US2969480A - Ion sources - Google Patents

Ion sources Download PDF

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Publication number
US2969480A
US2969480A US809828A US80982859A US2969480A US 2969480 A US2969480 A US 2969480A US 809828 A US809828 A US 809828A US 80982859 A US80982859 A US 80982859A US 2969480 A US2969480 A US 2969480A
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United States
Prior art keywords
tube
bulb
conductor
plate
high frequency
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Expired - Lifetime
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US809828A
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English (en)
Inventor
Klein Siegfried
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Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
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Commissariat a lEnergie Atomique CEA
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    • 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

Definitions

  • the present invention relates to ion sources, that is to say to devices for producing beams of ionized particles for use in various apparatus for the treatment of such particles, such as particle accelerators, mass spectrometers, isotopic separation systems.
  • the invention is more especially concerned with ion sources in which ionization of the particles is obtained by applying a Ihigh frequency electric eld to a chamber, generally made of quartz or glass (in particularvof an aluminum and sodium borosilicate sold under the trademark Pyrex).
  • the high frequency electric field serving to produce ionization is generally obtained in circuits having distributed constants and the ionic yields are low in comparison to the high frequency power brought into play, this being due to the fact that, for a high frequency circuit having distributed constants, the coefficient Q is low and the losses are high.
  • the object of the present invention is to provide ⁇ an ion source intended in particular to ionize gases (such as hydrogen, deuterium, helium, nitrogen) or vapors (for instance vapors of light metals, such as lithium or sodium) to form a beam of ionized particles intended to be fed to a particle accelerator, with a high ionic yield (averaging some ten milliammeters for a high frequency power of approximately 75 watts).
  • gases such as hydrogen, deuterium, helium, nitrogen
  • vapors for instance vapors of light metals, such as lithium or sodium
  • such an ion source comprises a tube, generally made of glass or quartz, means for producing a high vacuum in said tube, means for applying a high direct potential difference between the two ends of said tube, means for feeding to one end of said tube a substance in the gaseous form to be ionized, and a high frequency current source
  • the characteristic feature of this invention consists in the fact that it comprises a resonating cavity energized by said source and producing in a restricted zone thereof a very concentrated electric eld, said tube comprising, in the vicinity of its other end, an enlarged portion in the form of a flat bulb extending transversely to the direction of the bulb, said bulb being disposed in said restricted zone.
  • Fig. 1 is a sectional View of said embodiment of the invention.
  • Fig. 2 shows the electric lay-out of the ion source of Fig. 1,
  • Fig. 3 diagrammatically shows the resonating cavity of the ion source of Fig. 1 and the manner in which said cavity is energized.
  • Fig. 4 illustrates the distributed constant resonating circuit used for energizing the resonating cavity of Fig. 3.
  • the ion source proper (Fig. l) comprises a tube 1, generally made of Pyrex glass or quartz, said tube having, near one of its ends 24, an enlarged portion in the form of a fiat bulb 2 extending transversely to the direction of the tube, said bulb being of relatively small dimension, for instance having a volume of about one cubic centimeter.
  • the end 24 of tube 1 is supported by a sleeve 3 carried by a conical piece 4 maintained in a housing 25a of a conductor wall 2S.
  • Pieces 3 and 4 are made of metals capable of resisting the impact of ions, such as platinum, stainless steel, aluminum.
  • ⁇ sleeve 3 is made of platinum and piece 4 of aluminum.
  • the other end 26 of tube 1 is of conical shape and carries the device T for feeding the gas or vapor to be ionized.
  • This device includes a chamber 27 with two hollow extensions 28 and 29, extension 28 fitting on the end 26 of tube land extension 29 holding a hollow electrode 5 through which is introduced, in the direction of arrow F, the gas or vapor to be ionized.
  • Chamber 27 contains a quartz disc 30 intended to increase the disruptive voltage of the gaseous medium inside the ion source.
  • tube 1 is housed in a coaxial resonating cavity R which comprises the following elements:
  • a conductor envelope 6 coaxial with said central conductor 7 and located at a distance therefrom;
  • a metal plate 34 located at the other end of envelope 6 and welded at 30a thereto, said plate 34 being rigid with a sleeve 35 xed on conductor 7;
  • Toroidal rubber joints 32 and 33 are inserted between plate 8 and bulb 2 on the one hand, and between said plate 8 and wall 25 on the other hand;
  • Pumping means communicate with the space 50 between plates 8 and 25 and located on the inside of toroidal joint 33 so as to maintain, through the horrins 4a of piece 4, a vacuum ranging from 10-3 to 10-4 mm. of mercury in tube 1.
  • a high frequency voltage is applied to the central conductor 7 of the resonating cavity from an oscillator tube 9 (located in a shielding casing 23) in the following manner: the elements of said oscillator tube 9 (as will be more completely described hereinafter) are connected through conductors 37, 44 and 43, extending through said shielding casing 23, to the upper conducting plates of three capacitors 12, 16 and 18.
  • the under conducting plates of said capacitors are respectively connected, through copper rods 20, 21 and 22, to different points of the central conductor 7.
  • a single sheet of mica 36 of a thickness of about 0.1 mm., forms the dielectric between the respective plates of the three capacitors 12, 16 and 18. In this way, there is obtained a capacitive coupling between the resonating cavity and the oscillator, which permits of imparting very high potentials thereto.
