US2231691A - Electron multiplier - Google Patents

Electron multiplier Download PDF

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Publication number
US2231691A
US2231691A US177286A US17728637A US2231691A US 2231691 A US2231691 A US 2231691A US 177286 A US177286 A US 177286A US 17728637 A US17728637 A US 17728637A US 2231691 A US2231691 A US 2231691A
Authority
US
United States
Prior art keywords
electrode
electron
ions
electrodes
multiplying
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
US177286A
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English (en)
Inventor
Jr Richard L Snyder
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.)
RCA Corp
Original Assignee
RCA 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
Priority to BE430852D priority Critical patent/BE430852A/xx
Application filed by RCA Corp filed Critical RCA Corp
Priority to US177286A priority patent/US2231691A/en
Priority to US171916A priority patent/US2231682A/en
Priority to FR845191D priority patent/FR845191A/fr
Priority to NL90376A priority patent/NL57028C/xx
Priority to GB31156/38A priority patent/GB520117A/en
Priority to CH206023D priority patent/CH206023A/de
Application granted granted Critical
Publication of US2231691A publication Critical patent/US2231691A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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

  • My invention relates to electric discharge tubes, particularly to electron multipliers, and has special reference to the provision of improvements in multi-stage electron multipliers Wherein the electron stream may 4be of such intensity as to initiate a disturbing iiow of ions in the residual gas.
  • an object of my invention is to provide an electrostatic type electron multiplier the operation of which is characterized by substantial freedom from those spurious internal electrical and electro-mechanical vibrations Whichuconstitute or give rise to tube noise.
  • Another object of my invention is to achieve a, noise-free electrostatic type electron multiplier without any sacrice in the efliciency or change in contour of the electron focusing elds.
  • Another object of my invention is to provide an electron multiplier wherein dark current (i. e., current Which flows when the tube is energized but the cathode not illuminated) is substantially obviated.
  • dark current i. e., current Which flows when the tube is energized but the cathode not illuminated
  • Figure 1 is a longitudinal sectional view of an electron multiplier constructed in accordance with the principle of the invention
  • Figure 2 is a cross-sectional view taken on the line 2-2 of Fig. 1, and
  • Figure 3 is a top plan View of the device of Fig. 1.
  • T designates a highly evacuated envelope which is preferably, though not necessarily, in the form of a cylindrical glass tube having a long central axis indicated by the dotted line :0.
  • the envelope or tube T is provided with a press P which is preferably circular, whereby it may accommodate several (12 in this case) electrode leads L without undue crowding. If desired, these leads L may be rigid enough and strong enough to support the electrodes to which they are connected. However, in this case, a number of disc-like spacers D, provided with springs S, which contact the inner wall of the tube, contribute to the support of the latter described electrode assembly.
  • the several leads L are preferably provided with insulation such, for example, as pieces of glass tubing G, of small diameter, which extend through the discs D to prevent short-circuiting.
  • the discs or spacers D are cut away adjacent their central portions and provide a support for an insulating frame F, which comprises upper and lower strips F1, F2, respectively, of glass or the like, which are maintained in spaced relation as by end-pieces F3, F4 of similar insulating material.
  • the rigid insulating strips F1, F2 are of undulate formation, the undulations of each strip being uniformly spaced along the axis or median line :1: with the convex sections of one strip drectly opposite the concave sections of the 0p- DOSite strip. Seated within each undulate con- Electrode I is a photosensitive cathode.
  • cave section of the frame F is a curved electronemissive electrode plate; those on the lower strip F2 are numbered I, 3, 5, 1, 9 and II, and those on the upper strip 2, 4, 6, 8, I0 and I2.
  • a return bend portion I1' which is of foraminous construction to permit light from an external source, exemplified in Fig. 1 by the lamp Y and lens Z, to impinge upon the photosensitive surface of the cathode section Ip.
  • 'I'he intermediate electrodes 2 to II inclusive are the multiplying electrodes. They are formed, for eX- ample, of silver suitably coated with a substance which is the equivalent of caesium, to render them capable of a copious flow of secondary electrons.
  • the electrode nearest press P is the electron collecting electrode, or anode; it is here shown in the form of an inclined imperforate plate I2 supported at the top by a curved plate I2a (which is conveniently similar to electrodes I to II), whose edge extends slightly beyond the inclined collecting surface.
  • Electrodes I to II inclusive are preferably of L-shape contour and, as described in the Rajchman and Pike disclosure, have their long legs m inclined toward the cathode with the transverse terminal edges of these long legs extending to, or slightly beyond, equally spaced points along the central axis :c of the tube.
