US3454806A - System for the production of a flat electron beam for a traveling wave tube with purely electrostatic focusing - Google Patents

System for the production of a flat electron beam for a traveling wave tube with purely electrostatic focusing Download PDF

Info

Publication number
US3454806A
US3454806A US564335A US3454806DA US3454806A US 3454806 A US3454806 A US 3454806A US 564335 A US564335 A US 564335A US 3454806D A US3454806D A US 3454806DA US 3454806 A US3454806 A US 3454806A
Authority
US
United States
Prior art keywords
electron beam
cathode
electrode
potential
acceleration anode
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
US564335A
Other languages
English (en)
Inventor
Hannjorg Bittorf
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.)
Siemens AG
Siemens Corp
Original Assignee
Siemens 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 Siemens Corp filed Critical Siemens Corp
Application granted granted Critical
Publication of US3454806A publication Critical patent/US3454806A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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
    • H01J23/08—Focusing arrangements, e.g. for concentrating stream of electrons, for preventing spreading of stream
    • H01J23/083—Electrostatic focusing arrangements
    • 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

Definitions

  • An electron beam of flat cross-section is provided in a traveling wave tube, the electron beam being directed at 90 from the cathode to an aperture in an anode and having beam deflecting electrodes disposed between a deflection plate and cathode and the cathode and the anode for focusing the electron beam.
  • the invention concerns an electron beam production system for a traveling wave tube with purely electrostatic focusing, which contains a cathode, a diaphragmshaped acceleration anode and at least one beam forming electrode which cooperate to produce an electron beam of flat cross section which is directed into a helical course on which the electron beam travels along a delay line in the field of a cylindrical condenser.
  • Traveling wave tubes are known, in which an electron beam is directed purely electrostatically on a helical course between a delay line and an outer electrode.
  • the delay line is charged with a high positive direct potential in comparison with that of the outer electrode whereby the outwardly directed centrifugal force of the electron beam is compensated by an electrostatic counter force.
  • Traveling wave tubes of this kind with purely electrostatic focusing of the electron beam are normally designated as E-type tubes, and generally operate with a flat electron beam, in which case the problem arises of directing the first beam, the production of which is supposed to take place in a purely electrostatic manner, exactly tangentially to a certain radius into the desired helical course.
  • electron guns have been utilized which consist of a cathode and several slit diaphragms, in which the emission plane of the cathode is located in a plane perpendicularly to a tangent of the helical electron beam course.
  • Such electron guns exhibit only a small beam density.
  • such known flat beam guns for E-type tubes offer only few possibilities to influence the focusing of the electron beam during the discharge thereof into the field of the cylindrical condenser.
  • An electron beam production system presents, first of all, the advantage that for a relatively small cathode loading very high current densities of the electron beam leaving the acceleration anode may be obtained. For example, with a cathode loading of approximately 1 a./cm. a flat beam with a current density of approximately 10 a./cm. may be obtained without difficulty.
  • a further important advantage of the invention resides in the fact that by regulation of the voltages which are applied to the individual electrodes, the electron beam may be tilted and simultaneously shifted in radial direction to the helical course.
  • the gun field is shielded with respect to the field of the cylindrical condenser by the diaphragm-shaped acceleration anode so that a voltage regulation at the gun does not have any disturbing effects on the beam course in the actual drift space of the tube.
  • a small plate condenser which provides a further possibility for the beam correction may be additionally arranged behind the acceleration anode.
  • FIG. 1 is a schematic sectional view of an electron beam producing system embodying the invention
  • FIG. 2 is a sectional view similar to FIG. 1, illustrating the use of a condenser structure
  • FIG. 3 is a graph illustrating the current density distribution of an electron beam with utilization of the present invention.
  • the reference numeral 1 designates a cathode, for example an MK cathode having, for example, a diameter of 3 mm. which is surrounded by a Wehnelt electrode 2, which is provided with a slit 3, by means of which an electron bundle 4, for example with 1.8 mm. width and 5 mm. height, is derived from the electron flow emitted from the cathode 1 by means of the diaphragm action of the slit 3.
