US3745401A - Filament support structure for large electron guns - Google Patents

Filament support structure for large electron guns Download PDF

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Publication number
US3745401A
US3745401A US00226472A US3745401DA US3745401A US 3745401 A US3745401 A US 3745401A US 00226472 A US00226472 A US 00226472A US 3745401D A US3745401D A US 3745401DA US 3745401 A US3745401 A US 3745401A
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US
United States
Prior art keywords
springs
filament
support structure
tray
leaf
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
US00226472A
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English (en)
Inventor
R Stapleton
J Hayden
J Weinbrecht
E Ferdinand
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US Atomic Energy Commission (AEC)
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US Atomic Energy Commission (AEC)
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Publication date
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/09—Processes or apparatus for excitation, e.g. pumping
    • H01S3/097—Processes or apparatus for excitation, e.g. pumping by gas discharge of a gas laser
    • H01S3/09707—Processes or apparatus for excitation, e.g. pumping by gas discharge of a gas laser using an electron or ion beam
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
    • H01J1/02—Main electrodes
    • H01J1/13—Solid thermionic cathodes
    • H01J1/15—Cathodes heated directly by an electric current
    • H01J1/18—Supports; Vibration-damping arrangements
    • 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
    • H01J3/027—Construction of the gun or parts thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/02—Constructional details
    • H01S3/03—Constructional details of gas laser discharge tubes
    • H01S3/038—Electrodes, e.g. special shape, configuration or composition