  • the short legs n of these L-shaped electrodes extend in the general direction of the collector electrode or anode I2 and terminate at points removed substantially equal distances from the said axis m.
  • the long leg m of each L-shaped multiplying electrode thus extends beyond the short leg n of the next preceding L-shaped electrode of the same set.
  • This construction intensifies the electrostatic eld in the cup of the next preceding electrode of the same set and thereby provides a higher effective emission or saturation of the secondary electron emission from that electrode.
  • a further result of this construction is that the majority of the ions generated in the residual gas by the passage of the electron beam will be promptly arrested by the intruding long legs m of the multiplying electrodes. Thus, the majority of the ions generated in the space between the multiplying electrode Il and the anode I2 will be collected by the long legs m of electrodes I l and I0.
  • the contour and general arrangement of the electrodesabove described are similar in most respects to that of the Rajchman and Pike disclosure.
  • the insulating frame and its support are within the purview of the present invention.
  • the disc-like members D serve not only as elements of a non-microphonic support for the electrode assembly, but also serve to prevent the llow of ions which may escape through the open sides of the electrode assembly.
  • the discs serve in two ways to prevent the ow of ions.
  • the present invention contemplates the use of one or more pairs of auxiliary conductive elements or baliles in the space be- .tween each of the side edges of the conduit and the inner wall of the tube.
  • baliles d1J d2, d3 are provided. Asl shown, these elements may be supported upon, and electrically connected to, the correspondingly numbered discs D. They are further connected, respectively, to an adjacent multiplying electrode in either the top or bottom set. Thus, as more clearly shown in Fig. 2, elements d1 are connected, as by short leads w, to both the bottom multiplying electrode 3 and to disc D1. Neither discs Dl nor part d1, however, contacts electrode 4 in the upper set, so that short circuiting is avoided.
  • Each -baffle d is preferably in the form of a bent metal strip having a part a which follows the contour of the long leg m of the multiplying electrode to which it is connected, to a point adjacent its transverse edge, and a part b which bends backwardly (i. e., in the general direction of the anode) and toward the transverse edge of the next preceding (in point of electron travel) multiplying electrode in the opposite upper or lower) set.
  • each baille Since each baille is connected (by short leads w) to a multiplying electrode, the bent part b of each baille will project an electric field or surface into the space about the side edges of the electrode assembly, and the potential on this virtual surface will be the same at every point as that on the electrode to which the baiiies are connected.
  • baflies may be provided for each pair (upper and lower) of multiplying electrodes. It would needlessly complicate the drawing to show such modification.
  • An electric discharge device comprising an evacuated envelope containing a small amount of residual gas in which ions may be generated, said envelope having a long axis, a. cathode and an anode mounted adjacent opposite ends of said axis, a plurality of sets of multiplying electrodes mounted on opposite sides of said axis intermediate the cathode and anode, the side edges of said multiplying electrodes defining an open sided electron conduit from which ions may escape when said residual gas is bombarded by electrons from said cathode and multiplying electrodes, and means disposed adjacent the open sides of said electron conduit and extending into the space intermediate said conduit and the inner wall of said envelope for barring the passagey of said escaped ions.
  • An electric discharge device comprising an evacuated envelope having a long axis, a cathode and an anode mounted adjacent opposite ends of said axis, multiplying electrodes mounted on opposite sides of said axis between said cathode and anode, said electrodes constituting an open sided electrode assembly, and a conductor mounted exterior of said assembly ⁇ and extending across Aan open side thereof and connected to one of said multiplying electrodes, said conductor having a contour which corresponds substantially to the contour of the equipotential line projected, when the device is energized, from the electrode to which it is connected.
  • An electric discharge device comprising an open sided electrode assembly mounted within an evacuated envelope, said envelope containing a residual gas in which ions may be generated when the device is energized, a disc disposed intermediate the ends of said electrode assembly and supported adjacent its periphery on the inner wall of said envelope, said discvhaving a central aperture which extends substantially across said envelope and in which said electrode assembly is supported,l and a pair of bailies supported on opposite sides of said disc between the wall of said envelope and the open sides of said electrode assembly, said baliles and the surface of said disc constituting a barrier to the passage of said ions.
  • battles are connected to a common electrode and serve to extend the electric field about said electrode, when said device is energized, beyond the open sides of said electrode assembly.

