US2518472A - Electron gun - Google Patents

Electron gun Download PDF

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Publication number
US2518472A
US2518472A US74283A US7428349A US2518472A US 2518472 A US2518472 A US 2518472A US 74283 A US74283 A US 74283A US 7428349 A US7428349 A US 7428349A US 2518472 A US2518472 A US 2518472A
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US
United States
Prior art keywords
emitting
cathode
emitting part
electron gun
electrode
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US74283A
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English (en)
Inventor
Heil Oskar
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Individual
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Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to US74283A priority Critical patent/US2518472A/en
Priority to NL151078A priority patent/NL85535C/xx
Priority to DEH1286A priority patent/DE831856C/de
Priority to AT172298D priority patent/AT172298B/de
Priority to CH282861D priority patent/CH282861A/de
Priority to FR1009449D priority patent/FR1009449A/fr
Application granted granted Critical
Publication of US2518472A publication Critical patent/US2518472A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J21/00—Vacuum tubes
    • H01J21/02—Tubes with a single discharge path
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J21/00—Vacuum tubes
    • H01J21/02—Tubes with a single discharge path
    • H01J21/06—Tubes with a single discharge path having electrostatic control means only
    • H01J21/10—Tubes with a single discharge path having electrostatic control means only with one or more immovable internal control electrodes, e.g. triode, pentode, octode
    • H01J21/14—Tubes with means for concentrating the electron stream, e.g. beam tetrode
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J3/00—Details of electron-optical or ion-optical arrangements or of ion traps common to two or more basic types of discharge tubes or lamps
    • H01J3/02—Electron guns
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J3/00—Details of electron-optical or ion-optical arrangements or of ion traps common to two or more basic types of discharge tubes or lamps
    • H01J3/02—Electron guns
    • H01J3/026—Eliminating deleterious effects due to thermal effects, electric or magnetic field
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2893/00—Discharge tubes and lamps
    • H01J2893/0029—Electron beam tubes

