US3454809A - Circular electron multiplier and permeable anode - Google Patents

Circular electron multiplier and permeable anode Download PDF

Info

Publication number
US3454809A
US3454809A US599004A US3454809DA US3454809A US 3454809 A US3454809 A US 3454809A US 599004 A US599004 A US 599004A US 3454809D A US3454809D A US 3454809DA US 3454809 A US3454809 A US 3454809A
Authority
US
United States
Prior art keywords
dynode
electrons
electron
anode
dynodes
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
US599004A
Other languages
English (en)
Inventor
Robert H Clayton
Edward H Eberhardt
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.)
TDK Micronas GmbH
ITT Inc
Original Assignee
Deutsche ITT Industries GmbH
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 Deutsche ITT Industries GmbH filed Critical Deutsche ITT Industries GmbH
Application granted granted Critical
Publication of US3454809A publication Critical patent/US3454809A/en
Assigned to ITT CORPORATION reassignment ITT CORPORATION CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). Assignors: INTERNATIONAL TELEPHONE AND TELEGRAPH CORPORATION
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
    • H01J43/00—Secondary-emission tubes; Electron-multiplier tubes
    • H01J43/04—Electron multipliers
    • H01J43/06—Electrode arrangements
    • H01J43/18—Electrode arrangements using essentially more than one dynode
    • H01J43/20—Dynodes consisting of sheet material, e.g. plane, bent

