US3474282A - Electron gun for electron tubes in cathode heater device - Google Patents

Electron gun for electron tubes in cathode heater device Download PDF

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Publication number
US3474282A
US3474282A US560423A US3474282DA US3474282A US 3474282 A US3474282 A US 3474282A US 560423 A US560423 A US 560423A US 3474282D A US3474282D A US 3474282DA US 3474282 A US3474282 A US 3474282A
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United States
Prior art keywords
cathode
electron
emission
heat
auxiliary
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Expired - Lifetime
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US560423A
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English (en)
Inventor
Helmut Katz
Paul Meyerer
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Siemens AG
Siemens Corp
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Siemens Corp
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    • 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
    • H01J3/024—Electron guns using thermionic emission of cathode heated by electron or ion bombardment or by irradiation by other energetic beams, e.g. by laser

Definitions

  • an additional foil cylinder of molybdenum mounted within the tantalum foil cylinder and formed with a plurality of apertures for focusing the electron beam from the auxiliary cathode and the emission from the auxiliary cathode impinging upon the main cathode to heat it by electron bombardment.
  • the invention is directed to a beam production system for electrical discharge vessels, in particular power tubes, in which system the cathode emitting the beam electrons (beam system cathode) simultaneously forms an operating electrode of an auxiliary electron discharge system, serving for heating by electron impact.
  • the cathode temperature must be increased to over 1100.
  • the customary method for heating a cathode utilizes a heater which, by passage of electrical current, produces the necessary heat. Certain requirements, however, must be made with respect to the heater. If it is located in the immediate proximity of the cathode surface, it should, if possible, not produce an alternating magnetic field and, thereby, a hum. The current conduction therefore should, it possible, be bifilar and the heat current intensity should appropriately be kept as low as possible.
  • the entire inner space of the cathode is filled with insulation material, i.e., the heater spirals are cemented into the heater space in order to direct the heat to the actual cathode by means of the heat conduction of the insulation material involved, even at relatively low heater temperature.
  • This type of heater construction has the advantage that it results in a relatively small heat loss.
  • a considerable space is required which corresponds to a cathode body of much larger dimensions than that actually required for the desired emission.
  • the heat to be produced therefore amounts to a multiple of the quantity of heat actually required for the emission, so that an unnecessarily high amount of heat is received by the initial electrodes.
  • the purpose of the invention to achieve, by special constructional features, a beam system cathode in which the size and thus the surface thereof is as small as possible and, at the same time, to simultaneously avoid the previously described disadvantages of the prior customary constructions of such systems, in order to keep the temperature of the standard beam-forming electrode, immediately surrounding the beam cathode, as cool as possible so that such electrode cannot cause any thermonic emission during operation, even if emission-promoting substances are vaporized thereon.
  • metal capillary cathode as used herein means an indirectly heated dispenser cathode in which an emission promoting substance such as barium, is contained in a supply chamber that is covered by a porous emission material carrier or in the pores of this carrier, i.e., a plate whose structure remains porous in operation, for example, a plate of refractory metal such as tungsten, in particular, a porous sintered tungsten, and the emission promoting substance liberated, i.e., in the supply chamber passing only by means of diffusion along the porous walls to the emission surface, so that it is uniformly distributed over that surface during operation.
  • an emission promoting substance such as barium
  • a storage cathode in particular an MK-cathode, with a frontal porous carrier disk for the emission material of large diameter is provided, which may be impregnated, and which closes a relatively shallow storage container of cylindrical shape, filled with a supply substance, the bottom of which container represents the actual electron impact plane of the operating electrode of an auxiliary electron discharge system, axially arranged at the adjacent side of said cathode, i.e., the opposite side thereof with respect to the direction of the cathode beam emission.
  • the beam emission cathode is constructed without a heater and consists, therefore, only of the carrier disk for the emission material, forming the emission surface, and the emission material supply container which is covered by such disk, said container to receive its required heat supply, as an operative electrode, by electron impact from an auxiliary discharge system. Because of this, the dimension of the actual cathode can be kept very small so that the heat produced closely adjacent to the heat-critical electrode can, as a result, likewise advantageously be kept to an especially small amount.
  • the required cathode, necessary for the auxiliary discharge is likewise constructed as a storage cathode, of generally much smaller construction, in particular as a metal capillary cathode, which also has a frontal emission material'carrier and for the heating of which an appropriate customary heater is provided.
  • this heater is located much further away from the heat-critical electrode involved, its heat effect thereon is negligible.
  • a tube-shaped accelerating anode for the auxiliary system provided with one or several diaphrgms is arranged coaxially in a heat protective shell, constructed as a tantalum foil cylinder, and serving as the support for the principal cathode.