  • a cathode for example an MK cathode having, for example, a diameter of 3 mm. which is surrounded by a Wehnelt electrode 2, which is provided with a slit 3, by means of which an electron bundle 4, for example with 1.8 mm. width and 5 mm. height, is derived from the electron flow emitted from the cathode 1 by means of the diaphragm action of the slit 3.
  • a diaphragm-shaped accelerating anode 5 Disposed at an angle of 90 with respect to the effective cathode surface, is a diaphragm-shaped accelerating anode 5, which extends perpendicularly to the electron beam direction at the entrance point of the electron beam 4 into the field of a cylindrical condenser (not illustrated), which follows the acceleration anode.
  • the acceleration anode 5 is, at its end adjacent to the cathode 1, provided with an extension, such as a flange 6 which runs parallel to the effective cathode surface and extends to within the proximity of the electron flow from the cathode 1.
  • a plate-like deflection electrode 7 On the side of the system opposite to the cathode surface is disposed a plate-like deflection electrode 7 which is to be at a potential approximately equal to that of the cathode.
  • the deflection electrode 7 is provided at its end, adjacent to the acceleration anode 5, with an extension 8 which is disposed opposite to the extension 6 of the acceleration anode 5.
  • Such an angle-shape of the deflection electrode is desirable as the upper boundary of the electron beam 4 must be bent more than the lower boundary thereof during the deflection.
  • a first beam forming electrode 9 which is to be at an electrical potential lying between that of the cathode and that of the acceleration anode.
  • a second beam forming electrode 10 On the other side of the electron beam 4 is disposed a second beam forming electrode 10 which is positioned at approximately equal distances from the Wehnelt electrode 2 and the deflection electrode 7, said second beam forming electrode having a cylindrical shape and having a potential which is substantially the same as that of the first beam forming electrode 9.
  • a further plate-shaped beam forming electrode 11 disposed below the cylindrical beam forming electrode 10 is a further plate-shaped beam forming electrode 11 which is disposed laterally of the electron course and extends substantially perpendicularly to the plane of the cathode.
  • the electrode system illustrated in FIG. 1 with the described potentials creates a potential distribution as indicated by the potential lines 12 in FIG. 1.
  • the deflection and the simultaneous concentration of the electron flow proceeding fram the cathode 1 in the direction towards the diaphragm opening 13 of the acceleration anode is based upon such potential distribution.
  • the Wehnelt electrode 2 with the Wehnelt slit 3 serves, in particular, for the defining and limiting of the beam cross section. It also prevents, in known manner, a spreading of the electron beam through space charge forces.
  • the potential of the Wehnelt electrode 2 lies between cathode potential and a negative tenth part of the acceleration anode potential, while the voltage at the two beam forming electrodes 9 and preferably amounts to one tenth to four tenths of the acceleration anode potential.
  • the size of the latter voltage primarily determines the strength of the emission current and the positioning of the focus of the fiat electron beam 4.
  • the cross sectional shape of the beam forming electrode 10 does not necessarily have to be circular. It is only important that the field distribution indicated by the lines 12 is substantially achieved.
  • the additional plate-shaped beam shaping electrode 11 which is to lie on a potential between cathode potential and a cathode potential reduced 'by one tenth of the acceleration anode potential, together with the beam forming electrode 9 and the part 6 of the acceleration anode 5 makes possible a precise correction of the beam course.
  • an overlapping of the beam boundaries may be avoided because the electrode 11 principally influences the upper boundary of the beam while the course of the lower boundary of the beam is determined by the beam forming electrode 9 and the extension 6 located at the acceleration anode 5.
  • the deflection electrode 7, lying approximately on cathode potential principally causes the deflection of the electron beam 4.
  • This electrode also enables an influencing of the angle of emergence of the electron beam 4 from the diaphragm opening 13 of the acceleration anode 5 during which process the beam may also be shifted somewhat laterally.
  • the shape of the acceleration anode is, on the one hand, determined by the fact that the gun field is supposed to be strictly separated from the field of the actual drift space in order to avoid a reciprocal influencing of the two fields.
