US3181042A - Permanent magnet system for focusing an electron beam - Google Patents

Permanent magnet system for focusing an electron beam Download PDF

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Publication number
US3181042A
US3181042A US190890A US19089062A US3181042A US 3181042 A US3181042 A US 3181042A US 190890 A US190890 A US 190890A US 19089062 A US19089062 A US 19089062A US 3181042 A US3181042 A US 3181042A
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US
United States
Prior art keywords
magnet system
electron beam
permanent magnet
tube
bores
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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
US190890A
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English (en)
Inventor
Stock Rolf
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 and Halske AG
Siemens Corp
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Siemens Corp
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Filing date
Publication date
Application filed by Siemens Corp filed Critical Siemens Corp
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    • 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
    • H01J23/087—Magnetic focusing arrangements
    • H01J23/0873—Magnetic focusing arrangements with at least one axial-field reversal along the interaction space, e.g. P.P.M. focusing

Definitions

  • the invention disclosed herein is concerned with a permanent magnet system for focusing at least one electron beam over an extended path, especially for use in connection with travelling field tubes, wherein soft iron parts which are operative to magentically connect the poles of the permanent magnets are provided with bores formed therein for receiving the discharge vessel.
  • the particular feature which is characteristic of the invention resides in making the magnet system separable along a symmetry axis which extends through the bores.
  • Identical poles of the permanent magnets are thereby in electron radiation direction alternately serially connected by pole pieces which have respectively a central bore formed therein for receiving the discharge vessel.
  • the diameter of the bores formed respectively in the pole pieces or in the soft iron cylinder of the indicated prior permanent magnet systems, is so dimensioned, that the tube can be exchangeably inserted into the bores.
  • the bores should be as small as possible so as to obtain a magnetic field which is along the axis of the electron beam as strong as possible.
  • the tube is therefore inserted into the system with its thinner end. This thinner end is in the known travelling field tubes usually the end at which is arranged the collector.
  • the other end of the discharge vessel, in which is disposed the electron gun has a diameter which exceeds that of the central part thereof which contains the delay line.
  • the diameter of the collector exceeds that of the central part of the tube. Accordingly, upon using a permanent magnet system for focusing the beam of such tubes, the bore in the soft iron parts of the magnet system must be larger than the diameter of the part of the discharge vessel in which is contained the delay line. It follows, therefore, that magnets with very high magnetic energy content are required for producing strong magnetic fields along the radiation axis.
  • the object of the present invention is to provide a permanent magnet system for travelling field tubes, especially travelling wave tubes, wherein the bores have a smaller diameter than would be necessary for passing the relatively thick end of the travelling wave tube to be inserted therethrough.
  • FIG. 1 shows in xschematic :manner a separable 1 permanent-magnetsystem for producing a directionally-a1- -ternating magnetic field
  • FIG. 3 represents in schematic sectional view part of the permanent magnet system of FIG. 1 with a travelling field tube extending through bores formed in the soft iron members.
  • numerals 1, 2, 3, 4 indicate magnets which are in known manner arranged axial symmetrically to the electron beam so as to form the sides of a square, with identical poles abutting at the corners of the square.
  • Oppositely disposed corners with identical polarity are, in planes extending perpendicularly to the electron beam axis, alternately interconnected by means of soft iron pole pieces such as indicated at 5, 6, 7, 8. All pole pieces are provided with a central bore 9, such bores being axially aligned for receiving the dis charge vessel.
  • the permanent magnet system shown in FIG. 1 is in accordance with the invention split and separable along the dash lines 10.
  • the system thus comprises two portions between which can be inserted the central part of the discharge tube.
  • FIG. 2 shows as an example a rectangular wave guide 11 which is separable along the dash line 12.
  • the separation line leaves the field pattern, for example, of the H -wave, undisturbed.
  • the lines 13 indicate the high frequency currents of the H wave.
  • FIG. 3 A part of the permanent magnet system of FIG. 1 is shown in FIG. 3 in sectional view in combination with part of a travelling field tube, in order to further explain the advantages obtained by the invention. Since the magnet system can be opened along the line of separation indicated in FIG. 1, the pole pieces 5, 6, 7 and 8 can be brought into positions directly adjacent to the central part of the discharge tube 14 which contains a delay line (not shown), despite the larger diameter of the collector 15.
  • the invention is not inherently limited to details shown and described herein.
  • the invention is particularly likewise applicable in connection with a system comprising ferrite rings or in connection with a permanent magnet system for producing a homogeneous magnetic field.
  • said magnet'system being split to form two parts which are separable along a symmetry plane extending through the axis of said bores for receivdistribution, comprising permanent'magnets arranged axially symmetrically with respect to and extending along said axis, and having pole pieces which are in the axial direction successively disposed for reception of such a tube, said pole pieces alternately magnetically interconnecting identical poles of oppositely positioned permanent magnets, said magnet system being split in a plane extending along the longitudinal axis of mutually aligned successivea a, a a
  • a permanent magnet system according to claim 2, wherein said magnet system has Wave guides built thereinto respectively for the coupling and uncoupling of high frequency energy, said separation plane extending through wall parts or" said Wave guides which are free of the flow Of transverse CUIIGI'ltS.

