US2936396A - Low noise electron gun - Google Patents

Low noise electron gun Download PDF

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Publication number
US2936396A
US2936396A US707719A US70771958A US2936396A US 2936396 A US2936396 A US 2936396A US 707719 A US707719 A US 707719A US 70771958 A US70771958 A US 70771958A US 2936396 A US2936396 A US 2936396A
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cathode
electrode
electron
electrons
emissive
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US707719A
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English (en)
Inventor
Malcolm R Currie
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Raytheon Co
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Hughes Aircraft Co
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Priority to NL234902D priority Critical patent/NL234902A/xx
Application filed by Hughes Aircraft Co filed Critical Hughes Aircraft Co
Priority to US707719A priority patent/US2936396A/en
Priority to GB40592/58A priority patent/GB854943A/en
Priority to BE574155A priority patent/BE574155A/fr
Priority to FR783025A priority patent/FR1218086A/fr
Priority to CH6807659A priority patent/CH365148A/de
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Publication of US2936396A publication Critical patent/US2936396A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J23/00—Details of transit-time tubes of the types covered by group H01J25/00
    • H01J23/02—Electrodes; Magnetic control means; Screens
    • H01J23/06—Electron or ion guns
    • H01J23/075—Magnetron injection guns

Definitions

  • This invention relates to electron beam tubes and more particularly to devices. y. Y h,
  • backWard-wave tubes and kly'strons is proportional to the average forward rvelocity component of the electrons at noise ratio at -the input of theldevice "divided by the 1 signal-tonoise ratio at the output.
  • Low noise electronA guns have heretofore usuallycon-'- sisted essentially ofV a diodelregion','that is", Van emitting cathode and accelerating anode,follow ed either by a series of accelerating anodes or a series of driftv tubes v.operated at different potentials.
  • the pur-y pose of the region beyond the .first anode is to minimize and de amplify the noise inthe beam.'
  • this is accomplished as gradually as .possible bya change in potential as a function of distance from the cathode.
  • a prime object of the present invention is to-provide an exceedingly low noise electron gun.' ,q I
  • VAnother object. is to providega Ylow noise'electron gun for use in abeam type amplifier device havinga noise figure'considerably below what has been considered to be ledr to the prediction of a generally accepted minimum the theoretical minimum.
  • vIt is another object to provide a low noise electron gun inI which the deviationA between rootmjean-square quantity of the forward velocity and averageforward velocity is' substantially decreased below what is possible to achieve present invention are achieved in a particular emb ment by providing an arrangementv including ⁇ a sideemissiv cathode immersed in a relatively strong'vinagnetit:V field j which is coincident with the desired path of vthe electroni beam.
  • the cathode has a frontend and aside eniissivel region lying contiguously rearwardly therefrom.
  • a potential proboard-shapingv electrode having .an inclined surface toward the emitting region or segmentof the cathode and diverging away fromthe path'at a predetermined angle. tained at a direct current potential which is more positive with respect to the cathode than is the accelerating electrode.
  • This arrangement of electrodesv and relative potentials produces a potential field having a gradient near the edge of the emitting region and having a pronounced radial component tending to pull electrons toward the profile-shaping electrode.
  • the strong axial magnetic eld and the small forward electric gradi.- ent pulls a major portion of the emitting electrons toward the accelerating electrode by the influence of the crossed lield effects.
  • the electrons emitted from the emissive Vside of the cathode have a full Maxwellian distribution in the direction of the magnetic field ranging from minus infinity to plus infinity with the peak at zero velocity.
  • the average forward velocity component is-substantially zero and is thus indeed decreased from that which exists ⁇ in the conventional half-Maxwellian distribution. It remains, however, to also decrease the deviation between the root-mean-square quantity of the forward velocity and the average forward velocity.
  • Figure l is a schematic view partially in section of an electron beam device constructed in accordance with the present invention.
  • Fig. 2 is a perspective view of a generalized embodiment of the low noise electron gun of the present invention
  • Fig. 3 is aview of a sheet beam-forming electron gun' embodiment
  • Fig. 4 is a View of a generalized cylindrical embodiment of the ⁇ electron gun of the present invention.
  • Fig, 5 is a view, partially in section, of a modifiedl cylindrical version of the electron gun of the present invention.
