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US2523776A - Electrion discharge device with hollow resonator - Google Patents

Electrion discharge device with hollow resonator Download PDF

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Publication number
US2523776A
US2523776A US641590A US64159046A US2523776A US 2523776 A US2523776 A US 2523776A US 641590 A US641590 A US 641590A US 64159046 A US64159046 A US 64159046A US 2523776 A US2523776 A US 2523776A
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United States
Prior art keywords
resonator
potential
reflecting electrode
electrode
reflecting
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Expired - Lifetime
Application number
US641590A
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English (en)
Inventor
Pearce Albert Frederick
Barford Norman Charles
Mayo Bernard Joseph
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Electric & Mustical Ind Ltd
Electric & Mustical Industries Ltd
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Electric & Mustical Ind Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J25/00—Transit-time tubes, e.g. klystrons, travelling-wave tubes, magnetrons
    • H01J25/02—Tubes with electron stream modulated in velocity or density in a modulator zone and thereafter giving up energy in an inducing zone, the zones being associated with one or more resonators
    • H01J25/22—Reflex klystrons, i.e. tubes having one or more resonators, with a single reflection of the electron stream, and in which the stream is modulated mainly by velocity in the modulator zone
    • H01J25/24—Reflex klystrons, i.e. tubes having one or more resonators, with a single reflection of the electron stream, and in which the stream is modulated mainly by velocity in the modulator zone in which the electron stream is in the axis of the resonator or resonators and is pencil-like before reflection

