US3769537A - Baffle for perforated electrode in a crossed-field switch device - Google Patents

Baffle for perforated electrode in a crossed-field switch device Download PDF

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Publication number
US3769537A
US3769537A US00289195A US3769537DA US3769537A US 3769537 A US3769537 A US 3769537A US 00289195 A US00289195 A US 00289195A US 3769537D A US3769537D A US 3769537DA US 3769537 A US3769537 A US 3769537A
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United States
Prior art keywords
electrode
switch device
interelectrode space
anode
crossed
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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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US00289195A
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English (en)
Inventor
G Hofmann
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Raytheon Co
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Hughes Aircraft Co
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Publication date
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J31/00—Cathode ray tubes; Electron beam tubes
    • H01J31/02—Cathode ray tubes; Electron beam tubes having one or more output electrodes which may be impacted selectively by the ray or beam, and onto, from, or over which the ray or beam may be deflected or de-focused
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J17/00—Gas-filled discharge tubes with solid cathode
    • H01J17/02—Details
    • H01J17/14—Magnetic means for controlling the discharge

Definitions

  • ABSTRACT In the nonconducting state, breakdown between concentric electrodes is determined by the Paschen law. 11 the inner electrode which defines the interelectrode space is perforated, ionization can occur therein, thus reducing holdoff voltage at a given pressure. Path length-limiting shielding adjacent to the electrode perforations prevents ionization within the electrode to maintain holdoff voltage, corresponding to the original electrode spacing.
  • This invention is directed to a crossed field switch device, and particularly to path length-limiting baffling to control electron path length for control of the conditions under which cascading ionization will take place.
  • a circular or annular interelectrode space is provided.
  • the electron path is substantially circular through the annulus, and the electron path length in conjunction with the gas in the interelectrode space provides for cascading ionization, which in turn permits interelectrode electric conduction.
  • the electron path is radial and is too short for the cascading ionization.
  • a crossed field switch device which has at least one perforated electrode which defines the interelectrode space, and has a baffle in association with the perforations to limit the maximum electron path length in the absence of a magnetic field.
  • FIG. 1 is a perspective view, with parts broken away and parts shown in section, of a crossed field switch device constructed in accordance with this invention.
  • FIG. 2 is an enlarged perspective view ofa portion of the baffle construction employed in conjunction with the perforated electrode in the crossed field switch device.
  • FIG. 3 is a section taken generally along the line 33 of FIG. 2.
  • FIG. 4 is a transverse section through the crossed field switch device of FIG. 1.
  • FIG. 5 is a Paschen curve showing the conditions for conductivity in the interelectrode space.
  • the crossed field switch device of this invention is generally indicated at 10. It is serially connected with a DC electric supply 12 and a load 14. On and offswitching of the crossed field switch device 10 thus controls the flow of electric current from supply 12 through load 14.
  • crossed field switch device 10 comprises housing 16 which is carried upon bottom flange 18.
  • Bottom flange 18 is, in turn, mounted upon base flange 20.
  • the flanges are secured together, as by conventional nuts and bolts, to provide a tight seal.
  • Base flange 20 stands upon foot 22 for supporting the crossed field switch device structure.
  • F urthermore a vacuum connection can be connected to the bottom of foot 22 for controlling the pressure on the interior of housing 16 and controlling the type of gas within the housing. Hydrogen, including its isotope, is a satisfactory gas.
  • Housing 16, together with its base flange 20, serves as a suitable vacuum-tight envelope.
  • Cathode 24 is in the form of a cylindrical tube. It is spaced inwardly from housing 16.
  • the cathode 24 has a lower end closure 26. Stand-off 28 supports cathode 24 from lower flange 20. Lower end closure 26 does not need to effect closure, but simply provides mechanical support for the cathode and reduces plasma end losses. By this construction, the entire cathode can be withdrawn downwardly through the large opening in bottom flange 18, when flanges 18 and 20 are separated. By this means, inspection and service of the cathode, as well as inspection and service of the interior of housing 16, are accomplished.
  • Cathode 24 is metallic and can be made of stainless steel. Cathode 24 is electrically connected through its lower end closure 26 and stand-off 28 to flange 20. Therefore, electrical connection to the cathode can be made either directly through flange 20 or through foot 22.
  • Cathode 24 preferably has an axial slot to prevent the circumferential circulation of current during switching transients, when the axial
  • Anode 30 is of cylindrical tubular construction and is positioned concentrically within cathode 24 to provide a radial space 32.
  • the radial space 32 is substantially equal at all facing positions of the anode and cathode.
  • Housing 16 has a top cap 34 of electrically insulative material.
  • Anode 30 is carried on top end closure 36 which has a central mounting stud 38. Central mounting stud 38 extends through top cap 34 in vacuum-tight connection to provide an electrical connectionthrough the anode, as well as structural mounting for the anode.
  • Anode 30 has aplurality of holes or perforations 40 therethrough so that the interior space within hollow anode 30 is in communication with the interelectrode space 32.