  • the casing 23 of the high frequency source is grounded.
  • the oscillator tube 9 is for instance a tetrode calcu. lated to consume about -100 watts at a frequency averaging mHz., this tube being fed with a plate high voltage -I-HTl applied to plate 11 through line 10, with a screen high voltage -l-HT2 applied to screen grid 14 through line 13 and with a heating voltage applied to cathode 38 through wires 39, current return taking place through the common line 19 which constitutes the negative terminal -HT ofthe feed high voltages.
  • Choke accesso coils 40 prevent return flow of the high frequency currents produced by tube 9, and capacitors 41, 42 prevent the ow of direct current directly toward line 19.
  • the control grid 15 of tube 9 is connected on the' one lia-nd directly to conductor 43 lead-ing to capacitor 16 and on the other hand, through a resistance 17 of some thousands of ohms, to conductor 44 leading to capacitor 18 which is connected, through conductor 44a, to the return line 19, that is to say to the cathode from the high frequency viewpoint. Finally, the plate voltage is applied, through conductor 37, to capacitor 12.
  • tube 9 cooperates with resonating cavity R to form an oscillating system as diagrammatically illustrated by Fig. 3.
  • the concentration of the lines of force 46a of the electric eld in a restricted zone S of the resonating cavity where, according to the essential feature of the invention, is located the ionization zone constituted by bulb 2, ensures a high ionization of the gas or vapor placed in said bulb. Furthermore, due to the fact that the Q factor of a resonating cavity may be very high for very high frequencies (in opposition to what takes place in distributed constant resonating circuits), it .is possible to start the ionization of the gas or vaporun bulb 2 very easily because the eld is very intensive in this volume before ionization is started. It is thus possible to obtain, with a chamber according to the invention, a Q coecient averaging 1000, which ensures a very easy starting of ionization.
  • ionization zone (bulb 2) is contiguous to the extraction zone, extraction taking place through known means, for instance by means of a series of extraction, acceleration and focussing electrodes (for instance of the type described in the article published in. the number of December 1948 of the periodical, The Review of Scientiiic Instruments, pages 907-909), to direct the ions toward the accelerator or other device making use of these ions.
  • An ion source which comprises, in combination, a tube, means for applying a high direct potential difference between the ends of said tube, said tube having, near one of its ends, an enlarged portion in the form of a flat bulb extending transversely to the direction of said tube, pumping means for exhausting said tube, means for feeding the other end of said tube with a gaseous substance to be ionized, a high frequency current source and means forming a resonating cavity at least a portion of which surrounds said bulb, said cavity being coupled with said source to be energized by it and being arranged to form a zone of concentrated electric field including, and substantially limited to, the volume of said bulb.
  • An ion source which comprises, in combination, a tube, means for applying a high direct potential difference between the ends of said tube, said tube having, near one of its ends, an enlarged portion in the form of a flat bulb extending transversely to the direction of said tube, pumping means for exhausting said tube, means for feeding the other end of said tube with a gaseous substance to be ionized, a resonating cavity constituted by a hollow central conductor closely surrounding said tube from said second mentioned end thereof to said bulb, a conductor casing surrounding said central conductor coaxially thereto and at a distance therefrom, a transverse conductor plate rigid and in electric contact with said central conductor at a point thereof remote from said bulb and located on the same side thereof as said second mentioned end of said tube, said plate being in electric contact with one end of said envelope, a transverse conductor plate rigid and in electric contact with the other end of said envelope extending on the other side of said bulb from said first mentioned plate at a distance from said bulb just a little greater than the thickness
  • An ion source according to claim l including a capacitive coupling between said high frequency current source and said resonating cavity.
  • An ion source according to claim l including a capacitive coupling between said high frequency current source and said resonating cavity and a grounded shield casing surrounding said last mentioned source.
  • An ion source which comprises, in combination, a tube, means for applying a high direct potential difference between the ends of said tube, said tube having, near one of its ends, an enlarged portion in the form of a flat bulb extending transversely to the direction of said tube, pumping means for exhausting said tube, means for feeding the other end of said tube with a gaseous substance to be ionized, a resonating cavity constituted by a hollow central conductor closely surrounding said tube from said second mentioned end thereof to said bulb, a conductor casing surrounding said central conductor coaxially thereto and at a distance therefrom, a transverse conductor plate rigid and in electric contact with said central conductor at a point thereof remote from said bulb and located on the same side thereof as said second mentioned end of said tube, said plate being in electric contact with one end of said envelope, a transverse conductor plate rigid and in electric contact with the other end of said envelope extending on the other side of said bulb from said first mentioned plate at a distance from said bulb just a little greater than the thickness

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
  • Electron Tubes For Measurement (AREA)
  • Electron Sources, Ion Sources (AREA)
  • Particle Accelerators (AREA)
US809828A 1958-05-03 1959-04-29 Ion sources Expired - Lifetime US2969480A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR764698 1958-05-03
FR767110A FR73679E (fr) 1958-05-03 1958-06-04 Nouvelle source d'ions

