US3395306A - Dynode structure for an electron multiplier device - Google Patents

Dynode structure for an electron multiplier device Download PDF

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Publication number
US3395306A
US3395306A US521108A US52110866A US3395306A US 3395306 A US3395306 A US 3395306A US 521108 A US521108 A US 521108A US 52110866 A US52110866 A US 52110866A US 3395306 A US3395306 A US 3395306A
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United States
Prior art keywords
dynode
slats
sheet
slat
apertures
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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
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US521108A
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English (en)
Inventor
Donald K Coles
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TDK Micronas GmbH
ITT Inc
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Deutsche ITT Industries GmbH
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Publication date
Application filed by Deutsche ITT Industries GmbH filed Critical Deutsche ITT Industries GmbH
Priority to US521108A priority Critical patent/US3395306A/en
Priority to GB0855/67A priority patent/GB1163451A/en
Priority to BE692634D priority patent/BE692634A/xx
Priority to NL6700691.A priority patent/NL165329C/xx
Application granted granted Critical
Publication of US3395306A publication Critical patent/US3395306A/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

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    • 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
    • H01J43/10—Dynodes

Definitions

  • An extended area dynode for an electron multiplier has a multiplicity of apertures formed of slatted elements separated by ribs to provide a self-supporting planar structure having a maximum electron emissive surface with a high degree of transmission through the apertures.
  • the present invention relates to electron multipliers and more particularly to improved extended area dynodes for both single-stage and multi-stage tubes.
  • a single-stage electron multiplier tube basically consists of a source of electrons, such as an electron gun or photocathode, a secondary emissive electrode, or dynode, and a collector electrode, or anode. These electrodes have potentials applied thereto which establish an electric field operative to cause impingement of primary electrons on the dynode and secondary electrons therefrom to be collected by the anode.
  • a multi-st-age electron multiplier provides a cascade of dynodes with successively higher potentials such that secondary electrons born in one dynode impinge on and are multiplied by the succeeding dynode.
  • an electron multiplier Among the several desiderata of an electron multiplier are the reduction of cost, reduction of electron transit time, and compactness of structure.
  • the ability of a multistage tube to carry greater currents may be enhanced by closer spacing between dynodes, this permitting the use of higher values of axial field strength for a given potential difference between dynodes.
  • the multiplier should be capable of high-speed operation; the time of response to an input signal is limited by the trajectory between the electron source and the anode, and in multistage tubes by the dynode spacing. Time-resolution capability and time-distortion of input pulses are of importance in some applications, such as when the multiplier is used in conjunction with a wide bandwidth optical communication system.
  • One method by which time-resolution may be improved is the use of a fine structure of apertures in the dynodes, so that consecutive dynodes may be placed close together.
  • Enhancement of the operation of a multiplier tube with respect to the above-mentioned considerations may be obtained merely by taking a given tube and making it proportionately physically smaller.
  • the venetian blind type of dynode has many advantages over other structures and will be more fully described below, but in the known designs a small slat size leads to mechanical weakness and lack of rigidity. For tubes of fairly large diameter, slats of the desired small size cannot be constructed without an unacceptable loss of dimensional stability.
  • the Weiss form of dynode is so designed in an attempt to overcome this limitation by utilizing a fine-mesh screen of round wires woven together.
  • a primary object of the present invention is to provide a dynode structure for an electron multiplier tube which is of fine mesh size, mechanically strong in relation to its size, and requires no mechanical support except at its edges.
  • the slat elements are of a size which renders them relatively stiff and self-supporting, the sizes and number of the rib portions being adequate to hold the slat elements in fixed position relative to each other whereby the dynode element is rendered self-supporting while presenting forwardly a maximum degree of electron-emitting surface for a given total degree of openness.
  • FIG. 1 is a front-end view of a single-stage electron multiplier tube embodying one form of a dynode according to the present invention
  • FIG. 3 is an enlarged, fragmentary front view of a portion of the dynode of FIGS. 1 and 3;
  • FIG. 4a is a section taken substantially along section line 44 of FIG. 3;
  • FIG. 4b is a section like FIG. 4a but showing a slightly different embodiment of this invention.
  • FIG. 5 is a fragmentary front view, like FIG. 3, of another embodiment of this invention.
  • FIG. 6 is a sectional view taken substantially along section line 6--6 of FIG. 5;
  • FIG. 7 is a sectional view taken substantially along section line 7-7 of FIG. 5;
  • FIG. 9 is a cross-section taken substantially along section line 99 of FIG. 8.
  • FIG. 10 is a section taken along line 10-10 of FIG. 8.
  • an evacuated glass envelope 1 has a fiat window 2 provided on its inner surface with an extended area, substantially transparent photocathode 3.
  • a ring terminal 4 mounts the window 2 in the end of the tube and serves as an electrode for applying a potential to the photocathode 3.
  • An extended area, disc-like dynode, indicated generally by the numeral 5, is fixedly positioned in parallel spaced relation with respect to the window 2 and is secured around its circumference to a ring electrode 6, which extends through the envelope 1.
  • a fine wire mesh 7 of high electron-transmissivity and disc-like in shape is positioned a small distance in front of the dynode 5 and is clamped between, at the edges thereof, two conductive mounting rings 8 and 9.
  • the ring 8 conductively fixedly secures the dynode 5 to the electrode 6 and maintains the mesh 7 in parallel spaced relation with and at the same electrical potential as the dynode 5.
  • the advantages of using this mesh 7 are more fully described in US. Patent No. 2,871,368.
  • the electrons secondarily emitted by the dynode 5 are collected by a planar anode 10.
  • a conductive post 11 in the end of the envelope 1 serves both as mechanical support and electrical contact for the anode 10.