Definitions

  • each leaf has one or more slots in its upper edge.
  • the arms of each slot curve substantially outwardly from the opposing leaf springs, whereby a filament having enlarged end portions inserted in the slots of opposing leaf springs is held firmly in place under tension. Damaged or destroyed filaments may readily be removed and new filaments inserted by pressing opposed leafs toward each other, removing one filament, inserting another, and releasing the springs.
  • the invention described herein was made in the course of, or under, a contract with the U. S. ATOMIC ENERGY COMMISSION. It relates to a support structure for electron emitting filaments in electron guns and more specifically to a support structure for such filaments which allows quick and easy replacement of destroyed or damaged filaments.
  • filament means any elongated structure, such as a wire, rod, or bar of a material which when heated to an appropriate temperature acts as a strong electron emitter.
  • the term filament further encompasses woven or otherwise interconnected structures of an electron-emitter material having end portions periodically extending therefrom on opposing edges.
  • filament support structures are known in the art. They all have the disadvantages of either not allowing easy installation and removal of filaments or of presenting large heat sinks to the ends of the filaments.
  • one commercially available vacuum tube electron gun uses a capture assembly in which filaments are fed through holes before they are finally attached to the support structure, thus eliminating easy and quick installation and removal.
  • Another commerically available vacuum tube electron gun uses a T-bar arrangement as a latching method to hold a filament in a massive end plate, thus producing a large heat sink which causes end cooling of the filament (in turn directly affecting its electron output) and making installation and removal more difficult.
  • a plurality of opposing leaf springs are mounted on a filament tray with the leaf of each spring extending outwardly from the tray at a substantial angle.
  • each leaf extends substantially perpendicularly to the tray, forming an angle slightly greater than 90 with its own base plate; however, this need not be so.
  • Each leaf has one or more slots in its upper edge, with the arms of each slot curving substantially outwardly from the opposing leaf springs.
  • Opposing leaf springs are so spaced that filaments having enlarged end portions inserted into the slots of opposed leafs are held firmly in placed under tension. Damaged or destroyed filaments may readily be removed and new filaments inserted by pressing opposing leafs toward each other, removing one filament, inserting another, and releasing the springs.
  • the filament support structure of this invention has particular utility with large electron guns used with electron beam controlled gas laser systems.
  • FIG. 1 is a cross-sectional view of an electron beam controlled CO laser amplifier utilizing the filament support structure of this invention.
  • FIG. 2 is a cut-a-way view of the laser of FIG. 1.
  • FIG. 3 shows a portion of the filament support structure used in the laser of FIGS. 1 and 2.
  • FIG. 4 is an isometric projection of one of the veeshaped leaf springs shown in FIG. 3.
  • ionization of a laser medium 10 consisting of a mixture of CO N and He at atmospheric pressure and above in optical cavity 11 is initiated and maintained by a high energy electron beam 14 which penetrates the laser gas volume.
  • the laser medium is. pumped by an electrical discharge established between cathode 7 and anode 9. This charge imparts an electric field to the gas mixture which is optimum for excitation of the upper CO laser level, and whose current density, and hence rate of electrical energy deposition, is determined by the electron density established by the secondary ionization produced by electron beam 14.
  • Beam 14 is produced by means of electron gun 15 operating in vacuum chamber 2.
  • a vacuum of 5 X 10 Torr or better is drawn in chamber 2 by means of vacuum manifold I.
  • An appropriatevoltage 5 to 8 seconds in duration is applied in gun 15 to heat the thoriated tungsten filaments 5 held in filament support structure 15by means of leaf springs 4 mounted on filament tray 3.
  • Electrons emitted by the heated filaments 5 are accelerated through vacuum window 6 into laser medium 10 where they effectively sweep through a volume of 1 meter by 5 cm by 5 cm producing substantial ionization in the gas within this volume
  • An effective optical cross section 8 within this volume is swept by an oscillator laser pulse along optical axis 13 to produce an amplified pulse of laser light.
  • a portion of filament support structure 15 is shown in more detail in FIG. 3.
  • a plurality of leaf springs 4 which serve as holders for filaments 5 are mounted on filament tray 3 and insulated therefrom by means of insulators 16. Facing leaf springs are mounted sufficiently far apart that when the filaments are inserted they are held under tension by the springs.
  • the leafs of all the springs consist of vee-shaped segments 18 extending outward from the tray and having a mounting slot 19 for a filament in the top portion of each arm 20 of the vee.
  • a leaf spring having such a vee-shaped leaf is shown in FIG. 4.
  • each filament 5 may consist of wire, rods, bars, or any other desired shape and material consistent with the type of electron beam sought to be produced. As shown in FIG. 3, each filament 5 has a head 25 at each end such that when oppositely facing leaf springs are flexed inward and the filament inserted in the slots of opposed vee arms, the beads make contact with the outwardly curved portion of the arms and the filament is held rigidly under tension when the springs are released. To replace any particular filament the opposing arms of the leaf springs on which it is mounted are flexed inward, the filament removed, a new one inserted, and the leafs allowed to relax outward, thus holding the new filament in place under tension.
  • the preferred embodiment has TZM leaf springs 4, a TZM filament tray 3, sapphire insulators 16, and the filaments 5 are composed of 0.028-in. thoriated tungsten wire having beaded ends.
  • TZM is a standard alloy consisting of 0.5 wt Ti, 0.1 wt Zr, and 99 wt Mo. Molybdenum is the preferred material for leaf springs 4 because of its low thermal conductivity, high stability and strength at design temperatures, and high work function.
  • the filament support structure used in the laser amplifier of FIGS. 1 and 2 holds 102 filaments.
  • the rest angle 22 of an individual leaf spring 4 used in the preferred embodiment is 105. By rest angle is meant the angle between the base plate 23 and the leaf 21 when the leaf is unflexed.
  • the rest angle of the spring is not critical except insofar as it affects the tension placed on the filament. It will be readily understood by one of reasonable skill in the spring art that the flexure strength of the leaf springs used with this preferred embodiment is dependent on the type of material used to make the spring,
  • the filament support structure of the preferred embodiment has been evaluated for a filament temperature range of 800 to 3000C and filament lengths from 3 to 30 cm.
  • the maximum temperature for destruction was about 3300C, at which time a pure tungsten filamerit melted with no apparent damage to the support structure.
  • An electron gun filament support structure comprising a filament tray, a plurality of opposing leaf springs mounted on said tray, the leafs of said springs forming a substantial rest angle with their base plates and being of an appropriate geometrical shape to have more than one arm with a slot in the upper edge of each arm, the upper portion of each arm curving outwardly from the opposing leaf springs, and opposed springs so distanced that electron-emitting filaments having enlarged end portions may be firmly held under tension in the slots of said opposed springs, means for insulating said springs from said tray, and means for mounting said leaf springs on said tray.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Optics & Photonics (AREA)
  • Solid Thermionic Cathode (AREA)
  • Lasers (AREA)
  • Electron Sources, Ion Sources (AREA)
US00226472A 1972-02-15 1972-02-15 Filament support structure for large electron guns Expired - Lifetime US3745401A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US22647272A 1972-02-15 1972-02-15