  • the angled extension 6 at the .acceleration anode 5 is provided for cooperation with the two essential beam forming electrodes 9 and 10, to obtain the desired beam shape.
  • the acceleration anode may, of course, also consist of two separate parts, namely, the plate 5 with the diaphragm opening 13 and a separate plate perpendicular to the first plate, corresponding to the extension 6.
  • FIG. 3 illustrates the measured current density distribution of a fiat electron beam which has been produced by means of a gun .according to FIG. 1.
  • d designates the width of the beam cross-section, with its height amounting to 5 mm.
  • the measurements were taken with the following voltages at the individual electrodes.
  • Applied to the beam forming electrode 9 was a potential of 53 v. and to the cylindrical beam forming electrode 9 a potential of 41 v., while the potential of the acceleration anode 5 amounted to 410 v.
  • the beam was concentrated at a perveance of 0.7- 10 a./v. in the ratio of 10:1, with its emergence angle after the passage from the acceleration anode amounting to approximately 5.
  • the cathode surface may be concavely formed and the Wehnelt electrode may have a larger dimension so that the electron beam initially becomes more convergent whereby an even higher beam concentration may be obtained.
  • the arrangement of the other electrodes may be the same as in FIG. 1.
  • the individual beam forming electrodes may also have a different shape if by this feature the illustrated potential distribution in the gun space is essentially retained.
  • An electron beam production system for a traveling wave tube which utilizes purely electrostatic focusing in which an electron beam of flat cross-section is to be brought into a helical course on which the electron beam is to travel along a delay line in the field of a cylindrical condenser, the production system comprising:
  • a cathode including a cathode surface for emitting a flow of electrons
  • a Wehnelt electrode surrounding said cathode and having a rectangular aperture therein for deriving an electron beam of rectangular cross-section from the electron flow emitted from said cathode;
  • an acceleration anode having a diaphragm opening therein, said acceleration anode being positioned at the entrance point of the electron beam into the field of such a cylindrical condenser for separating the electrostatic field present in the space of the beam production system, said cathode surface being disposed laterally of said acceleration anode and at substantially 90 thereto, said acceleration anode including an end adjacent said cathode and an end portion which extends substantially parallel to said cathode surface and to within the proximity of the electron flow from said cathode surface;
  • said deflection electrode oppositely disposed With respect to said cathode for operating at substantially the same potential .as said cathode, said deflection electrode being of generally planar shape and including an end which faces said acceleration anode and extends at a right angle to the plane of said deflection electrode in the direction toward said end portion of said acceleration electrode; and
  • beam forming electrodes operatively disposed between said cathode and said acceleration anode, and between said cathode and said deflection electrode, for operating at such a potential between that of said cathode and said acceleration anode so as to deflect the electron flow from said cathode surface by 90 in the direction toward the diaphragm opening of said acceleration anode.
  • one of the beam forming electrodes is in the form of a plate and extends into the space between the Wehnelt electrode and the extended end of the acceleration anode, another of said beam forming electrodes having a cylindrical form and disposed at the opposite side of the electron flow and spaced equi-distant from the Wehnelt electrode and the deflection electrode.
  • An electron beam production system wherein the two beam forming electrodes are disposed to receive substantially the same potential, with such potential amounting to one tenth of four tenths of the acceleration anode potential.
  • An electron beam production system wherein on that side of the cylindrical beam forming electrode facing away from the deflection electrode, there is disposed a further beam forming electrode of plate-like shape which is laterally spaced from the electron flow and extends substantially perpendicularly to the effective cathode plane and which, together with the Wehnelt electrode, is to be at substantially the potential of said cathode.
  • An electron beam production system wherein there is provided a plate condenser which surrounds the discharge course, and with respect to the discharge direction extends behind the diaphragm opening of the acceleration anode.