  • the preferred, dynode embodiment of this invention is easily and inexpensively manufactured from a thin sheet of beryllium-copper or silver-magnesium by stamping and forming.
  • the dynode configuration resembles a venetian blind in that it is provided with a multiplicity of elongated slats 12 arranged in parallel, spaced relation and also in columns, as indicated in FIG. 1 by the numerals 13, 14 and 15, respectively. Separating the columns are flat bands or rib portions 16 which are straight and parallel to each other.
  • the slats 12, as shown more clearly in FIG. 3, in the various rows are arranged in end-to-end relation and are fiat, as shown more clearly in FIG. 4a.
  • the slats are turned at an angle of from 35 to 60 with respect to the plane of the dynode as defined by the bands 16, this plane being positioned midway between the front and rear edges of the slats 12 as shown more clearly in FIG. 4a.
  • the spaces 17 between the individual slats 12 constitute the dynode apertures which admit primary electrons for impingement against the forwardly or cathode-facing surfaces of the slats 12 and permit the escape of the secondaries therefrom to the anode 10.
  • the dynode will present a sufiiciently strong and rigid structure so as to withstand the forces of the electric fields within the tube as well as ordinary shock and vibration.
  • the numeral 18 indicates the cathode side or front of the dynode.
  • the structure is somewhat transparent.
  • FIG. 417 wherein it is shown that the bands 16 are provided with V-shaped crimps 19 which move the adjacent slats 12 (of FIG. 4a) closer together. Moved sutficiently close together, the dynode will be opaque as viewed from about the position of the numeral 18a.
  • Typical, although not minimum, dimensions of such a dynode having a diameter of about two inches may be a sheet thickness of .002 inch, :1 slat spacing of .020 inch, a spacing between bands 16 of about .200 inch, a slat width of about .020 inch, and a slat angle of about 45 with respect to the plane of the bands 16.
  • the bands 16 may be reinforced (for instance, by welding a wire along the lengths thereof or by crimping them into a V-shape in cross-section), it has been found that the bands 16 alone provide more than adequate strength to prevent the slats 12 from bending. Both of the slat configurations of FIGS.
  • FIG. 4b presents the most. It will be noted that while this design provides a relatively opaque dynode facing the cathode, still relatively large apertures 17 for electrons to pass through the dynode are present. Both of the conditions of the large percentage of dynode area and the relatively large apertures lead to the achievement of a multiplier tube having a relatively high gain. Considering the operation of the dynode thus far described in connection with the tube of FIGS.
  • FIGS. 5 through 10 a second embodiment of this invention which may be fabricated from flat sheet stock the same as the dynode 5 of FIGS. 1 and 2.
  • the sheet stock is lanced along straight, interrupted lines identified by the numeral 21 which are spaced apart and parallel. Also, these cuts are staggered as shown to provide ribs or hands 16a correspondingly stepped.
  • This provides individual slats 22 in end-to-end relation spaced apart by the bands the individual slats being bent along parallel fold lines 23 and 24 as shown more clearly in FIGS. 5 and 6.
  • laterally adjacent slats 22, as indicated by the two numerals 22a and 22b are deliberately separated in parallelism to provide the elongated apertures 25 therebetween. As shown in FIG. 6, these apertures have approximately the shape of parallelograms.
  • the metal is displaced to a sufiicient extent that when the dynode is mounted in the tube of FIG. 2, the individual slats 22 will be set at an angle of approximately 45 with respect to a plane parallel to the cathode 3.
  • FIG. 7 indicates this angular relationship, the primary electrons travelling along the path 20a impacting the surface of one of the slats 22 and ejecting secondaries along the path of the arrow 26 toward the anode.
  • FIGS. 8, 9 and 10 A still further embodiment of this invention is illustrated in FIGS. 8, 9 and 10 which, in configuration corresponds substantially identically to so-called expanded metal.
  • a sheet 27 of metal is lanced along the lines 28 at spaced intervals and then expanded to provide the bent slats 29 which project both forwardly and rearwardly, as shown more clearly in FIGS. 9 and 10, from the intervening rib portions 30.
  • the rib portions 30 separate the spaces between the cuts 28 in the sheet metal.
  • the slats 29 are separated to provide apertures 31, of substantially diamond shape.
  • the dynode defines a general plane and the slats 29 are set at an angle of something in the order of 45 with respect to this plane.
  • Dynodes made according to this invention are of exceedingly fine mesh and thin dimension.
  • several dynodes may be stacked in an array in accordance with conventional practice and positioned quite closely together.
  • space charge limitations and electron transit times may be materially reduced, thereby permitting the development of output currents of appreciable proportions and rapid rise times.
  • a multiplier tube may be made smaller and more compact.
  • an extended area dynode comprising a planar sheet-like element having a multiplicity of apertures separated by reinforcing rib portions, said apertures being defined by a plurality of adjacent spaced slat elements having secondary emitting surfaces which face a common forward direction and extend transversely to the plane generally defined by said sheet-like element, said slat elements being elongated and arranged in end-to-end relation, said rib portions being interposed between the ends of adjacent slat elements and extending along the plane of said sheet-like element, said slat elements being of a size which renders them relatively stiff and self-supporting, the sizes and number of said rib portions being adequate to hold said slat elements in fixed position relative to each other, whereby said sheet-like element is rendered self-supporting while presenting forwardly a maximum area of secondary-emitting surface for a given total degree of transmission of secondary electrons through the apertures.
  • elongated portions of said slat elements are fiat and lie in parallel planes, said slat elements being arranged in a plurality of columns which are parallel to each other, said rib portions being elongated, spaced apart and parallel and extending at an acute angle with respect to the length dimensions of said slat elements, said rib portions defining planes which are parallel to each other and transverse to the planes of the elongated portions of said slat elements, the planes of both said rib portions and said elongated slat portions being transverse to the general plane of said sheet-like element.
  • the dynode of claim 1 in combination with a cathode and an anode, said cathode and anode being planar and in parallel spaced relation with respect to said sheetlike element, and said sheet-like element being disposed between said cathode and anode.