Publications (1)

Publication Number Publication Date
US2969480A true US2969480A (en) 1961-01-24

Family

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US809828A Expired - Lifetime US2969480A (en) 1958-05-03 1959-04-29 Ion sources
US817758A Expired - Lifetime US2977495A (en) 1958-05-03 1959-06-03 Ion source

Family Applications After (1)

Application Number Title Priority Date Filing Date
US817758A Expired - Lifetime US2977495A (en) 1958-05-03 1959-06-03 Ion source

Country Status (6)

Country Link
US (2) US2969480A (fr)
CH (2) CH354173A (fr)
DE (2) DE1179309B (fr)
FR (2) FR1209092A (fr)
GB (2) GB882366A (fr)
LU (2) LU37149A1 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3263415A (en) * 1961-03-06 1966-08-02 Aerojet General Co Ion propulsion device
US3265918A (en) * 1961-12-11 1966-08-09 High Voltage Engineering Corp Ion source having plasma control means
US3312727A (en) * 1965-02-03 1967-04-04 Dow Corning Organosilicon compounds
US4087720A (en) * 1975-10-08 1978-05-02 Sharp Kabushiki Kaisha Multi-beam, multi-aperture ion sources of the beam-plasma type
FR2416545A1 (fr) * 1978-02-03 1979-08-31 Thomson Csf Source d'ions produisant un flux dense d'ions de basse energie, et dispositif de traitement de surface comportant une telle source
US4240007A (en) * 1979-06-29 1980-12-16 International Business Machines Corporation Microchannel ion gun

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB902166A (en) * 1959-08-17 1962-07-25 Atomic Energy Authority Uk Improvements in or relating to mass spectrometers
US3353853A (en) * 1965-05-03 1967-11-21 James H Heywood Tube connecting fastener
US3462335A (en) * 1965-09-13 1969-08-19 Bell Telephone Labor Inc Bonding of thermoplastic composition with adhesives
US4994715A (en) * 1987-12-07 1991-02-19 The Regents Of The University Of California Plasma pinch system and method of using same
FR2639756B1 (fr) * 1988-11-30 1994-05-13 Centre Nal Recherc Scientifique Source de vapeurs et d'ions

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2633539A (en) * 1948-01-14 1953-03-31 Altar William Device for separating particles of different masses
US2817032A (en) * 1954-03-05 1957-12-17 Dwight W Batteau Gaseous-discharge method and system
US2826708A (en) * 1955-06-02 1958-03-11 Jr John S Foster Plasma generator
US2836750A (en) * 1955-01-07 1958-05-27 Licentia Gmbh Ion source
US2883580A (en) * 1956-07-13 1959-04-21 Wallace D Kilpatrick Pulsed ion source

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE527952A (fr) * 1953-04-10
US2883568A (en) * 1957-06-25 1959-04-21 Rca Corp Apparatus for producing thermallycool charged particles
US2880337A (en) * 1958-01-02 1959-03-31 Thompson Ramo Wooldridge Inc Particle acceleration method and apparatus
US2892114A (en) * 1958-05-06 1959-06-23 Wallace D Kilpatrick Continuous plasma generator

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2633539A (en) * 1948-01-14 1953-03-31 Altar William Device for separating particles of different masses
US2817032A (en) * 1954-03-05 1957-12-17 Dwight W Batteau Gaseous-discharge method and system
US2836750A (en) * 1955-01-07 1958-05-27 Licentia Gmbh Ion source
US2826708A (en) * 1955-06-02 1958-03-11 Jr John S Foster Plasma generator
US2883580A (en) * 1956-07-13 1959-04-21 Wallace D Kilpatrick Pulsed ion source

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3263415A (en) * 1961-03-06 1966-08-02 Aerojet General Co Ion propulsion device
US3265918A (en) * 1961-12-11 1966-08-09 High Voltage Engineering Corp Ion source having plasma control means
US3312727A (en) * 1965-02-03 1967-04-04 Dow Corning Organosilicon compounds
US4087720A (en) * 1975-10-08 1978-05-02 Sharp Kabushiki Kaisha Multi-beam, multi-aperture ion sources of the beam-plasma type
FR2416545A1 (fr) * 1978-02-03 1979-08-31 Thomson Csf Source d'ions produisant un flux dense d'ions de basse energie, et dispositif de traitement de surface comportant une telle source
US4240007A (en) * 1979-06-29 1980-12-16 International Business Machines Corporation Microchannel ion gun

Also Published As

Publication number Publication date
FR1209092A (fr) 1960-02-29
GB882367A (en) 1961-11-15
US2977495A (en) 1961-03-28
FR73679E (fr) 1960-09-05
CH354173A (fr) 1961-05-15
DE1190590B (de) 1965-04-08
GB882366A (en) 1961-11-15
CH354865A (fr) 1961-06-15
LU37242A1 (fr) 1960-11-28
LU37149A1 (fr) 1960-10-28
DE1179309B (de) 1964-10-08

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