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US190890A 1961-05-02 1962-04-30 Permanent magnet system for focusing an electron beam Expired - Lifetime US3181042A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DES73780A DE1298197B (de) 1961-05-02 1961-05-02 Permanentmagnetsystem zur gebuendelten Fuehrung des Elektronenstrahls einer Lauffeldroehre

Publications (1)

Publication Number Publication Date
US3181042A true US3181042A (en) 1965-04-27

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Family Applications (1)

Application Number Title Priority Date Filing Date
US190890A Expired - Lifetime US3181042A (en) 1961-05-02 1962-04-30 Permanent magnet system for focusing an electron beam

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US (1) US3181042A (enrdf_load_stackoverflow)
DE (1) DE1298197B (enrdf_load_stackoverflow)
GB (1) GB940055A (enrdf_load_stackoverflow)
NL (1) NL277862A (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5744910A (en) * 1993-04-02 1998-04-28 Litton Systems, Inc. Periodic permanent magnet focusing system for electron beam
US10211021B2 (en) 2016-04-11 2019-02-19 Kla-Tencor Corporation Permanent-magnet particle beam apparatus and method incorporating a non-magnetic metal portion for tunability
US10338002B1 (en) 2016-02-01 2019-07-02 Kla-Tencor Corporation Methods and systems for selecting recipe for defect inspection

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2791718A (en) * 1956-04-23 1957-05-07 Bell Telephone Labor Inc Magnetic structure for traveling wave tubes
US2956193A (en) * 1957-07-11 1960-10-11 Philips Corp Magnet system for travelling wave tubes

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE528454A (enrdf_load_stackoverflow) * 1953-04-29
NL214979A (enrdf_load_stackoverflow) * 1956-03-01
US2985792A (en) * 1958-10-02 1961-05-23 Hughes Aircraft Co Periodically-focused traveling-wave tube

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2791718A (en) * 1956-04-23 1957-05-07 Bell Telephone Labor Inc Magnetic structure for traveling wave tubes
US2956193A (en) * 1957-07-11 1960-10-11 Philips Corp Magnet system for travelling wave tubes

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5744910A (en) * 1993-04-02 1998-04-28 Litton Systems, Inc. Periodic permanent magnet focusing system for electron beam
US10338002B1 (en) 2016-02-01 2019-07-02 Kla-Tencor Corporation Methods and systems for selecting recipe for defect inspection
US10211021B2 (en) 2016-04-11 2019-02-19 Kla-Tencor Corporation Permanent-magnet particle beam apparatus and method incorporating a non-magnetic metal portion for tunability

Also Published As

Publication number Publication date
GB940055A (en) 1963-10-23
DE1298197B (de) 1969-06-26
NL277862A (enrdf_load_stackoverflow)

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