  • Fig. 6 is a sectional view of a hollow cylindrical beamforming embodiment of the electron gun of the present invention.
  • Fig. 7 is a diagram showing in greater detail the geometrical relationships of certain features of the electron gun of the present invention.
  • Fig. S is a pictorial graph plotting relative currentl
  • This prole-shaping electrode is maiu- ⁇ density across the front end surface of a cathode of an electron gun of the present invention
  • Fig. 9 is a pictorial graph plotting relative electron current density across the front end surface of a cathode of a hollow electron beam gun of the present invention.
  • Fig. 10 is a sectional view of a modilied cylindrical version of the electron gun of the present invention.
  • Fig. 11 is a graph plotting the electron velocity distribution of a prior art electron gun.
  • Fig. 12 is a graph of the Maxwell-Boltzmann velocity distribution of electrons associated with the electron gun of the present invention.
  • Fig. 1 illustrates an embodiment of the present invention combining a low noise electron gun with a particular electron beam amplifying device, the particular example chosen being a backward-wave traveling-wave tube amplilier 13
  • a glass envelope 14 includes an enlarged diameter portion 16 at -its left-hand extremity connected to an elongated portion 18 having a lesser diameter. Sealed to the righthand extremity of the elongated portion 18 is a collector electrode 20. Disposed along substantially the length of the elongated portion 18 is a slow-wave structure 22 which is terminated on either end by a matching ferrule 24.
  • a coaxial transmission line 26 Coupled to the input or righthand end of slow-wave structure 22 is a coaxial transmission line 26, the inner connector 28 thereof having a helical extension V30 which is coiled about envelope 14 in a manner to provide a contrawound helical transducer for launching traveling waves onto slow-wave structure 22.
  • an output coaxial transmission line 32 is coupled to the output end of slow-wave structure 22 in a manner to couple slow-wave signals olf from slowwave structure 22 and transmit them to a utilization device, not shown.
  • an electron gun 34 Disposed within the enlarged portion of the envelope 14 is an electron gun 34 which comprises in this particular example a cylindrical cathode 36 having a substantially planar front end surface 38 at its righthand end and an axially short emissive ring segment 39 on the exterior Vcylindrical surface of the cathode 36 immediately to the rear of the front end surface 38.
  • Cathode 36 is heated in the conventional manner by a heating electrode 40.
  • a potential profile-shaping electrode 42 is disposed about the cathode 36 in a manner Vto substantialy surround the emissive ring segment 39 and to extend both fore and aft of the emissive segment.
  • the potential profileshaping electrode 42, along with other elements of the gun 34, may be supported by a setl of dielectric rods 44 which maintain axial alignment and mechanical rigidity.
  • the first accelerating electrode 46 is an annular member having an opening 48 o-f suiiicient diameter to permit passage of an electron stream emitted by the cathode 36.
  • a second and a third accelerating electrode 50 and 51 are also supported by the dielectric rods 44.
  • the cathode 36 ⁇ is maintained at a negative potential by a source of Vpotential 52, the negative terminal of which may be connected to the cathode 36.
  • the heating electrode 4t! is also connected to ⁇ the source 52.
  • rI ⁇ he lirst accelerating electrode 46 is maintained at a positive vpotential with respect to the cathode by a connection to an appropriate tap, las shown, to the source 52.
  • the profile-shaping electrode 42 is connected to the source 52 at a next more positive tap.
  • the second and third accelerating electrodes '5,5 'and sgi are maintained, respectively. next .more positive; by appropriate vtaps also tov the source 52.
  • TheslQwfL wavje xstrucnure 22 maybe maintained next more positi ve,' vas shown, by connecting it to ground potential .through anisolatingresistor 54. ⁇ l I @Surrounding substantially lthe entire llength 'of the traveling-wavev tube 12 is a focusingmagnet 56 which maygbe a solenoid as shown and which is energized Jby' the source ofpotential 58,.
  • V The velectrons are eventually intercepted by thecollector electrode which dissipates their kinetic energy 'and vcon-,- ducts themv to ground through al source'of potential-60.V
  • Thev sourcev 60 is connected with itsv positive terminalto the collector 20 so that secondarily, emitted electronsY will not drift backwardly into.the .interaction region ofthe slow-wave structure 22 Aand causeVY added shot noisei orV ⁇ otherdeleterious effects'.
  • the cathode62- isz'maintainedat areference potential of Yzero volts. .Atprobyte-shaping electrode, surface. 70 is disposed ⁇ transversely from: the path and extends axially both behind and in front Yof the emissive segment. 66.
  • the surface v70 is,inclined, in a.
  • aA sheet-beam forming electron gun in which a cathode 74 has a side emissive vsurface 476whicl1 is included withinl a short axial emissive segment 78 of the cathode 74, segmentv78 lying a'djacently rearwardv of the front end thereof.