  • the volume within the interior of anode 30 is thus in gas communication with the interelectrode space.
  • Magnet 42 is positioned on the exterior of housing 30 in such a manner as to provide magnetic lines of force in the interelectrode space 32 which are substantially parallel to the axis of the electrodes, at least over a substantial part of the electrode length.
  • Magnet 42 is illustrated as being an electromagnet, and such is preferred so that the magnetic field can be readily switched on and off.
  • the power supply to magnet 42 is preferably of such nature as to provide for rapid turnon and off of the field. Its strength is such as to provide a field between 25 and 150 gauss. Seventy gauss was found to be a preferred value, Considering the turnon and turnoff effects, as well as magnet power consumption.
  • the interior of anode 30, as well as the interelectrode space, is filled with a gas to an appropriate pressure.
  • the Paschen curve is shown therein. This curve illustrates conditions of conductivity in glow discharge through a gas.
  • the area above the curve of FIG. is a conductive region, while the area below and to the left, as well as below and to the right of the curve line is a nonconductive region.
  • the voltage V is the voltage applied to the interelectrode space. It is the electric field applied to the space.
  • the value of p is the gas pressure in the interelectrode space, while the value of d is the electron path length. When there is no magnetic field, d is equal to the interelectrode radial space.
  • the product pd where d is the electron path length, is in the conductive region of the Paschen curve.
  • baffle 44 In order to control the electron path length, in order to limit the electron path length so that there is not an extended path length d through the holes 40, baffle 44, see FIGS. 2 and 3, is provided.
  • Baffle 44 can be any type of construction which permits gas passage'from the interior of the anode out through holes 40 in the anode into the interelectrode space 32.
  • baffle 44 should limit the line-of-sight through the holes 40.
  • a plurality of supported rings is illustrated in FIGS. 1, 2, 3, and 4.
  • a plurality of axially spaced rings, two of which are indicated at 46 and 48, are positioned on the interior of anode 30.
  • the rings are of sufficient diameter that there is an annular space around the outside of these outer rings and interiorly of anode 32, see FIG. 4.
  • the rings are secured to posts standing through the interior thereof.
  • Four posts 50., 52, 54, and 56 are illustrated.
  • the outer rings are axially spaced along their mounting posts.
  • space 58 is seen between outer rings 46 and 48.
  • inside rings are provided to overlap the space.
  • inside rings 60 and 62 are shown as being axially spaced and axially positioned to overlap the spaces between the outer rings.
  • the inside rings are positioned interiorly of posts 50, 52, 54.,and 56 and are secured thereto.
  • baffle 44 is preferably of metallic material and is supported from the anode, at least at top end closure 36.
  • the baffie 44 is at anode potential.
  • the baffle thus limits the path length of electrons flowing in a radial direction, so that the product pd can be maintained low in the absence of a magnetic field. As seen in FIG. 5, this provides a high holdoff voltage.
  • either or both the inner or outer electrodes can be perforated. If the outer electrode is perforated so that the space between the outer electrode and the housing can also contribute gas to the interelectrode space, it is desirable to use baffles adjacent those perforations to also limit the straight line paths through the perforation. Similarly, in the structure shown in FIG. 1, the anode and the cathode can be reversed simply by reversing the potential. However, it is desirable to maintain the cathode area as large as possible. For this reason, the cathode is unperforated and is placed as the exterior electrode.
  • the switch device is constructed so that, in the end chambers at the ends of the electrodes, straight line electron paths are limited by close placement of adjacent structures or by insertion of floating electrodes or baffles.
  • first and second spaced electrodes defining an interelectrode space therebetween, gas in said interelectrode space and means for controllably applying a magnetic field to said interelectrode space so that, when an electric field is applied between said electrodes, glow discharge of electrode current conduction takes place in the interelectrode space between the electrodes when the magnetic field is above a critical value and does not take place when the magnetic field is below the critical value, said second electrode being perforated so that gas can move through the electrode perforations into the interelectrode space to aid in maintaing glow discharge, the improvement comprising:
  • baffle positioned adjacent said second electrode on the side of said second electrode away from said interelectrode space so as to not interfere with the glow discharge in the interelectrodespace and positioned adjacent said second electrode perforations to limit the length of the electron flow path, from the interelectrode space through said perforations.
  • said first and second electrodes are tubular and said interelectrode space is an annular space, said means for applying a magnetic field in the annular interelectrode space providing a field which is substantially parallel to the tubular axis.
  • first electrode is the outer tubular electrode and said second electrode is the inner tubular electrode, said first electrode being a cathode and said second electrode being an anode.
  • baffle comprises spaced rings positioned inside said perforated anode electrode.
  • inner rings are positioned interiorly of said posts and mounted on said posts and are positioned to overlap the spaces between said spaced electrodes.
  • the crossed field switch device of claim 7 further including a supply of electric potential and an electric load serially connected with said crossed field switch device so that offswitching of said crossed field switch device cuts off current flow from said supply through said electric load.