Definitions

  • This invention relates to electron discharge devices with hollow resonators and has exclusive reference to the type of device comprising an electron beam source, a resonator and a reflecting electrode system adapted to reflect the electron beam, after the latter has passed through the resonator, back into the resonator so that the device can function as a generator of oscillations.
  • the hollow resonator which may be of suitable toroidal form, or of other suitable forms as have heretofore been proposed, is usually maintained at about 1000 to 2000 volts positive with respect to the cathode.
  • the electrons are reflected due to the field set up by the reflecting electrode system which usually comprises a single reflecting electrode maintained at a negative potential of some hundred volts or more with respect to the cathode.
  • the beam is reflected back through the apertures in the resonator without impinging on the reflecting electrode and in the space between the resonator and the reflecting electrode the velocity modulation which is imparted to the beam on passing through the resonator, becomes converted into charge density modulation.
  • this type of device there are, in general, two conditions to be satisfied.
  • the time taken for the electrons to pass from the centre of the gap between the apertures in the resonator to the reflecting region and back to the resonator must be such that the charge density modulated beam returns through the resonator in the correct phase.
  • This transit time is usually arranged to be equal to multiplied by the periodic time of the oscillations where n is any integer which in practice is generally less than six.
  • the electric field in the reflecting region must be soshaped that the majority of the electrons are, in fact, reflected back through the resonator, otherwise inefliciency results.
  • the efliciency in these circumstances therefore depends critically upon the actual potentials applied to the resonator and the reflecting electrode, with. the result that if a particular resonator potential is selected and the reflecting electrode potential is adjusted to afford the optimum eiflciency for such resonator potential then any slight changes from such potentials will cause a decrease intthe optimum efliciency. It is generally found that if one of these potentials is increased the optimum value of the other potential decreases, i. e., the potential should be changed in opposite senses.
  • an electron discharge device of the type referred wherein the reflecting electrode system is such that the potential gradient set up between the resonator and the reflecting electrode system when appropriate operating potentials are applied to the resonator and the reflecting electrode system is small at the zero equipotential surface.
  • a device according to the invention is used as a generator of oscillations the device can be used in a circuit without expensive voltage stabilising devices, since the potentials applied to the resonator and the reflecting electrode system can both vary in the same sense within a larger range than heretofore without causing a substantial change in the efficiency of the device. In such a case it will be understood that any fortuitous change of the supply potentials which might occur in practice would affect both voltages simultaneously and would not therefore cause the frequency of the generated oscillations to be substantially changed. Where, however, a device according to the invention is employed in an automatic frequency control circuit then the potential applied either to the resonator or to the reflecting electrode system must be changed over a fairly wide range in order to force the oscillator to change its frequency of oscillation.
  • the required potential gradient can be obtained mainly by employing an elongated reflecting electrode system of suitable shape.
  • Various examples of electrode systems suitable for use in the invention will be described more fully hereinafter.
  • WhiCh- Figure l is a curve illustrating the potential distribution between a resonator and a reflecting electrode system in a device according to the invention
  • Figure 2 illustrates a series of curves indicating the relationship between the potentials applied to the resonator and to the reflecting electrode
  • Figure 3 is a diagrammatic view of a known form of electron discharge device of the type referred to, 7
  • FIGS 4, 5 and 6 illustrate electron discharge devices of the type referred to constructed in accordance with the invention
  • Figure '7 is a diagram of a superheterodyne receiver embodying an automatic frequency control circuit.
  • the two important results of the present invention arise by making the potential gradient small at the zero equi-potential surface.
  • zero equi-potential surface means an imaginary equi-potential surface in space which has a potential corresponding to the potential of the cathode.
  • the cathode is maintained, as is possible, at a negative potential of 1000 to 2000 volts and the resonator at zero potential, then the zero equi-potential surface will of course be that surface which has the potential of the cathode.
  • Figure 1 of the accompanying drawings illustrates the potential distribution set up along the axis of the device between the zero equi-potential surface and the centre of the gap in the resonator, the potential being plotted as ordinates and the distance between the centre of the gap in the resonator and the zero equi-potential surface as abscissae.
  • the centre of the gap is the point lying midway between those surfaces of the reso nator which define the gap.
  • the present invention resides in making the potential gradient at the zero equi-potential surface small.
  • the difference between the potential of the zero equi-potential surface and the potential averaged between the zero equi-potential surface and the centre of the resonator gap is not less than one-third of the total difference of potential between the zero equi-potential surface and the centre of the resonator gap.
  • the gradient is 0.4 to 0.3 of said averaged gradient and preferably said difference is larger than one-third.
  • curve a indicates the relation between a series of negative potentials applied to the reflecting electrode and a series of positive potentials applied to the resonator for affording optimum efficiency at a given frequency.
  • the curve a is typical of the known form of device shown in Figure 3 of the drawings in which the reference numeral 6 indicates a hollow resonator of toroidal form having the cross-section shown.
  • the cathode of the device is indicated by the ref erence numeral 1 and the reflecting electrode system comprises a single reflecting electrode of shallow dish-form indicated by the reference numeral 8.
  • the envelope I of the device is shown in Figure land is omitted in Figures 3, 5 and 6 for the sake of clarity.
  • the potential gradient at the zero equi-potentiaI surface in a device such as shown in Figure 3 would be substantially larger than 0.6 of the averaged gradient and it is found that by making the gradient less than 0.6 the operating potentials of the device can be changed over a wider range in the same sense without causing such a large change in optimum efficiency.
  • the reflecting electrode 8 of the device as shown in Figure 4 is in the form of an elongated hollow cylinder, that is to say, its axial length exceeds its diameter. It is considerably longer than the reflected electrode shown in Figure 3 and surrounds the beam for a considerable length.
  • the rear surface of the resonator G is preferably made substantially fiat in the vicinity of the electrode 8.
  • the curve I) of Figure 2 of the drawings indicates the relation ship between the resonator potential and the potential applied to the reflecting electrode of the device shown in Figure 4. It will be observed that this curve has substantially no slope and hence if the supply potentials should change in the same sense during operation the reduction in efliciency which would result will not be so large as the reduction which would result when employing a device as shown in Figure 3.