  • a potentialprofile-shaping electrode 80 is disposed symmetrically aboveandjbelowwhe emissivesegment78 and has'inclined potential prole-shaping surfaces .82 whichareex-n posed vtoward the emissive segment78and. diverge along the path o-f the electron stream 84.
  • the surfaces 82 are contiguous to the cathode :74 andiextend hothfore and aft of theemissive segment78. 1 Disposed axially to the right, in Fig. 3, of profile-shaping electrode 80 is an ac- ⁇ next more. positive with respectto the cathode.
  • FIG. 3 the entire configuration of Fig. 3 is immersed in a strong axial magnetic field designatedy z Referring'tof Fig. .4, there is. shownV ar generalized cylindrical embodimentroffthe-low noise electron.gun of the ⁇ v presen@ invention.. :A cylindrical cathode, isi axially aligned with the Path-Ofrece@ strewn ⁇ 9.0 anais main: tained at, a .direct currentreferencepotential.V0 equal to.
  • the cathodev 88 has ats'ideemissive vsurface 92 adjacent'itsrighthandfextremity which is oriented sub stantially ⁇ in afplane perperidicularfto ⁇ thefy path of the.-
  • a potential profileshaping electrode ksur-V face 94 having thev form of a fru'st'oconical ysurface of revolution about the axisfof; the ⁇ stream v90.
  • the deter-Y mining planes of the conical frustum lie respectively fore andaft of and parallel4 tothe side emitting surface 92.
  • a cylindrical beam gunY which. includes 'al cylindrical cathode 98 having a side emissive ring surface 100 lying within an axially short side emissive segment 102.
  • a potential profile-shaping electrode 104 vis :dise posed perpendicularly tothe axis of the cathode 98 and has a coaxial frusto-conical aperture 106 disposed aboutV the cathode 98 and extending both forwardly and rearwardly of the side emissivesegment ⁇ 102.
  • conicalsurface of ⁇ aperture l106 is contiguous to, the 'side emissive segment 102 and ⁇ diverges in the"direction'fofA the'electron stream 107..
  • surfaces 108 'and 110 Disposed to the right of the profile-shaping electrode 104 is, an
  • accelerating electrode 112 which has va circular vaperture 114 concentric with and disposed contiguouslyabout Vthe
  • Fig. 6 represents an embodiment of a cylindrical Ybeam forming electronj gun which produces two concentric hollow electron streams116andf' 117.
  • An annular cathode 118 is maintained vat aidirectcurrent reference potential YY@V Aequal,102er@ volts and isi.
  • the prole-shaping electrode j120 has a circular aperture which comprises a frusto-conical surfaceA of revolution 126 disposed concentrically about-andmadially contiguous to thecathode 118.V
  • the profile-shapingY Y electrode portion 12,2 comprises anouter frusto-conicaL j surface of revolution which is concentricwith ,thezcathg ode 118 and, as previously mentioned, 'isvsubstantiallly vcoplanar with theremainder of profile-shapingA electrdderfr. f f: ⁇
  • The-frusto-concal surface of profile-shaping electrode 1 20 diverges at arpredetermined angle in the direction of the. electron streams 116 and 117; and the frustoconical surfaceof the inner electrode,12 2 converges at the same predetermined' angle alongthe direction of the electron stream.
  • a first accelerating electrode 128 Disposed, perpendicularly'to the electron stream-116 and spaced therealong to the right of the profile-shaping electrode'120 is a first accelerating electrode 128 which has an annular aperture 130 concentric with and adjacent radially to the electron stream 117.
  • a second accelerating electrode 132 Disposed further ⁇ yet along the path of the electron stream is a second accelerating electrode 132 which is similarly orientedand has similar geometry with respect to the accelerating electrode 128.
  • One or more additional accelerating electrodes may also be utilized here.
  • the cathode 134 is disposedl along the axis of the electron stream 136 and has a side emissive ring portion 138 which is substantially planar and lies substantially perpendicularly to the axis of theelectron stream 136.
  • the emissive ring 138 lies substantially immediately to the rear of the righthand end, as seen in the figure, of the cathode 134.
  • the cathode 134 has a diameter, or transverse dimension, D and is maintained at a direct current potential V equal to zero.
  • a potential profile-shaping electrode 140 is disposed about and lies between a transverse plane 142 which is aft of the emitting ring portion 138 by a distance a and a transverse plane 144 which is forward of the emitting ring portion 138 by a distance designated b.
  • the surface of the profile-shaping electrode exposed toward the emissive ring portion 138 is inclined at an angle IB from the axis of the cathode 134.
  • the edge of the proboard-shaping electrode 140, designated by the plane 142 is spaced from the cathode 134 by a distance designated e.
  • an accelerating electrode 146 Spaced forwardly from the plane 144 by a distance c is an accelerating electrode 146 which is disposed symmetrically above andbelow, or around, the electron stream 136 and is maintained at a direct current potential V1.
  • a potential profile-shaping electrode 140 is maintained at a direct current reference potential of V2.
