US2764708A - Electron discharge devices - Google Patents

Electron discharge devices Download PDF

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Publication number
US2764708A
US2764708A US410399A US41039954A US2764708A US 2764708 A US2764708 A US 2764708A US 410399 A US410399 A US 410399A US 41039954 A US41039954 A US 41039954A US 2764708 A US2764708 A US 2764708A
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US
United States
Prior art keywords
cathode
anode
sleeve
electron
focussing
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
US410399A
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English (en)
Inventor
Beck Arnold Hugh William
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
International Standard Electric Corp
Original Assignee
International Standard Electric Corp
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 International Standard Electric Corp filed Critical International Standard Electric Corp
Application granted granted Critical
Publication of US2764708A publication Critical patent/US2764708A/en
Anticipated expiration legal-status Critical
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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
    • H01J3/027—Construction of the gun or parts thereof

Definitions

  • the present invention relates to the construction of electron guns designed for the production of high current density electron beams, using magnetic focussing.
  • the cathode and focussing electrode were completely enclosed within the pole piece-anode, and contact was made With the remaining part of the magentic circuit through a disc of ferromagnetic material sealed through the envelope of the tube.
  • the anode-pole piece forms part of the envelope of the tube and completely surrounds the cathode and focussing electrode. It is a particular object of the present invention to provide such a gun which is simple to manufacture and which can readily be assembled so as to attain the necessary accuracy in relative positioning of the gun electrodes.
  • an electron gun for the production of a high current density electron beam to be focussed magnetically, comprising an indirectly heated cathode mounted within a cylindrical focussing electrode having an end cap apertured above the cathode emitting surface and an outer circular flange intermediate its ends, a centrally apertured anode disc of ferromagnetic material abutting against an annular end of, and fitting Within, a generally cylindrical outer sleeve of ferromagnetic material, a cylindrical inner anode sleeve secured to the said disc and surrounding the said focussing electrode, the said inner sleeve having axial portions of different interval diameter to form a shoulder for locating the cathode and focussing electrode with respect to the said anode disc, an annular Washer of insulating material providing an axial location of the said cathode and positioned between the said shoulder and the said outer circular flange, and means for retaining the said anode disc in abutment against the said end of the outer
  • the outer ferromagnetic sleeve is preferably made of an alloy sealing readily to glass, so that a glass closure member, forming a base for the discharge tube, may be sealed at one end and, if desired, a glass envelope portion of the discharge tube may be sealed at the other end of the sleeve.
  • a gun according to the present invention is Well adapted for use in, for example, an all metal construction of tube envelope.
  • Fig. 1 shows a view in longitudinal cross-section of an embodiment of the invention and Fig. 2 shows a transverse section taken in the plane IIII of Fig. 1.
  • the electron gun 1 comprises an indirectly heated cathode 2, having a spherically re-entrant emitting surface.
  • the cathode 2 is supported in a surrounding focussing electrode, generally designated by the numeral 3, formed by a cylindrical member or inner sleeve whose upper end is closed by an end cap 4 which is centrally apertured to disclose, the cathode emitting surface.
  • a surrounding focussing electrode generally designated by the numeral 3
  • the focussing electrode generally designated by the numeral 3
  • the focussing electrode generally designated by the numeral 3
  • the focussing electrode generally designated by the numeral 3
  • an outer circular flange 5 and, in the embodiment shown on the drawing, the lower end of the inner sleeve of electrode 4 carries a further circular flange 6.
  • the anode of the gun comprises a centrally apertured anode disc 7 of ferromagnetic material to which is sweated a cylindrical inner anode sleeve 8 surrounding the focussing electrode3 and having axial portions of different internal diameter, so as to form a shoulder 9.
  • the disc 7 contains a central aperture 11, whose sides are preferably bevelled as shown.
  • the thickness of the anode disc 7 and the relative dispositions of the cathode focussing electrode and anode are preferably such that, under operating conditions a fully space charge limited current is drawn from the cathode and the beam is focussedthrough the anode aperture 11 so as to be substantially parallel to the longitudinal axis of the gun just after its exit from the aperture.
  • the cathode emitting-surface is concave, as illustrated in the drawing, the gun should be dimensioned in the manner disclosed in my aforementioned U. S. application No. 176,925.
  • the gun is then particularly suitable for launching an electron beam in which the electrons move with Brillouin type flow.
  • Brillouin flow is characterised by all the electrons having the same axial velocity and each moving, by virtue of a steady axial magnetic field, in a helix of constant radius about the beam axis with the same angular velocity, so that the motion of the beam is like that of a solid rod rotating about and moving along its axis.
  • a cathode whose emitting surface is concave when viewed from the direction of propagation of the beam, such flow demands that the cathode should be screened from the influence of the axial magnetic field. In the present invention this is achieved by the anode disc 7 and outer sleeve 12 being of ferromagnetic material.
  • the inner anode sleeve 8 should also be constructed of ferromagnetic material.
  • the anode disc 7 forms one pole piece of the magnetic focussing arrangement, yoke members of which may conveniently be clamped about the outer sleeve 12. The yoke members still further improve the magnetic screening of the cathode.
  • an electron gun according to the present invention is well adapted to form part of an all metal discharge tube construction, some convenient means being provided for retaining pressure between the anode disc 7 and the annular ends 13 of the outer sleeve 12, and also between the circular flange of the focussing electrode, the washer 10 and the shoulder 9 on the inner anode sleeve 8, in the embodiment illustrated in the drawing the outer member 12 is constructed of an alloy sealing readily to glass for example, the alloys commercially known as Cinseal (reg. trademark) or that sold as 50:50 Nickel-Iron Alloy and a glass closure member 15 is sealed to the lower end of the outer sleeve 12.
  • the closure member 15 has a conventional glass base 16 carrying pins 17 sealed therethrough.
  • a plurality of rods 18 are secured to the flange 6 at one end and to convenient ones of the pins 17 at the other to maintain the required axial pressure between the various gun electrodes.
  • a glass envelope member 19 of the discharge device, of which the gun forms a part, is butt-sealed to the annular end of 13 of the outer cylinder 12.
  • an electron gun according to the invention is easy to manufacture and assemble and the necessary critical spacings between the electrodes can readily be obtained with accuracy.
  • An electron gun for the production of a high current density electron beam to be focussed magnetically comprising an indirectly heated cathode mounted within a cylindrical focussing electrode having an end cap apertured above the cathode emitting surface and an outer circular flange intermediate its ends, a centrally apertured anode disc of ferromagnetic material abutting against an annular end of, and fitting within, a generally cylindrical outer sleeve of ferromagnetic material, a cylindrical inner anode sleeve secured to the said disc and surrounding the said focussing electrode, the said inner sleeve having axial portions of different internal diameter to form a shoulder for locating the cathode and focussing electrode with respect to the said anode disc, an annular washer of insulating material providing an axial location of the said cathode and positioned between the said shoulder and the said outer circular flange, and means for retaining the said flange in abutment against the said annular Washer and the washer against the said shoulder, and for
  • An electron gun according to claim 2 in which the said means for retaining the anode disc in abutment against the said outer sleeve annular end, together with the said shoulder, washer and outer circular flange in respective abutment; comprises a plurality of rods each of which is secured at one end to the said focussing cylinder and at the other end to the said glass closure member.
  • an electron gun according to claim 1 in which the said outer sleeve is of a material sealing readily to glass, a cylindrical glass envelope portion of the said discharge device being buttsealed to the said annular end of the outer sleeve.
  • An electron gun according to claim 1 in which the anode disc is so dimensioned and the cathode and focussing electrodes are so positioned relative thereto that under operating conditions a space charge limited electron beam is projected from the gun substantially parallel to the beam axis slightly beyond the exit from the aperture of the anode disc.