Landscapes

  • Electron Tubes For Measurement (AREA)
  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
  • Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
US177286A 1937-11-30 1937-11-30 Electron multiplier Expired - Lifetime US2231691A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
BE430852D BE430852A (enrdf_load_stackoverflow) 1937-11-30
US177286A US2231691A (en) 1937-11-30 1937-11-30 Electron multiplier
US171916A US2231682A (en) 1937-11-30 1937-11-30 Electron multiplier
FR845191D FR845191A (fr) 1937-11-30 1938-10-26 Perfectionnements aux multiplicateurs d'électrons
NL90376A NL57028C (enrdf_load_stackoverflow) 1937-11-30 1938-10-26
GB31156/38A GB520117A (en) 1937-11-30 1938-10-27 Improvements in or relating to electron multipliers
CH206023D CH206023A (de) 1937-11-30 1938-10-28 Elektronenvervielfacher.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US177286A US2231691A (en) 1937-11-30 1937-11-30 Electron multiplier
US171916A US2231682A (en) 1937-11-30 1937-11-30 Electron multiplier

Publications (1)

Publication Number Publication Date
US2231691A true US2231691A (en) 1941-02-11

Family

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Family Applications (2)

Application Number Title Priority Date Filing Date
US177286A Expired - Lifetime US2231691A (en) 1937-11-30 1937-11-30 Electron multiplier
US171916A Expired - Lifetime US2231682A (en) 1937-11-30 1937-11-30 Electron multiplier

Family Applications After (1)

Application Number Title Priority Date Filing Date
US171916A Expired - Lifetime US2231682A (en) 1937-11-30 1937-11-30 Electron multiplier

Country Status (6)

Country Link
US (2) US2231691A (enrdf_load_stackoverflow)
BE (1) BE430852A (enrdf_load_stackoverflow)
CH (1) CH206023A (enrdf_load_stackoverflow)
FR (1) FR845191A (enrdf_load_stackoverflow)
GB (1) GB520117A (enrdf_load_stackoverflow)
NL (1) NL57028C (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2796546A (en) * 1953-06-29 1957-06-18 Chromatic Television Lab Inc Damp rod construction for cathode ray tube grid structure
US2983845A (en) * 1959-05-07 1961-05-09 Bendix Corp Electron multiplier spurious noise baffle
US4142123A (en) * 1977-02-10 1979-02-27 Rca Corporation Image display device with optical feedback to cathode
US4182968A (en) * 1976-04-23 1980-01-08 Rca Corporation Electron multiplier with ion bombardment shields

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2664515A (en) * 1951-06-22 1953-12-29 Lincoln G Smith Magnetic electron multiplier
DE1022703B (de) * 1952-10-23 1958-01-16 Fernseh Gmbh Elektrostatischer Sekundaerelektronenvervielfacher

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2796546A (en) * 1953-06-29 1957-06-18 Chromatic Television Lab Inc Damp rod construction for cathode ray tube grid structure
US2983845A (en) * 1959-05-07 1961-05-09 Bendix Corp Electron multiplier spurious noise baffle
US4182968A (en) * 1976-04-23 1980-01-08 Rca Corporation Electron multiplier with ion bombardment shields
US4142123A (en) * 1977-02-10 1979-02-27 Rca Corporation Image display device with optical feedback to cathode

Also Published As

Publication number Publication date
NL57028C (enrdf_load_stackoverflow) 1946-03-15
US2231682A (en) 1941-02-11
CH206023A (de) 1939-07-15
BE430852A (enrdf_load_stackoverflow)
GB520117A (en) 1940-04-15
FR845191A (fr) 1939-08-14

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