  • Fig. 8 there is shown a pictorial graph of relative electron current density on the horizontal scale versus position across the electron stream 150 of a typical side emitting cathode 152 as shown by the curve 148.
  • the curve is seen to be at a maximum oli the edge of the cathode and decreases to a minimum in either direction from the positioning maximum.
  • Fig. 9 shows a pictorial plot similar to that of Fig. 8 in which a curve 154 plots relative electron current density horizontally versus radial position across the electron stream 156 of an annular beam forming cathode 158.
  • the profile-shaping electrodes are not shown in either of Figs.. A8 or 9, :but the -electron Vcurrent density plots shown exist by virtue of a potential profile-shaping electrode surface such as shown in the other figures which is symmetrically disposed about thev side emitting portions of the cathode schematically shown in Figs. 8 and 9, and by virtue of the unique potential distribution among the various electron gun electrodes.V
  • Fig. 9 it is seen that the electron current density is greatest just off the edges of the cathode 158 and decreases to' a minimum in either radial direction therefrom.
  • FIG. 10 there is shown an embodiment of the present invention utilizing a negative grid probe 160 coaxially disposed within a hollow side emissive cathode 162.
  • Emissive material 164 is disposed on the outer cylindrical surface of cathode 162 near the front end or righthand end, as seen in the figure.
  • a profileshaping electrode 166 is disposed about the emissive material 164 similarly to the manner depicted in the previous figures.
  • the grid probe 160 is maintained at a direct current potential which is negative with respect to that of the cathode 162, as indicated by the connection of a battery 168 connected with its negative terminal to the probe 160 and its positive terminal to the cathode 162.
  • the negative potential on the probe 160 aids in preventing the migration 'of the emissive material 164 from its position on the cylindrical surface of the cathode 162* to the front end, planar surface to thus preclude all but a substantially pure side emission from the cathode 162.
  • microwave energy is delivered to the traveling-wave tube 12 along rthe coaxial transmission line 26.
  • a traveling wave is launched upon slow-4 wave structure 22 and is caused to interact therealong in a well-known manner with an electron beam projected from the electron gun 34 along the helix 22.
  • the microwave energy in the form of the traveling-wave havingA experienced interaction with the electron stream normally in a manner to achieve amplification is then coupled of of the helix 22 by the helical transducer' at the lefthand end, in Fig. 1, of lthe traveling-wave tube 13 and transmitted via the transmission line 32 to a utilization device, not shown.
  • the cathode 36 is heated by current flowing through its heater coil causing thermal' emission of electrons from the side emissive area 39.
  • the surrounding profile-shaping electrode 42 being maintained at a positive potential tends to cause electrons to be pulled radially outwardly toward it.
  • ll is a plot of the conventional Maxwell-Boltzmann distribution Vof electrons emitted in the direction of the electron stream of a prior art electron gun.
  • the relative' amountof current in an infinitesimal increment of velocity is plotted on the ordinate, versus magnitude of electron velocity on the abscissa. It is seen that the average velocity lies well to the right of the origin and is desigf nated as V on the figure. It is also indicated on this figure that the deviation between the root-mean-square quantity of the velocity and the average velocity 17 is of a relatively large magnitude.
  • e Referring to ⁇ Fig. ,12, vun ⁇ the other hand, ⁇ there is resents thel average velocity i7.
  • the theoretical minimum noise figure is proportional .to the average' electron velocity, the deviation between root-mean-square ofthe forward velocities' of electrons traveling in the direction of the'beam and the average velocity in that'. direction and to the product of these two quantities.
  • ⁇ It is indicated on Fig. 12 that the deviation quantity represented by the spacing between and frompthe similar deviation shown in Fig. 11.
  • AIt may further beseen thatA electrons having a' l 'velocity algebraically less than a critical velocity v determinedby the magnitude ofthe forward directed electric eld of the first accelerating electrode will be lost from 'the beam because these electrons will spiralinto*A the cathode and be lost.
  • electrons having a velocity in the forward direction algebraically'greater than v' will be pulled forwardly by theelectric field of the Afirst accelerating electrode and form a part of the beam. All the electrons having velocities between v and zero will obviously, when thus reflected forwardly, have Videntical velocities in the vopposite dir ectionas by a con-f servative fieldv reflection.