Definitions

  • Electron multiplier dynodes are circularly arranged around and spaced from a permeable anode. Means are provided to accelerate and direct electrons through the anode onto successive dynode surfaces displaced circumferentially from a diametrically opposed position.
  • multiplier configurations having different performance characteristics leading to different end uses.
  • One use for a multiplier of this type is to amplify current in television camera tubes such as image dissectors and the like. Such multipliers should have good sensitivity and high ampliiication factors.
  • electrons In achieving this performance, electrons must be accelerated toward each dynode -with a high enough velocity that they will generate secondary electrons on impact at a ratio greater than unity. The electrons during their passage from one Idynode to another must be so controlled that as many electrons as possible impact the dynode.
  • a further requirement for some applications involves the uniformity in transit time of all of the electrons from one dynode to the next, such that electrons leaving one dynode at any given instant of time will arrive at a succeeding dynode simultaneously.
  • an electron multiplier having a series of dynodes arranged circularly in circumferentially spaced relation. These dynodes are provided with surfaces arranged and shaped as 'discontinuous segments of a cylinder. Disposed within these surfaces is an electron permeable anode or accelerator which develops a coaxial, cylindrically shaped, iield-free space through which electrons may travel in moving from one dynode surface to another.
  • some means such as a magnetic tield, which deflects the electron streams inside the field-free space along paths slightly 3,454,809 Patented July 8, 1969 ICC angularly removed from a straight, diametral direction.
  • FIG. l is a diagrammatic illustration of an embodiment of this inveniton and is used in explaining the construction and operating principles thereof;
  • FIG. 2 is a similar diagrammatic illustration used in explaining the formation of the electron streams between dynodes
  • FIG. 3 is a cross-sectional view of a working embodiment of this invention.
  • FIG. 4 is a sectional View taken substantially along section line 4--4 of FIG. 3 and FIG. 5 is a curve Iused in further explaining operation.
  • a cylindrical, evacuated envelope 1 encloses a series of circularly arranged dynodes 2, 3, 4, 5, 6 and 7 circumferentially spaced apart as shown, a translucent photocathode 8 circumferentially positioned between the dynodes 4 and 6 and a collector electrode 9 positioned in like manner between the dynodes 3 and 5. All of these dynodes, the cathode 8 and the collector 9 have inner surfaces shaped as discontinuous segments of a cylinder having a common axis 10. For the dynodes, 2 through 7, surfaces 11 are of a material which is secondary emissive at a ratio greater than unity.
  • the photocathode 8 shown in this embodiment comprises a glass backing of the aforementioned part-cylindrical shape having a photoelectric coating 12 on the inner surface thereof.
  • anode element or mesh 17 which in this case is in the form of a cylindrically Shaped wire screen positioned coaxially about the axis within the surfaces 11. Either the same screen material or non-magnetic, metal discs may be used to close the opposite ends 18 and 19 of the anode 17.
  • the anode 17 is positioned as closely as possible to the inner surfaces of the dynode, cathode and collector elements for a purpose which will be explained more fully later on.
  • a solenoid 20 coaxially surrounds the envelope 1 as shown and has a variable source of potential, such as battery 21, connected thereto.
  • FIGS. 1 and 2 For an explanation of the operation of the multiplier just described.
  • Potentials are connected to the various dynodes, the cathode 8 and the collector 9 as shown.
  • the photocathode 8 is grounded, or in other words is connected to a reference potential, while the dynodes 2 through 7 and the collector 9 have successively higher potentials, respectively, connected thereto.
  • the anode 17 has applied thereto a higher potential than any of the foregoing, typical potential values being shown in FIG. 1.
  • the solenoid 20 is so operated as to provide an axially extending, magnetic fiel-d centrally axially positioned as indicated by the numeral 22.
  • Radiation falling on the cathode 8 causes the liberation of electrons which are accelerated toward the periphery of the cylindrical anode 17 along approximately diametral paths leaving at right angles to the cathode surface 12. Since the anode 17 is permeable, the electrons will pass therethrough into the eld-free interior thereof. If the magnetic field were not present, these electrons would travel in straight, diametral paths across the tube With no Velocity change within the field-free space. Upon departure, however, from the anode, they do experience the decelerating field of the diametrically opposite dynode 5. However, because of the deflecting effect of the magnetic field 22, the electrons follow approximately circular paths indicated by the numeral 23 and will approach instead the dynode 2.
  • the strength of the magnetic field developed by the solenoid 20 may be altered. Proper deflection of the electron streams may thereby be controlled by adjusting this field strength such that substantially all of the electrons emitted by one dynode will impact the next succeeding dynode.
  • the plurality of ejected secondaries travel across the tube and impact the next succeeding dynode.
  • Each of these electrons ejects secondaries which repeat the cycle to the next dynode.
  • the number of electrons finally reaching the collector 9 is multiplied many times over the original emission from the cathode 8.
  • the stream of electrons initially emitted by the cathode 8 flow within the crossed pattern envelope indicated by numeral 25 to the dynode 2.
  • the secondaries emitted by the dynode 2 flow in a stream indicated by the crossed pattern 26, which terminates on the dynode 3. This pattern is repeated with the secondaries in each instance flowing in the same general pattern to the next succeeding dynode until eventually the collector 9 is reached.
  • variable emission energy which is present in all cases in all electron multipliers.
  • the present invention minimizes the effect of this variable emission energy by accelerating all electrons to high velocity, as established by the comparatively high potential (2000 v. as an example) on anode 17, in combination with the close proximity of anode 17 to the emitting surfaces.
  • the transit time spread pertaining to two electrons emitted with slightly different energies from a dynode is reduced by the ratio, LDAV/LVA, where LDA is the path length in the comparatively small gap between the emitting dynode or cathode and the anode 17, L is the total path length to the next dynode or collector, V is the potential difference between the emitting and collecting dynodes, and VA is the potential difference between the emitting dynode and the anode 17.
  • LDA is the path length in the comparatively small gap between the emitting dynode or cathode and the anode 17
  • L is the total path length to the next dynode or collector
  • V is the potential difference between the emitting and collecting dynodes
  • VA is the potential difference between the emitting dynode and the anode 17.
  • a further consequence of the coaxial cylindrical geometry is the fact that all electrons travel through essentially identical electric and magnetic fields, regardless of their point of origin on the emitting dynode. This advantageous property helps maintain the desired equal transit time of the electrons traveling to the subsequent dynode. As a consequence, higher currents with reduced transit time spread are achieved.
  • the graph in FIG. 5 in which the solid line curve is used to indicate the frequency response of a typical prior art tube and the dashed line curve the response of the present invention.
  • the present invention enables etiicient tube operation at higher frequencies than has heretofore been possible.
  • photocathode 8 has been disclosed as the initial electron emitter, it will be obvious to a person skilled in the art that other sources of electrons may be used. Also, initiating electrons need not originate at the circumference of the tube geometry, but instead can be directed inwardly from an electron gun axially of the tube to a point near the tube center at which an inclined dynode or deecting electrode may be positioned from which the electrons may be directed radially outwardly against the first dynode 2.
  • a further modification would be the replacement of the coaxial cylindrical geometry specifically shown in FIG. 4 with concentric spherical geometry, in which all electrodes are segments of spheres instead of cylinders. The geometrical relationship shown in FIGS. 1-3 would be unaffected by this change. Other obvious alternatives will appear to persons skilled in rthe art.
  • An electron multiplier comprising a series of dynodes having electron-multiplying surfaces circularly arranged in spaced relation about a common central axis, said dynode surfaces facing radially inwardly and being intersected by a plane including said axis, means for accelerating and directing electrons between facing said surfaces in a pattern of succession to cause electrons emitted from one said surface to flow to a successive surface displaced circumferentially from a diametrically opposed position, said means including a circular electron permeable anode coaxially disposed within said dynodes in the path of electrons passing therethrough between said successive surfaces and means for applying successively higher potential to said successive surfaces, respectively, and means for collecting electrons leaving the surface of highest potential.
  • said multiplier of claim 4 in which said member is a conductive screen, said accelerating and directing means further including means for providing a magnetic field coaxially of said member to deflect the electrons into following curved paths within said eld-free space toward said circumferentially displaced surfaces, the electron paths between said dynodes describing a pattern resembling a hypocycloid.
  • said magnetic eld means includes a solenoid coaxially surrounding said dynodes, said dynodes and said member being contained within an evacuated envelope.