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  • Gas-Filled Discharge Tubes (AREA)
  • Physical Or Chemical Processes And Apparatus (AREA)
  • Lasers (AREA)
US00289195A 1972-09-14 1972-09-14 Baffle for perforated electrode in a crossed-field switch device Expired - Lifetime US3769537A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US28919572A 1972-09-14 1972-09-14

Publications (1)

Publication Number Publication Date
US3769537A true US3769537A (en) 1973-10-30

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US00289195A Expired - Lifetime US3769537A (en) 1972-09-14 1972-09-14 Baffle for perforated electrode in a crossed-field switch device

Country Status (11)

Country Link
US (1) US3769537A (ja)
JP (1) JPS54751B2 (ja)
AU (1) AU477142B2 (ja)
CA (1) CA999634A (ja)
CH (1) CH555594A (ja)
DE (1) DE2342084C3 (ja)
FR (1) FR2200611B1 (ja)
GB (1) GB1408810A (ja)
IT (1) IT1008036B (ja)
NL (1) NL156856B (ja)
SE (1) SE386305B (ja)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2819111A1 (de) * 1977-05-17 1978-11-23 Hughes Aircraft Co Gasentladungs-schaltroehre mit gekreuzten feldern und verfahren zum einschalten einer solchen schaltroehre
US6452315B1 (en) * 2000-02-08 2002-09-17 Ronald A. Vane Compact RF plasma device for cleaning electron microscopes and vacuum chambers
US20080017794A1 (en) * 2006-07-18 2008-01-24 Zyvex Corporation Coaxial ring ion trap
US20110017247A1 (en) * 2009-07-24 2011-01-27 Xei Scientific, Inc. Cleaning Device for Transmission Electron Microscopes
US20160131548A1 (en) * 2014-11-07 2016-05-12 Mks Instruments, Inc. Long lifetime cold cathode ionization vacuum gauge design
US10359332B2 (en) 2015-01-15 2019-07-23 Mks Instruments, Inc. Polymer composite vacuum components