  • the resultant beam then has the. velocity distribution indicated bythe dotted line 1618i' .ofjFig l2. It may now be seen that the average velocity fin ythe forward direction is ⁇ considerably lower than ⁇ vhaif-Maxwellianfvelocitydistribution results from the beam being 'emitted in thefdirection of the stream while in .f the present invention it is avoided by emitting the electrons, predominantly transversely to the direction of the electron stream.' YBy utilizing such side emission, it is -possibleto grasp a greater fraction of the total number of electrons at low velocities.
  • a low noise electron gun for providing an electron beam in a forward direction along a predetermined lineal path comprising: a side emissive cathode for emittingv electrons in substantially all outward velocities from said side emissive cathode; means yfor providing a ⁇ constraining magnetic ieldabout said cathode in said forward direction along said path; a profile-.shaping electrode disposed contiguously tosaid cathode at right an-;
  • profileshaping electrode having a surface inclined toward said cathode and toward saidv forward direction, said surface forming an acute angle therewith; an accelerating elecv trode disposed ,adjacent to said path and spaced from said profile-shapingelectrode, said cathode being ata reference potential of zero volts, said accelerating electrode being at a potential ⁇ positive with respect tofsaid cath,
  • said profile-shaping electrode being at af potential positive with respect to said accelerating electrode whereby electrons are emitted ifrom the side of said cathode ⁇ lying toward said profile-shaping electrode, thoseemib;
  • a low noise electron gun for projectinga' streantv I of electrons. in a forward ydirection lalong a rpredeterl mined path comprising: a side emissive cathode having an emissive surface lying within a longitudinally Vshort seg-- ment along s-aid path for emitting electrons having sub-V ⁇ stantially all outward velocities from the side of saidV emissive cathode; a Aprofile-shapingA electrode ydisposedl from said emissive segment transversely to said path and having a longitudinal length which is greater thanV the length of s-aid emissive segment and whichV extends both fore and-aft ofA said emissive segment, said profile-y shaping electrode having an inclined surfacerexposed 'to-j; ward said axial segment which forms an acute angle with" said forward direction; means for providing aconstrain'- ing magnetic field about said cathode parallel to said predetermined path,
  • a backward-wave amplifier comprising; an elongated envelope disposed about a longitudinal axis; a; slow-wave structure within said envelope, said slow-Wave structure having an emitter end and a collectoi""end;-;y and'electric elds'in a manner to choosean optimum -75collector meansdisposed -at .the collector endqof-L saldi:
  • an electron gun housing coupled to the emitter end of said envelope and defining an enclosure for an electron gun assembly; input and output radio frequency coupling means contiguously disposed about said envelope at different points therealong; magnet means for providing a strong axial constraining magnetic field throughout the length of said electron gun assembly; and an electron gun assembly mounted within said electron gun enclosure, said assembly including a cylindrical cathode mounted along the longitudinal axis of said amplifier, the axis of said cathode coinciding with the axis of said amplifier and the end of said cathode which is closest the collector end of said slow-wave structure lying in a plane transverse to said axes; an emissive surface ⁇ disposed in a ring on the outer surface of said cathode, the ring of emissive material lying substantially in a plane transverse to the axis of said cathode and spaced at a predetermined distance from said collector end of said cathode, the potential of said cathode being at a reference of zero volts
  • the inner surface of said first electrode extending froma point which is further from the collector end on one side of said ring of emissive material to a point which is nearer the collector end on the other side of said ring, said inner surface defining a frusto-conical surface of revolution which diverges in the direction toward the collector end and whose axis is coincident with the longitudinal axis of said amplifier, said prole-shaping electrode being maintained at a potential of approximately five volts with respect to said cathode; a rst, planar anode spaced along the path of the stream of electrons at a pre-selected distance from said ring of emissive material and substantially parallel to the plane thereof, said first anode including an internal aperture, the surfaces defining said aperture being adjacent to and concentric with the hollow stream of electrons, said first anode being maintained at a potential of substantially four volts with respect to said cathode, and a plurality of further accelerating anodes mounted in successive planes transverse to the