  • At least one of these diaphragms is proprovided with getter metal, for example zirconium, and its opening is so proportioned that it receives sufiicient heating by impact from the auxiliary electron discharge.
  • getter metal for example zirconium
  • the auxiliary discharge takes place with relatively high current density, it has at the same time, at least partially, the function of an ionization zone so that, in connection with the aperture diaphragm, which is capable of gettering, an effective ion gettering pump is formed.
  • thermo-voltage which is produced, during operation, at the junction formed by the cathode carrier, consisting of molybdenum, and the tantalum foil cylinder, is conducted to the Wehnelt-electrode, directly or appropriately amplified, for control of the intensity of the discharge current, and thereby so controlling the emission temperature of the principal cathode that, for example, an automatically operating temperature regulation is obtained.
  • the heat-critical beam-forming electrode of the beam-production system is designated by the reference numeral 1, with the beam system cathode 2, 3
  • the cathode being constructed as a storage cathode, in particular as an MK-cathode, which is located in the diaphragm opening of said electrode.
  • the cathode consists of an emission material carrier disk 2, forming the emission surface, and a storage container 3, which is covered by said disk. It has no customary heater so that its cathode body, the storage container, may be constructed as a very flat cylinder. Because of this construction, its surface is kept very small so that at this point the heat transfer, important with respect to the beam-forming elecrode, is at a minimum.
  • the cathode carrier is supported by a beam protective shell or housing comprising a tantalum foil cylinder 4 which is attached to cathode body 3 directly below the emission material carrier disk 2 and may be surrounded by still another beam protection cylinder 11.
  • the heat supply is achieved by electron impact from an auxiliary electron discharge which is produced substantially within the beam-protection case 4 by means of a coaxially disposed auxiliary discharge system.
  • a tubular-shaped accelerating anode 5 provided with one or several diaphragms 6, 7,
  • auxiliary cathode 8 constructed as a storage cathode, in particular, as an MK-cathode, having a heater 9 and appropriate Wehnelt cylinder electrode 10.
  • an electron fiow initially takes place from the heated cathode 8, said flow being accelerated through the anode 5 with its diaphragms 6 and 7 towards the principal cathode 2, 3 and flowing with a relatively high discharge density.
  • the diaphragm opening is so selected that it is smaller than that of the entrance diaphragm whereby a heating, sutficient for the gettering process, takes place due to the electron impact occurring in a manner similar to that of an aperture diaphragm. It is included in the method according to the invention to direct and control the discharge in such a way, when placing the discharge vessel involved in operation, that a sufficient pump effect is obtained without a considerable heating of the beam cathode. Naturally, a pump effect providing a high, good vacuum can be obtained continuously during operation of such an emitting principal cathode by means of the ionization source so formed and the getter device.
  • thermoelectric junction is created so that the thermo-voltage, produced at this point during operation, may be utilized for regulation of the emission temperature.
  • those portions of the mentioned parts representing the actual metal conductors, that is, storage container 3 and screening cylinder 4 are at least to a sufiiciently cold spot, made of the same respective metals.
  • the thermo-voltage thus produced is, directly following appropriate amplification, conducted to the Wehnelt cylinder of the auxiliary discharge system, by means of which the emission temperature is determined, and thus automatically regulated through the discharge current intensity.
  • a beam producing system for an electron discharge device comprising, a storage metal capillary cathode having a storage container of cylindrical shape, a carrier disk mounted on one side of said storage container, a supply of emission substance in said storage container, an auxiliary electron discharge system mounted on the other side of said storage container and said auxiliary electron discharge system comprising a second storage container, a second carrier disk mounted on one side of said second storage container, and means for heating said second storage container to cause a beam of electrons to be discharged on to the other side of said first storage container.
  • a beam producing system comprising a first metal foil cylinder attached to said first storage container and forming the support therefor and extending toward the auxiliary electron discharge system.
  • a beam producing system comprising a second cylindrical foil mounted inside the first metal foil and formed with a plurality of apertured diaphragms for controlling the beam of the auxiliary electron discharge system.
  • a beam producing system according to claim 2 wherein said first metal foil cylinder is formed of tantalum.
  • a beam producing system comprising a cylindrical control electrode in the form of a Wehnelt cylinder mounted adjacent the auxiliary electron discharge system to control the temperature of the storage metal capillary cathode.
  • a beam producing system comprising a heat shield metal cylinder mounted about the first metal foil cylinder to improve the heat characteristics of said beam producing system.
  • a beam generating system for electric discharge vessels, particularly high frequency performance tu bes having a cathode emitting an electron beam which is heatable by direct electron impact, an auxiliary cathode mounted at a distance thereof from said cathode to provide for the necessary electron bombardment and the auxiliary cathode is mounted in the direction of the beam axis behind the cathode and designed as an indirectly heated storage cathode of the M-K-cathode type.