Landscapes

  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
  • Common Detailed Techniques For Electron Tubes Or Discharge Tubes (AREA)
US599004A 1966-03-02 1966-12-05 Circular electron multiplier and permeable anode Expired - Lifetime US3454809A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US53123266A 1966-03-02 1966-03-02
US59900466A 1966-12-05 1966-12-05

Publications (1)

Publication Number Publication Date
US3454809A true US3454809A (en) 1969-07-08

Family

ID=24397798

Family Applications (1)

Application Number Title Priority Date Filing Date
US599004A Expired - Lifetime US3454809A (en) 1966-03-02 1966-12-05 Circular electron multiplier and permeable anode

Country Status (3)

Country Link
US (1) US3454809A (fr)
FR (1) FR93774E (fr)
GB (1) GB1202075A (fr)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1714406A (en) * 1923-07-30 1929-05-21 Raytheon Inc Method and apparatus for causing electrical conduction
US2150573A (en) * 1936-01-31 1939-03-14 Rca Corp Electric discharge device
US2231676A (en) * 1936-12-05 1941-02-11 Klangfilm Gmbh Electric amplifier
US2290775A (en) * 1940-05-01 1942-07-21 Rca Corp Stabilization of photoelectric electron multipliers
US2307035A (en) * 1936-05-27 1943-01-05 Gabor Dennis Electron multiplier
US2548225A (en) * 1948-09-17 1951-04-10 Rca Corp Method of and means for generating and/or controlling electrical energy
US3271699A (en) * 1963-07-19 1966-09-06 Litton Systems Inc Balanced modulator having the anode of a multiplier phototube directly connected to the cathode of the modulator tube

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1714406A (en) * 1923-07-30 1929-05-21 Raytheon Inc Method and apparatus for causing electrical conduction
US2150573A (en) * 1936-01-31 1939-03-14 Rca Corp Electric discharge device
US2307035A (en) * 1936-05-27 1943-01-05 Gabor Dennis Electron multiplier
US2231676A (en) * 1936-12-05 1941-02-11 Klangfilm Gmbh Electric amplifier
US2290775A (en) * 1940-05-01 1942-07-21 Rca Corp Stabilization of photoelectric electron multipliers
US2548225A (en) * 1948-09-17 1951-04-10 Rca Corp Method of and means for generating and/or controlling electrical energy
US3271699A (en) * 1963-07-19 1966-09-06 Litton Systems Inc Balanced modulator having the anode of a multiplier phototube directly connected to the cathode of the modulator tube

Also Published As

Publication number Publication date
GB1202075A (en) 1970-08-12
FR93774E (fr) 1969-05-16

Similar Documents

Publication Publication Date Title
US3128408A (en) Electron multiplier
US3374380A (en) Apparatus for suppression of ion feedback in electron multipliers
US3260876A (en) Image intensifier secondary emissive matrix internally coated to form a converging lens
US2138928A (en) Electron discharge device
US3798478A (en) Multibeam cathode ray tube having a common beam limiting aperture therein
US3243628A (en) Electron multiplier with curved resistive secondary emissive coating
US2214019A (en) Electronic switching device
US3702951A (en) Electrostatic collector for charged particles
US3936697A (en) Charged particle beam scanning device
US2163966A (en) Box element multiplier
US3718836A (en) Multipactor ion generator
US3454809A (en) Circular electron multiplier and permeable anode
US2721287A (en) Multiple beam gun
US2176221A (en) Electron discharge apparatus
US3235765A (en) Electron multiplier having an inclined field
US3016474A (en) Cathode ray tubes
US2753484A (en) Signal indicating device
US2806163A (en) Triple gun for color television
US2921212A (en) Gun system comprising an ion trap
US2726348A (en) Multiple beam gun
US2935642A (en) Electron gun
US2231682A (en) Electron multiplier
US2652512A (en) Electron gun
US2733365A (en) hoagland
US3849644A (en) Electron discharge device having ellipsoid-shaped electrode surfaces

Legal Events

Date Code Title Description
AS Assignment

Owner name: ITT CORPORATION

Free format text: CHANGE OF NAME;ASSIGNOR:INTERNATIONAL TELEPHONE AND TELEGRAPH CORPORATION;REEL/FRAME:004389/0606

Effective date: 19831122