Definitions

  • This invention relates to apparatus for the production of an electron beam.
  • the gun may be used wherever a well defined high intensity beam of electrons is desired, several examples of which will be given later.
  • the use of the gun in a novel power amplifier forms the subject matter. of my application Serial No. 74,282 filedFebruary 3, 1949.
  • FIG. 1 is a cross-sectional view of the electron un and Figs. 2 and 3 show possible methods of supporting the cathode of the electron gun.
  • the electron gun consists of two specially shaped electrodes, namely, a cathode with emitting and non-emitting parts and an additional electrode.
  • the configurations and relative positions of the cathode and additional electrode are responsible for the desirable characteristics cf the gun, and this information is therefore given in detail in Fig. l.
  • the dimensions in this figure are relative only.
  • the absolute size of the Whole arrangement can be changed without disturbing the value of the current in the beam, which-obeys the 3/2 power law, or. the ratio between the area of the emitting surface of the cathode and the crossesectional area of the beam, which is of -the order of 230.
  • the current density in the beam is decreased as the size of the system is increased.
  • a practical size of the gun may be obtained by letting the dimensional figures in Fig. 1 represent millimeters.
  • the emitting surface of the cathode is designated l and is a hollow surface the curvature of which is lowest at the center and increases toward the border. More precisely the surface shown is that of an ellipsoid of rotation in which the ratio of the major axis of the rotated ellipse to the minor axis thereof is 1.3:1. As-shown this surface has a depth of 6.15 and a maximum'diameter of 18.6,.these figures being relative .only's-as already pointed out. The surface the positive electrode 4.
  • the boundary of the electron stream is shown by the dotted lines in Fig. 1.
  • the beam leaves the gun along parallel lines and is of high intensity, the crosssectional area thereof being approximately /230 of the area of emitting surface i. (not shown) potential of 1000 volts the current in the beam is milliamperes.
  • the above described electron gun has a number of uses as, for example, in Klystrons, travelling wave tubes and other tubes for the product-ion or amplification of short waves.
  • the advantage here as compared with known arrangements is in the high current density and high quality of the beam with parallel electron travel and uniform intensity over the cross-section.
  • Another application of the electron gun is the high temperature treatment of surfaces of solid bodies.
  • a solid body brought into the focal point of the electron gun can be heated in a very short time second) to temperatures of several thousand degrees.
  • a very thin layer of about 0.01 millimeter is heated and then cools very quickly due to the small heat content and the high conduction into the solid body.
  • This temperature treatment may be used to obtain an extremely fine crystalline structure at the surface of a material by melting a thin layer of the material at the surface.
  • This process may alsobe used for coating a material with a substance having a higher melting point than the ground material as, for instance, steel on aluminum or tungsten on copper.
  • the coating material can be brought onto the surface by galvanizing, by evaporation, by cathodesputtering or by spraying and is then melted by the electron beam in which case alloying or chemical reaction with the ground material is avoided by the quickness of the action.
  • the rapid heating action of the high intensity electron beam may also be made use of in alloying materials which could not be alloyed in a process requiring considerable time due to the volatility of one of the components.
  • FIG. 2 A simple way of providing thermal insulation between the emitting and non-emitting portions of the cathode and at the same time having a very small'distance between the hot and cold parts is shown in Fig. 2. It uses the thermal expansion of'the emitting part to produce a distance between the two parts which in the cold state touch each other.
  • the emitting portion I of the oathode is backed by a suitable electrical heating element and cover therefor, all forming a unitary structure 20. This structure is supported on the extended cold part 2-3 by inclined legs h) and If and two similar legs at right angles thereto only leg 2! of which is shown.
  • the legs are welded to extend electrode 2-3 and to the unitary emitting electrode structure 23 at points 22, 23, 2t and a fourth point not shown, With'the emitting electrode 20 resting on and touching the non-emitting electrode 2-3.
  • the emitting electrode structure 25 is heated, however, the distances between the fix points 22 and 23 and between the fixed points 2 3 and an opposite point not shown increases'slightly due to thermal expansion of the structure 29 and this 4 causes the hot portion of the cathode to lift off the cold part thus preventing direct heat conduction to cold part 2-3.
  • An electron gun comprising a cathode having a hollow emitting surface the curvature of which increases. from the center to the edge thereof, an additional electrode positioned opposite said emitting surface and having a passageway therethrough converging in a direction away from said surface, and means for maintaining said additional electrode at a fixed potential relative to said cathode, whereby electrons released by the emitting surface of said cathode pass through said passageway to form a beam having a cross-sectional area much smaller than the area of said emitting surface.
  • An electron gun comprising a cathode made up of electron emitting and non-emitting parts, said emitting part having a hollow emitting surface the curvature of which increases from the center to the edge thereof, said non-emitting part having an edge conforming to the edge of said hollow emitting surface and positioned adjacent thereto whereby said non-emitting part forms a closure for said emitting surface, an opening in said non-emitting part opposite said emitting surface, an additional electrode positioned within said opening and having a passageway therethrough, said passageway having its longitudinal axis of symmetry perpendicular to said emitting surface and having a convergence in a direction away from said emitting surface, and means for maintaining the emitting and non-emitting parts of said cathode at the same electrical potential and at a lower potential than that of said additional electrode, whereby electrons emitted from said hollow emitting surface pass through said passageway to form a beam having a cross-sectional area much smaller than the area of said emitting surface.
  • An electron gun comprising a cathode having a hollow emitting surface conforming to the surface of an ellipsoid of rotation and having an axis of rotational symmetry perpendicular to said surface at the center thereof, an additional electrode positioned opposite the open end of said hollow emitting surface and having a passageway rotationally symmetrical about said axis, said passageway being convergent in the direction away from said cathode and having a toroidal surface at the cathode end and a conical surface at the opposite end, said two surfaces being joined longitudinally intermediate the ends of said passageway, and means for maintaining said additional electrode at a fixed potential relative to said cathode, whereby electrons released from said emitting surface of said cathode pass through said passageway to form a beam of high intensity and small cross-sectional area as compared with the area of said emitting surface.
  • An electron gun comprising a cathode having an emitting part and a non-emitting part, said emitting part having a hollow emitting surface conforming to the surface of an ellipsoid of rotation and having an axis of rotational symmetry perpendicular to said surface at the center thereof, said non-emitting part having means forming a truncated conical non-emitting surface the axis of which coincides with said axis of rotational symmetry, said truncated conical sur- I face having its maximum circumference equal to centered on said axis of rotational symmetry, an
  • additional electrode having rotational symmetry about said axis and having a maximum external diameter smaller than the diameter of said opening, said electrode extending through said plane surface forming means from a point inside the cathode space to a point outside the cathode space, a convergent passageway through said additional electrode having rotational symmetry about said axis and having its larger opening facing said hollow emitting surface, the surface of said passageway being toroidal at the larger end and conical at the smaller end with the two surfaces joining tangentially at a point intermediate the ends, and means maintaining the emitting and non-emitting parts of said cathode at a selected fixed electrical potential relative to said additional electrode, whereby electrons released by said emitting surface pass through said passageway to form an electron beam of much smaller cross-sectional area than the area of said emitting surface.
  • Apparatus as claimed in claim 4 in which the emitting part of said cathode is supported on an extension of the non-emitting part thereof by a plurality of pairs of oppositely disposed legs symmetrically arranged about said axis and inclined thereto, said legs being rigidly fixed at the ends to said emitting part and said extension and having such length that said emitting part when cold is in contact with said non-emitting part, whereby thermal expansion of said emitting part when heated spreads the distances between the fix points of said legs on said emitting part thus producing a slight separation of said emitting and non-emitting parts and preventing conduction of heat therebetween.

