US3569756A - Ion source having a plasma and gridlike electrode - Google Patents

Ion source having a plasma and gridlike electrode Download PDF

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Publication number
US3569756A
US3569756A US649543A US3569756DA US3569756A US 3569756 A US3569756 A US 3569756A US 649543 A US649543 A US 649543A US 3569756D A US3569756D A US 3569756DA US 3569756 A US3569756 A US 3569756A
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electrode
gridlike
plasma
ion
ion source
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US649543A
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English (en)
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Otto Reifenschweiler
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US Philips Corp
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US Philips Corp
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H3/00—Production or acceleration of neutral particle beams, e.g. molecular or atomic beams
    • H05H3/06—Generating neutron beams
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J27/00—Ion beam tubes
    • H01J27/02—Ion sources; Ion guns
    • H01J27/16—Ion sources; Ion guns using high-frequency excitation, e.g. microwave excitation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J49/00—Particle spectrometers or separator tubes
    • H01J49/02—Details
    • H01J49/10—Ion sources; Ion guns
    • H01J49/105—Ion sources; Ion guns using high-frequency excitation, e.g. microwave excitation, Inductively Coupled Plasma [ICP]

Definitions

  • Trifari ABSTRACT An ion source employing; a plasma and a gridlike electrode forming part of the wall of a space in which ions are produced, the ions being accelerated by an accelerating electrode having an aperture the diameter of which is at least equal to half the diameter of the gridlike electrode and the resistance thereof to gas flow is so low that the pressure on each side is equal and so low that the ion flow is saturated.
  • the gridlike electrode has an aperture of at least 1 mm. in diameter through which electrons accelerated against the ion flow may be collected in the plasma space.
  • This application is a continuation of application Ser. No. 480,416, filed Aug. 17, 1965 and now abandoned.
  • This invention relates to ion sources intended especially for nuclear physical apparatus, such as a neutron generator, in which the ions are accelerated from a gridlike electrode forming part of the wall of a space in which ions are produced, by means of an extraction electrode having a single aperture.
  • the pressure 'drop was still a factor of 20 to 40.
  • the mass spectrometer was replaced by an ion-collector electrode in a high-capacity pump system.
  • the ion flow in known arrangements already is saturated if the voltage betweenthe grid and the extraction electrode is approximately 200 volts. For this reason subsequent acceleration is-necessary to obtain-the comparatively high ionic velocities such as are required in a mass spectrometer; A high voltage between the grid in the wall of the discharge space and the extraction electrode would be impossible in view of the high pressure prevailing.
  • Ion sources are also known in which the ions are extracted from a high-frequency plasma through an aperture in the wall surrounding the plasma which does not contain a grid.
  • a plasma boundary which fulfills the function of an emitter surface for the ions is thus formed by the action of the field of the extraction electrode which is in the form of a more or less long channel.
  • a difficulty involved in this arrangement- is that the plasma boundary depends as to shape and position upon the field of the extraction electrode and also upon the intensity of the ion flow relative to the densityof the plasma.
  • the variations in shape and position of the plasma boundary act upon the focusing of the ion beam, while instabilities may arise if the plasma boundary penetrates too far into the ionization space.
  • the upper limit of the voltage between the plasma and the extraction electrode is approximately kv. Subsequent acceleration is always necessary since in nuclear physical apparatus, such as, for example, neutron generators, accelerating voltages of approximately 150 kv. are frequently desirable.
  • Known constructions also invariably operate with a pressure drop and a pump.
  • An object of the invention is to provide an ion source which affords advantages with respect to known constructions.
  • ions are accelerated from a gridlike electrode which forms part of the wall of a space in which ions are produced, by means of an extraction electrode.
  • This electrode has a single aperture, the diameter of which is at least equal to half the diameter of the gridlike electrode and the resistance thereof to gas flow is so low that the pressure at each side is equal and so low that the ion flow is saturated at the accelerating voltage used which is upwards of kv.
  • the gridlike elec trode has a central aperture of at least 1 mm in diameter through which electrons accelerated against the ion flow may be collected in the plasma space.
  • the gridlike electrode may heat dissipation of the said grid may thus have a favorable value.