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2572881A (en) * 1946-04-22 1951-10-30 Rothstein Jerome Thyratron cathode design to prevent cleanup of hydrogen
US2786956A (en) * 1954-08-19 1957-03-26 Gera Corp Adjustable baffle for gaseous discharge devices
CA700832A (en) * 1964-12-29 Menown Hugh Hydrogen thyratron switches
US3558960A (en) * 1968-11-27 1971-01-26 Hughes Aircraft Co Switching device
US3638061A (en) * 1970-07-15 1972-01-25 Hughes Aircraft Co Magnetically controlled crossed-field interrupter and switch tube with pressure control for long duration pules

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA700832A (en) * 1964-12-29 Menown Hugh Hydrogen thyratron switches
US2572881A (en) * 1946-04-22 1951-10-30 Rothstein Jerome Thyratron cathode design to prevent cleanup of hydrogen
US2786956A (en) * 1954-08-19 1957-03-26 Gera Corp Adjustable baffle for gaseous discharge devices
US3558960A (en) * 1968-11-27 1971-01-26 Hughes Aircraft Co Switching device
US3638061A (en) * 1970-07-15 1972-01-25 Hughes Aircraft Co Magnetically controlled crossed-field interrupter and switch tube with pressure control for long duration pules

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2819111A1 (de) * 1977-05-17 1978-11-23 Hughes Aircraft Co Gasentladungs-schaltroehre mit gekreuzten feldern und verfahren zum einschalten einer solchen schaltroehre
US6452315B1 (en) * 2000-02-08 2002-09-17 Ronald A. Vane Compact RF plasma device for cleaning electron microscopes and vacuum chambers
US20080017794A1 (en) * 2006-07-18 2008-01-24 Zyvex Corporation Coaxial ring ion trap
US20110017247A1 (en) * 2009-07-24 2011-01-27 Xei Scientific, Inc. Cleaning Device for Transmission Electron Microscopes
US8349125B2 (en) 2009-07-24 2013-01-08 Xei Scientific, Inc. Cleaning device for transmission electron microscopes
US20160131548A1 (en) * 2014-11-07 2016-05-12 Mks Instruments, Inc. Long lifetime cold cathode ionization vacuum gauge design
US9588004B2 (en) * 2014-11-07 2017-03-07 Mks Instruments, Inc. Long lifetime cold cathode ionization vacuum gauge design
US10359332B2 (en) 2015-01-15 2019-07-23 Mks Instruments, Inc. Polymer composite vacuum components
US10876917B2 (en) 2015-01-15 2020-12-29 Mks Instruments, Inc. Polymer composite vacuum components
US11366036B2 (en) 2015-01-15 2022-06-21 Mks Instruments, Inc. Polymer composite vacuum components

Also Published As

Publication number Publication date
DE2342084C3 (de) 1975-08-21
AU5926773A (en) 1975-02-20
IT1008036B (it) 1976-11-10
FR2200611B1 (ja) 1977-02-25
JPS54751B2 (ja) 1979-01-16
FR2200611A1 (ja) 1974-04-19
SE386305B (sv) 1976-08-02
GB1408810A (en) 1975-10-08
CH555594A (de) 1974-10-31
DE2342084A1 (de) 1974-03-28
CA999634A (en) 1976-11-09
DE2342084B2 (de) 1975-01-16
NL156856B (nl) 1978-05-16
AU477142B2 (en) 1976-10-14
NL7312745A (ja) 1974-03-18
JPS4969267A (ja) 1974-07-04

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