersfthreaded'to one another and each bearing against one of the annular portions 23a and 23b, or througha pair'of clamping members engaging these annular portions and adjustably spaced by a suitable micrometer drive. 7

.In the construction illustrated in Fig. 3, the cavity resonator 2! is provided with a. plurality If the glass and metal employed for the cylinders Illa or [0b and the an- 7 by the application of pressure between the portions of these members outside of the cylinders,

as by application of pressure between the flanges .32. r

The construction illustrated in Fig. 4B is similar to that shown in Fig. 4A except that the metallic members are of such form that the inof small apertures through each of which a wire pick-up conductor 26 extends, the several conductorsv 23 being mounted on a flanged metallic support2l extending between and sealed hermetically to cylindrical'vitreous portions I 00 and llld of the enclosing vessel. Coaxial conductors 28 and 29 are connected to theresonator ZlQand support 21 as shown and couplethe resonator and pick-up conductors to a suitable load or circuit. A similar coaxial line may be associated in the same manner with the resonator l1 associated with the input gap l6. The cavity resonators l1 and 2l may.bejo f a variety of forms. and constructiona.Qther than those'shown in Figs. 1, 2 and 3,'a ;nurnber of termediate portion of the resonator is rectangularin radial section. I

In the construction shown-in Fig. 40, the metallic members forming the cavity resonator are provided with flexible corrugated portions 33 which facilitate tuning of the resonator by flexure of wall portions thereof.

In the construction shown in Fig. 4D, the intermediate portion of the resonator is substantially entirely outside of the vitreous cylinders I00, and lilb and the inner flanges 3| are her- Although a number of specific embodimentsof this invention have been shown and described, it will be understood that they are but illustrative and that various modifications may be made therein without departing from thesco'pe and spirit of this'invention' as defined in theapp'end'edclaims ""IIHV j i' Whatis claimedis': f I T f- J i .1. An electron discharge "device compr is'ing means for producing an 'ele'ctron'stream, an electrode, a pair of electrodemembers'between 'said means and said electrode defininga' gapjmeans defining a cavity resonator including a pairfof annular metallic members in juxtaposition and hermetically joined at their peripneries; each of said annular members having an inner substantially rigid portion mounting one of saidelectrode members and having also anlouter' flexible portion, and an enclosing yesse 'ho smgsaiq nrst means, electrode members and electrodeand constituted in part by spaced parts of thefle'xible portions of said annular metalli members? c 2. Anelectron discharge'device comprising 'an enclosing vessel includin'g'a pair oiifvitreouscylindrical members in spaced end-'to-endrel-ationja pair of juxtaposed annular metallic members defining a cavity resonator andhavingjparts constitutingf a portion" 6f th enclosirig vessel, said metallic members bein'g"joinedfhrmetically at their peripheries and hermetically sealed to ljuxtaposed ends or" said cylindricalffnembergthe space bounded by said resonatonbing substantially free of insulating intrane -spam l taposed electrodesjwithin saidvessel, defining agap n a d r s a r eea hsarn ri ib i said annular members, an electron gun within said vessel and opposite one of said electrodes, and a collector electrode opposite the other of said members.

3. An electron discharge device in accordance with claim 2 wherein said annular metallic members include juxtaposed wall portions outside of said cylindrical members, deformable by pressure to tune the cavity resonator.

4. An electron discharge device comprising means defining a metallic toroidal cavity resonator the space within which is substantially free of insulating material, said means including a pair of juxtaposed annular metallic members each having inner and outer flanges and intermediate dished portions, the outer flanges of said members being joined hermetically, an electrode mounted on the inner flange of one of said members, a second electrode mounted on the inner flangeof the other of said metallic members, an electron gun opposite one of said electrodes, a collector electrode opposite the other of said electrodes, and an enclosing vessel including a pair of aligned, cylindrical, insulating wall portions each joined hermetically to one of said annular metallic members.

5. An electron discharge device comprising a pair of annular metallic members defining a cavity resonator and having inner portions and flexible outer portions, the outer portions being joined hermetically adjacent their peripheries, a pair of electrodes secured to the inner portions of said metallic members, an enclosing vessel constituted in part by portions of said metallic members and having aligned cylindrical vitreous portions hermetically sealed to the inner portions of said metallic members, and a pair of electrodes within said vessel and in cooperative relation with said first electrodes. I

6. An electron discharge devicecomprising an enclosing vessel including a pair of vitreous cylindrical members in spaced end-to-end relation, means defining a toroidal cavity resonator, said means including a pair of inner annular metallic members hermetically sealed to the juxtaposed ends of said cyindrical members and including also a pair of outer annular metallic members hermetically joined at their outer edges and each joined hermetically to a corresponding one of said inner metallic members, a pair of substantially parallel electrodes within said vessel and each secured to a corresponding one of said inner annular members, and electrode means within said vessel in cooperative relation with said electrodes. p

7. An electron discharge device comprising an enclosing vessel including a pair of vitreous cylindrical members in spaced end-to-end relation, means defining a toroidal cavity resonator including a pair of annular metallic members between. and hermetically sealed to the juxtaposed ends of said vitreous members, said metallic members being joined hermetically adjacent their peripheries, a pair of electrodes mounted by said metallic members, within said vessel and defining a gap, means for projecting an electron stream across said gap, a plurality of pick-up conductors within said vessel and extending within said resonator, a metallic support mounting said conductors, hermetically sealed to and projecting from said enclosing vessel, and coaxial conductors external to said vessel connected one to said support and the other to said resonator.

VICTOR L. RONCI.

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