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  • Electron Tubes For Measurement (AREA)
  • Common Detailed Techniques For Electron Tubes Or Discharge Tubes (AREA)
US521108A 1966-01-17 1966-01-17 Dynode structure for an electron multiplier device Expired - Lifetime US3395306A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US521108A US3395306A (en) 1966-01-17 1966-01-17 Dynode structure for an electron multiplier device
GB0855/67A GB1163451A (en) 1966-01-17 1967-01-13 Improvements in Electron Multipliers
BE692634D BE692634A (da) 1966-01-17 1967-01-16
NL6700691.A NL165329C (nl) 1966-01-17 1967-01-17 Dynode voor een elektronenvermenigvuldiger.

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US521108A US3395306A (en) 1966-01-17 1966-01-17 Dynode structure for an electron multiplier device

Publications (1)

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US3395306A true US3395306A (en) 1968-07-30

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US (1) US3395306A (da)
BE (1) BE692634A (da)
GB (1) GB1163451A (da)
NL (1) NL165329C (da)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1422740A2 (de) * 2002-11-21 2004-05-26 Infineon Technologies AG Vorrichtung zum Erzeugen von Sekundärelektronen, insbesondere Sekundärelektrode und Beschleunigungselektrode

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2546663B1 (fr) * 1983-05-25 1985-07-12 Hyperelec Tube photomultiplicateur a une dynode insensible aux champs magnetiques eleves

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3039016A (en) * 1957-07-06 1962-06-12 Emi Ltd Electrodes
US3253182A (en) * 1961-11-03 1966-05-24 Philips Corp Slotted electrode for an electron multiplier tube

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3039016A (en) * 1957-07-06 1962-06-12 Emi Ltd Electrodes
US3253182A (en) * 1961-11-03 1966-05-24 Philips Corp Slotted electrode for an electron multiplier tube

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1422740A2 (de) * 2002-11-21 2004-05-26 Infineon Technologies AG Vorrichtung zum Erzeugen von Sekundärelektronen, insbesondere Sekundärelektrode und Beschleunigungselektrode
US20040104657A1 (en) * 2002-11-21 2004-06-03 Andreas Kyek Apparatus for producing secondary electrons, a secondary electrode, and an acceleration electrode
DE10254416A1 (de) * 2002-11-21 2004-06-09 Infineon Technologies Ag Vorrichtung zum Erzeugen von Sekundärelektronen, insbesondere Sekundärelektrode und Beschleunigungselektrode
EP1422740A3 (de) * 2002-11-21 2007-05-23 Infineon Technologies AG Vorrichtung zum Erzeugen von Sekundärelektronen, insbesondere Sekundärelektrode und Beschleunigungselektrode
US20080185952A1 (en) * 2002-11-21 2008-08-07 Infineon Technologies Ag Apparatus for Producing Secondary Electrons, a Secondary Electrode, and an Acceleration Electrode
US7417240B2 (en) 2002-11-21 2008-08-26 Infineon Technologies Ag Apparatus for producing secondary electrons, a secondary electrode, and an acceleration electrode
US7772572B2 (en) 2002-11-21 2010-08-10 Infineon Technologies Ag Apparatus for producing secondary electrons, a secondary electrode, and an acceleration electrode

Also Published As

Publication number Publication date
NL6700691A (da) 1967-07-18
BE692634A (da) 1967-07-17
GB1163451A (en) 1969-09-04
NL165329B (nl) 1980-10-15
NL165329C (nl) 1981-03-16

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Owner name: ITT CORPORATION

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

Effective date: 19831122