Landscapes

  • Electron Sources, Ion Sources (AREA)
  • Microwave Tubes (AREA)
US564335A 1965-07-15 1966-07-11 System for the production of a flat electron beam for a traveling wave tube with purely electrostatic focusing Expired - Lifetime US3454806A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DES0098199 1965-07-15

Publications (1)

Publication Number Publication Date
US3454806A true US3454806A (en) 1969-07-08

Family

ID=7521296

Family Applications (1)

Application Number Title Priority Date Filing Date
US564335A Expired - Lifetime US3454806A (en) 1965-07-15 1966-07-11 System for the production of a flat electron beam for a traveling wave tube with purely electrostatic focusing

Country Status (4)

Country Link
US (1) US3454806A (cs)
DE (1) DE1491461A1 (cs)
GB (1) GB1146546A (cs)
NL (1) NL6608679A (cs)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2821597A1 (de) * 1978-05-17 1979-11-22 Siemens Ag Verwendung eines systems zur erzeugung eines elektronenflachstrahls mit rein elektrostatischer fokussierung in einer roentgenroehre
RU2267185C1 (ru) * 2004-03-29 2005-12-27 Федеральное государственное унитарное предприятие "Научно-производственное предприятие "Исток" (ФГУП "НПП "Исток") Лампа бегущей волны
US20060175575A1 (en) * 2001-06-15 2006-08-10 Kaplan Warren A Method for preparing phthalate polyester polyol-based dimensionally stable spray polyurethane foam
CN108878236A (zh) * 2018-07-10 2018-11-23 电子科技大学 一种行波管电子枪中热初速效应的抑制方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2442848A (en) * 1942-03-09 1948-06-08 Farnsworth Res Corp Electron control tube
US2807739A (en) * 1950-08-12 1957-09-24 Csf Devices of focusing of electronic beams
US2857548A (en) * 1955-06-10 1958-10-21 Bell Telephone Labor Inc Electron beam system
US2900558A (en) * 1957-07-18 1959-08-18 Hewlett Packard Co Beam-type tube
US3189785A (en) * 1960-04-25 1965-06-15 Bell Telephone Labor Inc Pre-interaction cycloidal beam deflection in crossed-field tube

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2442848A (en) * 1942-03-09 1948-06-08 Farnsworth Res Corp Electron control tube
US2807739A (en) * 1950-08-12 1957-09-24 Csf Devices of focusing of electronic beams
US2857548A (en) * 1955-06-10 1958-10-21 Bell Telephone Labor Inc Electron beam system
US2900558A (en) * 1957-07-18 1959-08-18 Hewlett Packard Co Beam-type tube
US3189785A (en) * 1960-04-25 1965-06-15 Bell Telephone Labor Inc Pre-interaction cycloidal beam deflection in crossed-field tube

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2821597A1 (de) * 1978-05-17 1979-11-22 Siemens Ag Verwendung eines systems zur erzeugung eines elektronenflachstrahls mit rein elektrostatischer fokussierung in einer roentgenroehre
US20060175575A1 (en) * 2001-06-15 2006-08-10 Kaplan Warren A Method for preparing phthalate polyester polyol-based dimensionally stable spray polyurethane foam
RU2267185C1 (ru) * 2004-03-29 2005-12-27 Федеральное государственное унитарное предприятие "Научно-производственное предприятие "Исток" (ФГУП "НПП "Исток") Лампа бегущей волны
CN108878236A (zh) * 2018-07-10 2018-11-23 电子科技大学 一种行波管电子枪中热初速效应的抑制方法
CN108878236B (zh) * 2018-07-10 2020-05-12 电子科技大学 一种行波管电子枪中热初速效应的抑制方法

Also Published As

Publication number Publication date
NL6608679A (cs) 1967-01-16
GB1146546A (en) 1969-03-26
DE1491461A1 (de) 1969-05-14

Similar Documents

Publication Publication Date Title
US2274586A (en) Cathode ray tube
KR920001833B1 (ko) 개량된 전극구조를 구비한 컬러수상관용 전자총
US2472766A (en) Cathode-ray tube
US5404071A (en) Dynamic focusing electron gun
US3496406A (en) Cathode ray tubes with electron beam deflection amplification
US2617060A (en) Cathode-ray tube
US2464562A (en) Discharge tube
US3454806A (en) System for the production of a flat electron beam for a traveling wave tube with purely electrostatic focusing
US2971118A (en) Electron discharge device
US2827592A (en) Post-acceleration cathode ray tube
US3497763A (en) Grid to compensate for astigmatic quadrupolar lens
US2981864A (en) Image display device
GB1078832A (en) Electrostatic electron optical system
GB1226886A (cs)
US3696261A (en) Cathode ray tube with plural beams for each color element
US3139552A (en) Charged particle gun with nonspherical emissive surface
US2173165A (en) Electron tube
US2228958A (en) Cathode ray tube
US2890379A (en) Distortion correction in cathode-ray tubes
US4334170A (en) Means and method for providing optimum resolution of T.V. cathode ray tube electron guns
US3962599A (en) Shielding means for cathode ray tube
US2971108A (en) Electron discharge device
US2160021A (en) Electrode arrangement for cathode ray tubes
US2225786A (en) Secondary emitting tube
US2564743A (en) Charged particle beam forming apparatus