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  • Electron Sources, Ion Sources (AREA)
US74283A 1949-02-03 1949-02-03 Electron gun Expired - Lifetime US2518472A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
US74283A US2518472A (en) 1949-02-03 1949-02-03 Electron gun
NL151078A NL85535C (sv) 1949-02-03 1950-01-17
DEH1286A DE831856C (de) 1949-02-03 1950-01-18 Elektronenkanone
AT172298D AT172298B (de) 1949-02-03 1950-01-20 Elektronenkanone
CH282861D CH282861A (de) 1949-02-03 1950-01-20 Einrichtung zur Erzeugung eines Elektronenstrahls.
FR1009449D FR1009449A (fr) 1949-02-03 1950-01-24 Canon à électrons et amplificateur électronique utilisant ce canon

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US74283A US2518472A (en) 1949-02-03 1949-02-03 Electron gun

Publications (1)

Publication Number Publication Date
US2518472A true US2518472A (en) 1950-08-15

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Family Applications (1)

Application Number Title Priority Date Filing Date
US74283A Expired - Lifetime US2518472A (en) 1949-02-03 1949-02-03 Electron gun

Country Status (6)

Country Link
US (1) US2518472A (sv)
AT (1) AT172298B (sv)
CH (1) CH282861A (sv)
DE (1) DE831856C (sv)
FR (1) FR1009449A (sv)
NL (1) NL85535C (sv)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3192425A (en) * 1961-03-06 1965-06-29 Zenith Radio Corp X-ray tube with adjustable electron beam cross-section
US3916202A (en) * 1974-05-03 1975-10-28 Gen Electric Lens-grid system for electron tubes

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE977183C (de) * 1953-05-01 1965-05-20 Telefunken Patent Elektrostatisch stark buendelndes Elektronenstrahlerzeugungssystem
DE975107C (de) * 1953-05-15 1961-08-17 Telefunken Patent Elektrostatische Linse mit rotationssymmetrischen Elektroden, insbesondere fuer Kathodenstrahlroehren
US3139552A (en) * 1960-03-07 1964-06-30 Hughes Aircraft Co Charged particle gun with nonspherical emissive surface

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1979392A (en) * 1931-05-04 1934-11-06 Siemens Ag Cathode ray tube
US2079163A (en) * 1932-05-31 1937-05-04 Farnsworth Television Inc Electron gun
US2100701A (en) * 1932-10-21 1937-11-30 Schlesinger Kurt Braun tube
US2146365A (en) * 1934-12-13 1939-02-07 John C Batchelor Electron emitter
US2174853A (en) * 1937-08-26 1939-10-03 Hygrade Sylvania Corp Electron gun structure and method of assembly thereof
US2284389A (en) * 1940-08-31 1942-05-26 Gen Electric Rectifying system
US2303166A (en) * 1941-01-21 1942-11-24 Bell Telephone Labor Inc Electron discharge device
US2308800A (en) * 1941-02-15 1943-01-19 Bell Telephone Labor Inc Electron discharge device

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1979392A (en) * 1931-05-04 1934-11-06 Siemens Ag Cathode ray tube
US2079163A (en) * 1932-05-31 1937-05-04 Farnsworth Television Inc Electron gun
US2100701A (en) * 1932-10-21 1937-11-30 Schlesinger Kurt Braun tube
US2146365A (en) * 1934-12-13 1939-02-07 John C Batchelor Electron emitter
US2174853A (en) * 1937-08-26 1939-10-03 Hygrade Sylvania Corp Electron gun structure and method of assembly thereof
US2284389A (en) * 1940-08-31 1942-05-26 Gen Electric Rectifying system
US2303166A (en) * 1941-01-21 1942-11-24 Bell Telephone Labor Inc Electron discharge device
US2308800A (en) * 1941-02-15 1943-01-19 Bell Telephone Labor Inc Electron discharge device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3192425A (en) * 1961-03-06 1965-06-29 Zenith Radio Corp X-ray tube with adjustable electron beam cross-section
US3916202A (en) * 1974-05-03 1975-10-28 Gen Electric Lens-grid system for electron tubes

Also Published As

Publication number Publication date
NL85535C (sv) 1957-07-15
AT172298B (de) 1952-08-25
DE831856C (de) 1952-02-18
FR1009449A (fr) 1952-05-29
CH282861A (de) 1952-05-15

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