  • a low noise electron gun for producing a stream of electrons along a predetermined path comprising: means for providing a constraining magnetic field along said path; a side emissive cathode disposed at one end of said path; an accelerating electrode disposed along said path and spaced from said cathode; a profile shaping electrode disposed contiguous to and a beam from said cathode and having a surface inclined towards said cathode and said path at an angle with said path of 70 to 35 degrees and extending forwardly from said cathede .005 to .06@ inch, said cathode being maintained at a reference potential of zero volts, said accelerating electrode being maintained at a potential positive with respect to said cathode; said profile shaping electrode being maintained at a potential positive with respect to said accelerating electrode whereby electrons are emitted from the side of said side emissive cathode, those electrons emitted with a forward velocity component algebraically less than a predetermined magnitude being precluded from entering said stream While electrons
  • a low noise sheet-beam electron gun for projecting a stream of electrons along a predetermined axial path comprising: a rectangular side emissive cathode having a planar front end surface disposed transversely to said path and having an axially short emissive segment disposed rearwardly Qf said front end surface; a profile shaping electrode disposed substantially parallel to said planar front end surface and contiguously about said cathode and having an axialthickness which is greater than the axial length of said axially short emissive section, said profile shaping electrode having an inclined planar surface exposed toward said axial segment and toward the direction of said path; an accelerating electrode disposed substantially parallel to said profile shaping electrode contiguously to said path and axially spaced from said profile shaping electrode along said path; and means for providing a relatively strong axial magnetic field throughout at least the region defined by the rear of said profile shaping electrode and the front of said accelerating electrode, said cathode being maintained at a direct current reference potential of zero, said acceleratorating electrode being maintained
  • a low noise electron gun for projecting a stream of electrons along an axial path in a predetermined direction comprising: a cylindrical cathode having an end portion substantially perpendicular to said axial path and an axially short emissive segment on the cylindrical surface of said cathode rearwardly from said end portion of said cathode; a profile shaping electrode disposed concentrically about said emissive segment and extending fore and aft thereof along said path, said profile shaping electrode comprising a frusta-conical internal surface of revolution concentric about said axial path and being exposed toward said emitting segment and diverging toward said direction; an accelerating electrode comprising a transverse sheet having an aperture concentric with said path, disposed transversely thereto, and spaced from said profile shaping electrode along said path; and means for providing an axial constraining magnetic field through at least the region defined by the rear of said profile shaping electrode and the front of said accelerating electrode, said cathode being maintained at a direct current reference potential of zero, said accelerating electrode being maintained
  • a low noise electron gun for producing a hollow cylindrical stream of electrons along an axial path in a predetermined direction comprising: a profile shaping electrode having a frusto-conical internal surface of revolution concentric about said axial path and diverging in said direction at a predetermined angle, the conical frustum being limited by first and second planes perpendicular to said axial path, said profile shaping electrode further comprising a second conical surface lying substantially between said first and second planes radially within said frusto-conical surface and converging at said predetermined angle in said presdeterrnined direction, said frustoconical and said conical surfaces being spaced from each other by a predetermined annular spacing; a cylindrical annular side emitting cathode concentric about said axial path and having an axially short emissive segment comprising an emitting circle on the external surface of said cylindrical cathode and a concentric emitting circle on the inner surface of said cylindrical cathode, saidrcathode being disposed in
  • a low noise electron gun for providing a cylindrical beam of electrons along an axial path in a predetermined direction comprising: a cylindrical side emissive cathode member having a ring shaped emitting portion and a substantially planar end, said emitting ring portion lying on the surface of said cylindrical cathode contiguously rearwardly of said planar end; a profile shaping electrode concentric with said cathodedisposed betweenrst and second planes transverse to said axial path, said first plane lying aft of said emitting ring portion by .001 to .550 inches and said second plane lying forwardly of said ,emitting ring portion by .001 to .100 inch and having a frusto-conical internal surface of revolution disposed symmetrically about said axial path at an angle of ⁇ 40 to 50l degrees therewith and extending Vbetween said planes and having a minimum diameter at said first plane and the maximum diameter at said second plane thereby diverging along said axial path, the end of said frustoconical surface having