Publications (1)

Publication Number Publication Date
US3745401A true US3745401A (en) 1973-07-10

Family

ID=22849036

Family Applications (1)

Application Number Title Priority Date Filing Date
US00226472A Expired - Lifetime US3745401A (en) 1972-02-15 1972-02-15 Filament support structure for large electron guns

Country Status (5)

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US (1) US3745401A (enrdf_load_stackoverflow)
JP (1) JPS4890463A (enrdf_load_stackoverflow)
DE (1) DE2307531A1 (enrdf_load_stackoverflow)
FR (1) FR2172230B1 (enrdf_load_stackoverflow)
GB (1) GB1370753A (enrdf_load_stackoverflow)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3917968A (en) * 1974-02-22 1975-11-04 Texas Instruments Inc Area flood gun
US4080546A (en) * 1974-10-16 1978-03-21 Steigerwald Strahltechnik Gmbh Beam splitter for electron beam machines
US4695677A (en) * 1985-06-06 1987-09-22 Ruth Dale G Wire tensioning system
US5204583A (en) * 1990-10-24 1993-04-20 Samsung Electron Devices Co., Ltd. Filament supporter for use in vacuum fluorescent display tubes and method for filament installation
EP0550134A1 (en) * 1991-12-30 1993-07-07 Energy Sciences Inc. Filament clip support
US6555948B1 (en) * 1998-09-24 2003-04-29 Patent-Treuhand-Gesellschaft Fuer Elektrische Gluehlampen Mbh Electric incandescent lamp
US7002288B2 (en) * 2001-02-20 2006-02-21 Futaba Corporation Electron tube and method for producing the same
US20060124055A1 (en) * 2003-05-28 2006-06-15 Walter Franken Mask-retaining device

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE372759A (enrdf_load_stackoverflow) * 1929-09-25
US3506871A (en) * 1967-05-29 1970-04-14 Air Reduction Electron beam gun having elongated tensioned emitter

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3917968A (en) * 1974-02-22 1975-11-04 Texas Instruments Inc Area flood gun
US4080546A (en) * 1974-10-16 1978-03-21 Steigerwald Strahltechnik Gmbh Beam splitter for electron beam machines
US4695677A (en) * 1985-06-06 1987-09-22 Ruth Dale G Wire tensioning system
US5204583A (en) * 1990-10-24 1993-04-20 Samsung Electron Devices Co., Ltd. Filament supporter for use in vacuum fluorescent display tubes and method for filament installation
EP0550134A1 (en) * 1991-12-30 1993-07-07 Energy Sciences Inc. Filament clip support
US6555948B1 (en) * 1998-09-24 2003-04-29 Patent-Treuhand-Gesellschaft Fuer Elektrische Gluehlampen Mbh Electric incandescent lamp
US7002288B2 (en) * 2001-02-20 2006-02-21 Futaba Corporation Electron tube and method for producing the same
US20060124055A1 (en) * 2003-05-28 2006-06-15 Walter Franken Mask-retaining device

Also Published As

Publication number Publication date
DE2307531A1 (de) 1973-08-23
GB1370753A (en) 1974-10-16
FR2172230A1 (enrdf_load_stackoverflow) 1973-09-28
JPS4890463A (enrdf_load_stackoverflow) 1973-11-26
FR2172230B1 (enrdf_load_stackoverflow) 1978-02-10

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