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  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Electron Sources, Ion Sources (AREA)
  • Microwave Tubes (AREA)
US560423A 1965-06-30 1966-06-27 Electron gun for electron tubes in cathode heater device Expired - Lifetime US3474282A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DES0097900 1965-06-30

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US3474282A true US3474282A (en) 1969-10-21

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US (1) US3474282A (enrdf_load_stackoverflow)
DE (1) DE1514490A1 (enrdf_load_stackoverflow)
GB (1) GB1103890A (enrdf_load_stackoverflow)
NL (1) NL6607158A (enrdf_load_stackoverflow)
SE (1) SE321743B (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0387145A1 (fr) * 1989-03-07 1990-09-12 Thomson Tubes Electroniques Générateur de faisceau d'électrons et dispositifs électroniques utilisant un tel générateur
US6034472A (en) * 1997-02-28 2000-03-07 Siemens Aktiengesellschaft Vacuum tube having a getter apparatus
US20150187541A1 (en) * 2013-12-30 2015-07-02 Mapper Lithography Ip B.V Cathode arrangement, electron gun, and lithography system comprising such electron gun

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2410822A (en) * 1942-01-03 1946-11-12 Sperry Gyroscope Co Inc High frequency electron discharge apparatus
US2509053A (en) * 1947-11-08 1950-05-23 Bell Telephone Labor Inc Space current device employing mutually bombarded electrodes
GB643655A (en) * 1946-09-03 1950-09-27 Amherst Felix Home Thomson Improvements in or relating to magnetron electron discharge devices
GB766064A (en) * 1953-03-30 1957-01-16 Nat Res Dev Improvements in electron discharge tubes
US3010046A (en) * 1952-02-26 1961-11-21 Westinghouse Electric Corp Cathode structure
US3131328A (en) * 1960-06-20 1964-04-28 Gen Dynamics Corp Dispenser cathode for cathode ray tube
US3132275A (en) * 1960-05-31 1964-05-05 Eitel Mccullough Inc Electron gun and cathode heater assembly therefor
US3215884A (en) * 1961-04-27 1965-11-02 Gen Electric Cathode support structure

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2410822A (en) * 1942-01-03 1946-11-12 Sperry Gyroscope Co Inc High frequency electron discharge apparatus
GB643655A (en) * 1946-09-03 1950-09-27 Amherst Felix Home Thomson Improvements in or relating to magnetron electron discharge devices
US2509053A (en) * 1947-11-08 1950-05-23 Bell Telephone Labor Inc Space current device employing mutually bombarded electrodes
US3010046A (en) * 1952-02-26 1961-11-21 Westinghouse Electric Corp Cathode structure
GB766064A (en) * 1953-03-30 1957-01-16 Nat Res Dev Improvements in electron discharge tubes
US3132275A (en) * 1960-05-31 1964-05-05 Eitel Mccullough Inc Electron gun and cathode heater assembly therefor
US3131328A (en) * 1960-06-20 1964-04-28 Gen Dynamics Corp Dispenser cathode for cathode ray tube
US3215884A (en) * 1961-04-27 1965-11-02 Gen Electric Cathode support structure

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0387145A1 (fr) * 1989-03-07 1990-09-12 Thomson Tubes Electroniques Générateur de faisceau d'électrons et dispositifs électroniques utilisant un tel générateur
FR2644286A1 (fr) * 1989-03-07 1990-09-14 Thomson Tubes Electroniques Generateur de faisceau d'electrons et dispositifs electroniques utilisant un tel generateur
US5045749A (en) * 1989-03-07 1991-09-03 Thomson Tubes Electroniques Electron beam generator and electronic devices using such a generator
US6034472A (en) * 1997-02-28 2000-03-07 Siemens Aktiengesellschaft Vacuum tube having a getter apparatus
US20150187541A1 (en) * 2013-12-30 2015-07-02 Mapper Lithography Ip B.V Cathode arrangement, electron gun, and lithography system comprising such electron gun
US9455112B2 (en) * 2013-12-30 2016-09-27 Mapper Lithography Ip B.V. Cathode arrangement, electron gun, and lithography system comprising such electron gun
US9466453B2 (en) 2013-12-30 2016-10-11 Mapper Lithography Ip B.V. Cathode arrangement, electron gun, and lithography system comprising such electron gun
US20160314935A1 (en) * 2013-12-30 2016-10-27 Mapper Lithography Ip B.V. Focusing electrode for cathode arrangement, electron gun, and lithography system comprising such electron gun
US10622188B2 (en) * 2013-12-30 2020-04-14 Asml Netherlands B.V. Focusing electrode for cathode arrangement, electron gun, and lithography system comprising such electron gun

Also Published As

Publication number Publication date
GB1103890A (en) 1968-02-21
SE321743B (enrdf_load_stackoverflow) 1970-03-16
NL6607158A (enrdf_load_stackoverflow) 1967-01-02
DE1514490A1 (de) 1969-06-26

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