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US707719A 1958-01-08 1958-01-08 Low noise electron gun Expired - Lifetime US2936396A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
NL234902D NL234902A (de) 1958-01-08
US707719A US2936396A (en) 1958-01-08 1958-01-08 Low noise electron gun
GB40592/58A GB854943A (en) 1958-01-08 1958-12-16 Low noise electron gun
BE574155A BE574155A (fr) 1958-01-08 1958-12-23 Canon à électrons à souffle réduit
FR783025A FR1218086A (fr) 1958-01-08 1958-12-31 Canon électronique à faible niveau de bruits
CH6807659A CH365148A (de) 1958-01-08 1959-01-07 Rauscharme Elektronenkanone

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BE (1) BE574155A (de)
CH (1) CH365148A (de)
FR (1) FR1218086A (de)
GB (1) GB854943A (de)
NL (1) NL234902A (de)

Cited By (10)

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US2985789A (en) * 1960-02-17 1961-05-23 Bell Telephone Labor Inc Low-noise electron gun
US3226595A (en) * 1960-03-31 1965-12-28 Rca Corp Low noise electron gun
US3278791A (en) * 1960-10-14 1966-10-11 Csf Electron discharge device having a plurality of emissive surfaces
US3353058A (en) * 1963-08-16 1967-11-14 Int Standard Electric Corp Slow wave structure having oppositely curved conductors disposed about the beam and mounted transversely between opposite walls
US3381155A (en) * 1964-08-26 1968-04-30 Arnaud Jacques Electron guns having at least one emissive cathode surface and one nonemissive electrode adjacent said cathode surface
US3446778A (en) * 1964-08-04 1969-05-27 Goodyear Tire & Rubber Block copolyester containing crystallizable polymeric units and rubbery polyester units
US3506866A (en) * 1966-04-26 1970-04-14 Siemens Ag Hollow electron beam generator having cathode of rotational generation whose surface coincides with magnetic flux
FR2295555A1 (fr) * 1974-12-20 1976-07-16 Watkins Johnson Co Canon a electrons produisant un faisceau rectangulaire
US4091311A (en) * 1976-12-17 1978-05-23 United Technologies Corporation Modulatable, hollow beam electron gun
US4350926A (en) * 1980-07-28 1982-09-21 The United States Of America As Represented By The Secretary Of The Army Hollow beam electron source