  • the device in Figure 4 provides some improvement compared with the'device in Figure 3, it is possible to obtain a further improve ment by employing an elongated reflecting electrode 8 of the form indicated in Figure 5 of the drawings, this electrode comprising a hollow frustum of an inverted cone, i. e., its apex is directed towards the rear surface of the resonator 6.
  • this electrode comprising a hollow frustum of an inverted cone, i. e., its apex is directed towards the rear surface of the resonator 6.
  • the diameter of the aperture at the apex of the reflecting electrode may be 3 the angle at the apex 110, and the length of the electrode along the axis of the beam may be 6 mms.
  • the diameter of the aperture in the surface of the resonator adjacent the reflecting electrode may be 1 mm.
  • figures can be regarded respectively as an infinite tube and as an infinite cone; consequently, the flat rear surface can be omitted if desired.
  • the intermediate frequency output from the mixer is amplified in an intermediate frequency amplifier 12 the output from the amplifier l2 being fed to a detector l3 and to a known form of discriminator circuit M which provides an output depending on the departure of the intermediate frequency from its assigned value.
  • the output from the discriminator circult I4 is fed to the local oscillator H and serves to control the frequency of the oscillations generated by said oscillator in such a manner that the intermediate frequency signals are mainr tained at the correct frequency.
  • the output from the detector i3 is fed to, a low frequency amplifier i5. 7
  • the. ratio of the diameter of the aperturev t in the flat rear surface of the resonator to the inner diameter of the tubular electrode 8 may vary from 111.5 to 1:4,
  • the diameter of the aperture may be 0.040" whilst the tubular electrode may have a length of 0.5 and a diameter of 0.160 and may be spaced from said surface of the resonator by a distance of 0.004".
  • the resonator may be maintained at a positive potential of 1600 volts with respect to the cathode of the device and the reflecting electrode at a negative potential of 180 volts.
  • Such a device provides a frequency change of 20-30 megacycles per second without a substantial reduction in output.
  • substantial reduction means a reduction'exceeding half the power available when the resonator and thereflecting electrode are at their optimum-potentials.
  • said ratio may be 1 :3, i. e., the diameter of the tubular electrode may be 0.120", the otherdimensions andthe operating potentials being the same as the example above referred to. In this case a. frequency change of 40 megacycles per second was obtained without a substantial reduction in output.
  • the latter may comprise, "in a further form of the invention, illustrated in Figure 6, a reflecting electrode proper l6, which may be of concave form, and a tubular electrode i1 interposed between the resonator and the reflecting electrode Iii, the tubular electrode in this case being maintained at a potential intermediate the potential of the resonator and the reflecting electrode it.
  • the distance between the centre of the gap in the resonator and the zero equi-potential surface should be large so that the zero equipotential surface is well removed from the gap.
  • the distance between the centre of the gap and the zero equi-potential surface may be 2.6 mms.
  • the potential applied to the reflecting electrode should be fairly low, a typical example being that stated above when the potential applied to the resonator is 1600 volts.
  • the voltage'applied to the reflecting electrode can be substantially higher.
  • the invention is also applicable to devices in which the beam is of non-circular form.
  • the beam is of ribbon-shape
  • the reflecting electrode system must be suitably shaped to deal with the ribbon-shaped beam.
  • a tubular electrode of circular form in cross-section instead of employing a tubular electrode of circular form in cross-section,
  • the reflecting electrode may be of elongated form in cross-section or may simply comprise a pair of fiat parallel plates.
  • the invention can also be applied to devices to which the beam is of annular form and passes through an annular gap ing the sections shown in Figure 4, or 6 about i an axis spaced from and parallel to the axis of the resonator shown in these figures.
  • the crosssectional shape of reflecting electrode systems in devices where the beams are of non-circular form in cross-section may be similar to the shape of the aperture in the near surface of the resonator and may have a similar ratio of dimensions as those described above.
  • the potential gradient referred to is the gradient along the axis of the electron beam where the latter is of circular form in cross-section since in this case the reflecting field is circularly symmetrical and in cases where the beam is of different form in cross-section the potential gradient is the gradient along a line which corresponds to the axis of the beam in the case where the latter is of circular form.
  • a device can be constructed according to the invention which is especially suitable for use in automatic frequency control circuits, it will be appreciated that such a device is also suitable for other purposes.
  • the device can be used as the modulator in a frequency-modulated transmitting system.
  • reflecting electrode system is relatively immaterial and'that other forms of reflecting systems might be employed whilst still maintaining the potential gradient small at the zero equipotential surface.
  • An electron discharge device having a single apertured cavity resonator, cathode means for directing a stream of electrons through said resonator, and a reflecting electrode structure ineluding an elongated hollow conducting electrode comprising a tubular member having a longitudinal axis disposed axially of the path of said electron stream and having an open end disposed adjacent the rear wall of said resonator to receive said electron stream whereby when appropriate operating potentials are applied to the resonator and the reflecting electrode structure the potential gradient set up between the resonator and reflecting electrode structure is small at the zero equipotential surface.
  • An electron discharge device having a single apertured cavity resonator, cathode means for directing a stream of electrons through said resonator, and a reflecting electrode structure including an elongated hollow conducting electrode comprising a hollow frustrum of an inverted cone disposed axially of the path of the electron stream and having an open end disposed adjacent the rear wall of said resonator to receive said electron stream, whereby when appropriate operating potentials are applied to the resonator and the reflecting electrode structure, the potential gradient set up between the resonator and the reflecting electrode structure is small at the zero equipotential surface.
  • An electron discharge device having a single apertured cavity resonator, cathode means for directing a stream of electrons through said resonator, and a reflecting electrode structure including an elongated hollow conducting electrode comprising an elongated hollow cylinder disposed axially of the path of said electron stream and having an open end disposed adjacent the rear wall of said resonator to receive said electron stream, whereby when appropriate operating potentials are applied to the resonator and the reflecting electrode structure, the potential gradient set up between the resonator and the reflecting electrode structure is small at the zero equipotential surface.
  • said reflecting electrode structure further includes a relatively fiat electrode disposed normal to the path of said electron;