  • the extraction electrode houses a braking electrode for the electrons produced by the ions substantially on the ion-collector electrode so that these electrons cannot be accelerated in the opposite direction.
  • FIG. 1 is a cross-sectional view of an ion source according to the invention.
  • FIGS. 2a and 2b show respectively in cross section and plan view an enlarged view of the grid.
  • the ion source shown in FIG. 1 includes a glass cylinder enclosing a space in which a discharge plasma is formed by means of high-frequency discharge generated in hydrogen or in a mixture of hydrogen and its isotopes at a pressure of 0.01 mm.
  • the lower end of the glass cylinder 1 is partly closed by a spherical segment cap 2 of molybdenum having a diameter of approximately 15 mms.
  • the cap 2 has seven bores as seen in FIG. 2b each 3.5 mm. in diameter, the central bore being designated 3.
  • An extraction electrode 5 having an inlet aperture 6 is positioned opposite the gridlike electrode 2 and the rounded portion 4 is located externally thereof.
  • the extraction electrode extends downwards in a metallic cylinder 7 whichforms part of the wall of the vacuum space.
  • the latter merges into a glass cylinder 8 which houses a braking electrode 9 provided with a connector 10.
  • the ion-collector electrode is designated 11 and the boundary of the ion beam is shown in broken lines at 12. Any electrons accelerated through the aperture 3 to the discharge space despite the presence of the braking electrode are collected on a metal plate 13.
  • the accelerating voltage is applied between a connecting pin 14 which terminates in the conducting discharge plasma, and the accelerating electrode 5.
  • the electrode 2 and the pin 14 are at the same potential due to the presence of the conducting plasma.
  • An ion source comprising a vessel housing an ionizable medium in one portion thereof and having a wall constituted by a gridlike electrode communicating with a second portion of said vessel and constituting a plasma boundary when said ionizable medium is converted to a plasma by a high-frequency discharge, an extraction electrode within said latter portion for accelerating ions produced therein, said extraction electrode having an aperture the diameter of which is at least ,equal to half the diameter of the gridlike electrode and the resistance to gas flow is so low that the pressure on each side thereof is equal and so that the ion flow is saturated with an accelerating potential applied to said extraction electrode of at least 20 kilovolts, said gridlike electrode having a central aperture at least 1 mm in diameter whereby electrons accelerated counter to the ion flow may be collected in the other portion of the vessel.
  • An ion source as claimed in claim 1 in which the extraction electrode houses a braking electrode for the electrons produced within the ion-collector electrode.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Plasma & Fusion (AREA)
  • Combustion & Propulsion (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Analytical Chemistry (AREA)
  • Electron Sources, Ion Sources (AREA)
US649543A 1964-08-18 1967-06-28 Ion source having a plasma and gridlike electrode Expired - Lifetime US3569756A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL646409478A NL144087B (nl) 1964-08-18 1964-08-18 Ionenbron.

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US3569756A true US3569756A (en) 1971-03-09

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US649543A Expired - Lifetime US3569756A (en) 1964-08-18 1967-06-28 Ion source having a plasma and gridlike electrode

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US (1) US3569756A (pt)
DE (1) DE1303276B (pt)
GB (1) GB1062168A (pt)
NL (1) NL144087B (pt)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4155093A (en) * 1977-08-12 1979-05-15 Dennison Manufacturing Company Method and apparatus for generating charged particles
US4160257A (en) * 1978-07-17 1979-07-03 Dennison Manufacturing Company Three electrode system in the generation of electrostatic images
US4507588A (en) * 1983-02-28 1985-03-26 Board Of Trustees Operating Michigan State University Ion generating apparatus and method for the use thereof
US4587430A (en) * 1983-02-10 1986-05-06 Mission Research Corporation Ion implantation source and device
EP0362944A1 (fr) * 1988-10-07 1990-04-11 Societe Anonyme D'etudes Et Realisations Nucleaires - Sodern Dispositif d'extraction et d'accélération des ions dans un tube neutronique scellé à haut flux avec adjonction d'une électrode auxiliaire de préaccélération
EP0362946A1 (fr) * 1988-10-07 1990-04-11 Societe Anonyme D'etudes Et Realisations Nucleaires - Sodern Dispositif d'extraction et d'accélération des ions limitant la réaccélération des électrons secondaires dans un tube neutronique scellé à haut flux
US4996017A (en) * 1982-03-01 1991-02-26 Halliburton Logging Services Inc. Neutron generator tube
US5078950A (en) * 1988-10-07 1992-01-07 U.S. Philips Corporation Neutron tube comprising a multi-cell ion source with magnetic confinement
WO1995012883A1 (en) * 1993-11-01 1995-05-11 Eneco, Inc. Glow discharge apparatus and methods providing prerequisites and testing for nuclear reactions