Landscapes

  • Microwave Tubes (AREA)
  • Electron Sources, Ion Sources (AREA)
  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
US410399A 1953-03-20 1954-02-15 Electron discharge devices Expired - Lifetime US2764708A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB319035X 1953-03-20

Publications (1)

Publication Number Publication Date
US2764708A true US2764708A (en) 1956-09-25

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ID=10330106

Family Applications (1)

Application Number Title Priority Date Filing Date
US410399A Expired - Lifetime US2764708A (en) 1953-03-20 1954-02-15 Electron discharge devices

Country Status (6)

Country Link
US (1) US2764708A (is")
BE (1) BE527412A (is")
CH (1) CH319035A (is")
DE (1) DE1005199B (is")
FR (1) FR1095762A (is")
GB (1) GB729611A (is")

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2961562A (en) * 1958-05-05 1960-11-22 Gen Electric Oscillation suppression in high voltage electron guns
US3204141A (en) * 1962-08-20 1965-08-31 Kentucky Electronics Inc Electron gun
US3217200A (en) * 1962-01-23 1965-11-09 Gen Electric Internal magnetic lens for electron beams
US3319102A (en) * 1962-08-20 1967-05-09 Kentucky Electronics Inc Electron gun assembly with increased cooling surfaces

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1165763B (de) * 1960-02-06 1964-03-19 Telefunken Patent Kathodenstrahlroehre mit zwei in verschiedenen Ebenen senkrecht zur Roehrenachse angeordneten Ablenkmitteln

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2378569A (en) * 1940-03-29 1945-06-19 Messner Maximilian Cathode-ray tube
US2386790A (en) * 1944-11-29 1945-10-16 Sylvania Electric Prod Electron gun and the like
US2436265A (en) * 1945-07-27 1948-02-17 Du Mont Allen B Lab Inc Cathode-ray tube
US2476060A (en) * 1945-01-11 1949-07-12 Cossor Ltd A C Electron gun structure
US2644906A (en) * 1951-08-11 1953-07-07 Gen Electric Electron beam discharge device

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE680284C (de) * 1932-03-17 1939-08-25 Bodo Von Borries Dr Ing Magnetische Sammellinse kurzer Feldlaenge

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2378569A (en) * 1940-03-29 1945-06-19 Messner Maximilian Cathode-ray tube
US2386790A (en) * 1944-11-29 1945-10-16 Sylvania Electric Prod Electron gun and the like
US2476060A (en) * 1945-01-11 1949-07-12 Cossor Ltd A C Electron gun structure
US2436265A (en) * 1945-07-27 1948-02-17 Du Mont Allen B Lab Inc Cathode-ray tube
US2644906A (en) * 1951-08-11 1953-07-07 Gen Electric Electron beam discharge device

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2961562A (en) * 1958-05-05 1960-11-22 Gen Electric Oscillation suppression in high voltage electron guns
US3217200A (en) * 1962-01-23 1965-11-09 Gen Electric Internal magnetic lens for electron beams
US3204141A (en) * 1962-08-20 1965-08-31 Kentucky Electronics Inc Electron gun
US3319102A (en) * 1962-08-20 1967-05-09 Kentucky Electronics Inc Electron gun assembly with increased cooling surfaces

Also Published As

Publication number Publication date
BE527412A (is")
DE1005199B (de) 1957-03-28
GB729611A (en) 1955-05-11
FR1095762A (fr) 1955-06-06
CH319035A (de) 1957-01-31

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