Landscapes

  • Particle Accelerators (AREA)
  • Electron Sources, Ion Sources (AREA)
  • Stabilization Of Oscillater, Synchronisation, Frequency Synthesizers (AREA)
  • Microwave Tubes (AREA)
  • Lasers (AREA)
US641590A 1941-12-16 1946-01-16 Electrion discharge device with hollow resonator Expired - Lifetime US2523776A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB680/43A GB581895A (en) 1941-12-16 1941-12-16 Improvements in or relating to electron discharge devices employing hollow resonators

Publications (1)

Publication Number Publication Date
US2523776A true US2523776A (en) 1950-09-26

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Family Applications (1)

Application Number Title Priority Date Filing Date
US641590A Expired - Lifetime US2523776A (en) 1941-12-16 1946-01-16 Electrion discharge device with hollow resonator

Country Status (6)

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US (1) US2523776A (xx)
CH (1) CH263441A (xx)
DE (2) DE869243C (xx)
FR (1) FR918040A (xx)
GB (2) GB581895A (xx)
NL (1) NL78636C (xx)

Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2120974A (en) * 1936-04-03 1938-06-21 Rca Corp Automatic frequency control circuits
US2128232A (en) * 1934-02-23 1938-08-30 Meaf Mach En Apparaten Fab Nv Electron tube
DE665619C (de) * 1935-03-12 1938-09-29 Julius Pintsch Kom Ges Ultrakurzwellenroehre
US2170219A (en) * 1936-10-16 1939-08-22 Telefunken Gmbh Ultra high frequency oscillator
US2220840A (en) * 1937-07-14 1940-11-05 Gen Electric Velocity modulation device
US2250511A (en) * 1938-09-02 1941-07-29 Univ Leland Stanford Junior Oscillator stabilization system
US2259690A (en) * 1939-04-20 1941-10-21 Univ Leland Stanford Junior High frequency radio apparatus
US2287845A (en) * 1939-03-08 1942-06-30 Univ Leland Stanford Junior Thermionic vacuum tube and circuits
US2314794A (en) * 1940-06-25 1943-03-23 Rca Corp Microwave device
US2372213A (en) * 1940-05-11 1945-03-27 Int Standard Electric Corp Ultra-high-frequency tube
US2391016A (en) * 1941-10-31 1945-12-18 Sperry Gyroscope Co Inc High-frequency tube structure
US2406850A (en) * 1941-04-11 1946-09-03 Bell Telephone Labor Inc Electron discharge apparatus
US2417551A (en) * 1941-01-17 1947-03-18 Emi Ltd Electron discharge device and associated circuit

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2128232A (en) * 1934-02-23 1938-08-30 Meaf Mach En Apparaten Fab Nv Electron tube
DE665619C (de) * 1935-03-12 1938-09-29 Julius Pintsch Kom Ges Ultrakurzwellenroehre
US2120974A (en) * 1936-04-03 1938-06-21 Rca Corp Automatic frequency control circuits
US2170219A (en) * 1936-10-16 1939-08-22 Telefunken Gmbh Ultra high frequency oscillator
US2220840A (en) * 1937-07-14 1940-11-05 Gen Electric Velocity modulation device
US2250511A (en) * 1938-09-02 1941-07-29 Univ Leland Stanford Junior Oscillator stabilization system
US2287845A (en) * 1939-03-08 1942-06-30 Univ Leland Stanford Junior Thermionic vacuum tube and circuits
US2259690A (en) * 1939-04-20 1941-10-21 Univ Leland Stanford Junior High frequency radio apparatus
US2372213A (en) * 1940-05-11 1945-03-27 Int Standard Electric Corp Ultra-high-frequency tube
US2314794A (en) * 1940-06-25 1943-03-23 Rca Corp Microwave device
US2417551A (en) * 1941-01-17 1947-03-18 Emi Ltd Electron discharge device and associated circuit
US2406850A (en) * 1941-04-11 1946-09-03 Bell Telephone Labor Inc Electron discharge apparatus
US2391016A (en) * 1941-10-31 1945-12-18 Sperry Gyroscope Co Inc High-frequency tube structure

Also Published As

Publication number Publication date
CH263441A (de) 1949-08-31
DE869243C (de) 1953-03-02
DE840123C (de) 1952-05-29
GB581895A (en) 1946-10-29
NL78636C (xx) 1955-03-15
FR918040A (fr) 1947-01-28
GB577530A (en) 1946-05-22

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