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2538267A (en) * 1945-05-19 1951-01-16 Bell Telephone Labor Inc Gaseous electron discharge device
US2570124A (en) * 1949-10-20 1951-10-02 Rca Corp Positive ion beam gun
US2856532A (en) * 1955-06-16 1958-10-14 Eugene F Martina Pulsed ion source
US2985760A (en) * 1958-09-12 1961-05-23 High Voltage Engineering Corp Compact neutron source

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2538267A (en) * 1945-05-19 1951-01-16 Bell Telephone Labor Inc Gaseous electron discharge device
US2570124A (en) * 1949-10-20 1951-10-02 Rca Corp Positive ion beam gun
US2856532A (en) * 1955-06-16 1958-10-14 Eugene F Martina Pulsed ion source
US2985760A (en) * 1958-09-12 1961-05-23 High Voltage Engineering Corp Compact neutron source

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
I. O. Reifenschweiler et al., A NEW PRINCIPLE OF ION EXTRACTION FROM A GAS DISCHARGE Plasma, NUCLEAR INSTRUMENTS AND METHODS 30 (1964) pp. 298 302 *

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4155093A (en) * 1977-08-12 1979-05-15 Dennison Manufacturing Company Method and apparatus for generating charged particles
US4160257A (en) * 1978-07-17 1979-07-03 Dennison Manufacturing Company Three electrode system in the generation of electrostatic images
US4996017A (en) * 1982-03-01 1991-02-26 Halliburton Logging Services Inc. Neutron generator tube
US4587430A (en) * 1983-02-10 1986-05-06 Mission Research Corporation Ion implantation source and device
US4507588A (en) * 1983-02-28 1985-03-26 Board Of Trustees Operating Michigan State University Ion generating apparatus and method for the use thereof
EP0362944A1 (fr) * 1988-10-07 1990-04-11 Societe Anonyme D'etudes Et Realisations Nucleaires - Sodern Dispositif d'extraction et d'accélération des ions dans un tube neutronique scellé à haut flux avec adjonction d'une électrode auxiliaire de préaccélération
EP0362946A1 (fr) * 1988-10-07 1990-04-11 Societe Anonyme D'etudes Et Realisations Nucleaires - Sodern Dispositif d'extraction et d'accélération des ions limitant la réaccélération des électrons secondaires dans un tube neutronique scellé à haut flux
FR2637725A1 (fr) * 1988-10-07 1990-04-13 Sodern Dispositif d'extraction et d'acceleration des ions limitant la reacceleration des electrons secondaires dans un tube neutronique scelle a haut flux
FR2637723A1 (fr) * 1988-10-07 1990-04-13 Etiudes Realisations Nucleaire Dispositif d'extraction et d'acceleration des ions dans un tube neutronique scelle a haut flux avec adjonction d'une electrode auxiliaire de preacceleration
US5078950A (en) * 1988-10-07 1992-01-07 U.S. Philips Corporation Neutron tube comprising a multi-cell ion source with magnetic confinement
WO1995012883A1 (en) * 1993-11-01 1995-05-11 Eneco, Inc. Glow discharge apparatus and methods providing prerequisites and testing for nuclear reactions

Also Published As

Publication number Publication date
GB1062168A (en) 1967-03-15
DE1303276B (pt)
NL144087B (nl) 1974-11-15
NL6409478A (pt) 1966-02-21

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