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DE1230923B (de) * 1963-11-23 1966-12-22 Telefunken Patent Thermische Emissionskathode und Verfahren zu ihrer Herstellung
US5332945A (en) * 1992-05-11 1994-07-26 Litton Systems, Inc. Pierce gun with grading electrode
DE10213652B4 (de) * 2002-03-27 2008-02-21 Bruker Daltonik Gmbh Verfahren zur Bestrahlung von Ionen in einer Ionenzyklotronresonanz-Falle mit Elektronen und/oder Photonen

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US2632130A (en) * 1947-11-28 1953-03-17 Joseph F Hull High current density beam tube
US2652512A (en) * 1950-12-22 1953-09-15 Bell Telephone Labor Inc Electron gun
US2798183A (en) * 1954-11-29 1957-07-02 Hughes Aircraft Co Traveling-wave tube
US2801361A (en) * 1948-12-10 1957-07-30 Bell Telephone Labor Inc High frequency amplifier
US2811663A (en) * 1954-10-22 1957-10-29 Hughes Aircraft Co Traveling-wave tube
US2851630A (en) * 1955-04-13 1958-09-09 Hughes Aircraft Co High power traveling-wave tube
US2869019A (en) * 1955-07-07 1959-01-13 Hughes Aircraft Co Reflex space-harmonic oscillator

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2632130A (en) * 1947-11-28 1953-03-17 Joseph F Hull High current density beam tube
US2801361A (en) * 1948-12-10 1957-07-30 Bell Telephone Labor Inc High frequency amplifier
US2652512A (en) * 1950-12-22 1953-09-15 Bell Telephone Labor Inc Electron gun
US2811663A (en) * 1954-10-22 1957-10-29 Hughes Aircraft Co Traveling-wave tube
US2798183A (en) * 1954-11-29 1957-07-02 Hughes Aircraft Co Traveling-wave tube
US2851630A (en) * 1955-04-13 1958-09-09 Hughes Aircraft Co High power traveling-wave tube
US2869019A (en) * 1955-07-07 1959-01-13 Hughes Aircraft Co Reflex space-harmonic oscillator

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2985789A (en) * 1960-02-17 1961-05-23 Bell Telephone Labor Inc Low-noise electron gun
US3226595A (en) * 1960-03-31 1965-12-28 Rca Corp Low noise electron gun
US3278791A (en) * 1960-10-14 1966-10-11 Csf Electron discharge device having a plurality of emissive surfaces
US3353058A (en) * 1963-08-16 1967-11-14 Int Standard Electric Corp Slow wave structure having oppositely curved conductors disposed about the beam and mounted transversely between opposite walls
US3446778A (en) * 1964-08-04 1969-05-27 Goodyear Tire & Rubber Block copolyester containing crystallizable polymeric units and rubbery polyester units
US3381155A (en) * 1964-08-26 1968-04-30 Arnaud Jacques Electron guns having at least one emissive cathode surface and one nonemissive electrode adjacent said cathode surface
US3506866A (en) * 1966-04-26 1970-04-14 Siemens Ag Hollow electron beam generator having cathode of rotational generation whose surface coincides with magnetic flux
FR2295555A1 (fr) * 1974-12-20 1976-07-16 Watkins Johnson Co Canon a electrons produisant un faisceau rectangulaire
US4091311A (en) * 1976-12-17 1978-05-23 United Technologies Corporation Modulatable, hollow beam electron gun
US4350926A (en) * 1980-07-28 1982-09-21 The United States Of America As Represented By The Secretary Of The Army Hollow beam electron source

Also Published As

Publication number Publication date
CH365148A (de) 1962-10-31
FR1218086A (fr) 1960-05-09
GB854943A (en) 1960-11-23
BE574155A (fr) 1959-04-16
NL234902A (de)

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