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WO1990004852A1 - Source d'excitation de plasma a electrode creuse - Google Patents

Source d'excitation de plasma a electrode creuse Download PDF

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Publication number
WO1990004852A1
WO1990004852A1 PCT/US1989/004708 US8904708W WO9004852A1 WO 1990004852 A1 WO1990004852 A1 WO 1990004852A1 US 8904708 W US8904708 W US 8904708W WO 9004852 A1 WO9004852 A1 WO 9004852A1
Authority
WO
WIPO (PCT)
Prior art keywords
electrode
furnace
glow discharge
sample substance
enclosure
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.)
Ceased
Application number
PCT/US1989/004708
Other languages
English (en)
Inventor
Nathan E. Ballou
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.)
Battelle Memorial Institute Inc
Original Assignee
Battelle Memorial Institute Inc
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
Application filed by Battelle Memorial Institute Inc filed Critical Battelle Memorial Institute Inc
Publication of WO1990004852A1 publication Critical patent/WO1990004852A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • 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
    • H01J49/12—Ion sources; Ion guns using an arc discharge, e.g. of the duoplasmatron type

Definitions

  • the present invention relates to a hollow electrode plasma excitation source and particularly to such a source wherein the hollow electrode comprises an anode having a relatively positive voltage supplied thereto, and within which is received a centrally disposed cathode.
  • an enclosure is provided with a gas at reduced pressure which is adapted to serve as a plasma medium.
  • a first hollow electrode positioned within the enclosure, has a relatively positive d.c. potential applied thereto, while a second electrode within the first electrode receives a relatively negative d.c. potential.
  • the first, hollow electrode is formed of graphite or a refractory metal and is heated by passing a current therethrough, elevating the same in temperature for vaporizing a sample placed within the electrode. The sample is vaporized, and excited by the plasma produced between the first and second electrodes, whereby radiation is emitted which is a characteristic of the sample.
  • FIG. 1 is a schematic representation of a combined plasma source and furnace according to the present invention
  • FIG. 2 is an end view of the FIG. 1 apparatus
  • FIGS. 3 and 3A are respectively more detailed perspective and rear views of the plasma source and furnace
  • FIG. 4 is a schematic representation of another embodiment according to the present invention.
  • a source of gas communicates to housing 12 by way of valve 16 and it provides a noble gas (e.g. argon or helium) , ' hydrogen, or mixtures of noble gas and hydrogen at pressures in the range of a fraction of a Torr to tens of Torr.
  • a gas exit (not shown) can also be provided for the chamber.
  • the furnace 10 suitably takes the form of a right circular cylinder having a pair of "wings" 18 and 20 integrally joined to sides thereof at 180° spaced locations, through which current from an a.c. source is supplied to the cylinder.
  • the furnace 10 may be brought to temperatures on the order of 1,000-2,500°C.
  • furnace 10 in accordance with the present invention is utilized as an anode, i.e., positive electrode, of the plasma excitation source, while an elongated central electrode 24, suitably a graphite rod positioned substantially coaxially within cylindrical furnace 10, comprises the cathode or negative electrode.
  • furnace 10 and electrode 24 are connected respectively to the positive and negative terminals of d.c. power supply 26 for supplying a voltage of between approximately 200 volts d.c. and 2000 volts d.c. to establish a glow discharge primarily between the electrodes in the gas within enclosure 12, the gas serving as a plasma medium.
  • the power supply 26 is activated, the gas within the furnace 10 is ionized and specifically a negative glow region is established around cathode electrode 24.
  • the substance 22 to be analyzed is brought to a high temperature through activation of the furnace power supply and substance 22 is vaporized into the negative glow region.
  • the glow region may be viewed by an echelle polychromator 28 through a sapphire window 30 disposed in one wall of vacuum housing 12.
  • An annular image of the glow region is focused on the slit of the polychromator by means of an intermediately placed calcium fluoride lens 32.
  • the frequencies of radiation emitted in the glow region are indicative of elements in the sample 22, as sample 22 is vaporized and passes into the ionized region of the discharge.
  • the discharge generates excited states of sample atoms causing emissions that can be measured.
  • the furnace 10 has been described as formed of graphite and may comprise pyrolytically coated graphite, or may be formed of some other refractive metal.
  • the electrode 24 may similarly comprise a material such as pyrolytically coated graphite or tungsten wire.
  • FIGS. 3 and 3A illustrate the internal construction of the apparatus in greater detail.
  • a vacuum flange 34 supports a furnace assembly on two horizontally mounted high- current, copper feed-through conductors 36 and 38 which pass through the flange cover via insulating bushings.
  • the flange locates the furnace assembly within a vacuum housing suitably consisting of a six-way stainless steel cross (not shown) having appropriate flanges on the six ports and generally corresponding to housing 12 in FIG. 1. This arrangement allows the furnace components to be assembled or repaired outside the vacuum housing simply by removing flange 34.
  • the central electrode 24 in this instance was a slender rod of graphite, analogous to a pencil lead, embedded in member 56.
  • the electrode 24 is received through a bore in member 56, but is unsupported where it extends through furnace 10.
  • a conductor 60 which may comprise a spring or the like, contacts electrode 24 and passes downwardly through member 56 for making connection with an intermediate conductor leading to a supply such as supply 26 in FIG. 1.
  • furnace 10 was 1.9 cm long having an inside diameter of 0.4 cm.
  • the slender graphite rod 24 had a diameter 0.05 cm.
  • the plasma was easy to ignite and stable, and accurate analytical results were produced. Intensity measurements were repeated approximately 56 times a second with a polychromator viewing the glow region through a sapphire window in a flange cover of the vacuum housing (not shown) positioned for viewing the open end of furnace 10 in FIG. 3 opposite member 56.
  • FIG. 4 schematically illustrates a hollow electrode plasma apparatus according to the present invention employed as an ion source for mass spectrometry.
  • a sample for analysis is preferably vaporized and constituent atoms of the vapor are ionized by means of a plasma generated in a gas stream.
  • the ions in the gas stream are transported from the ion source through a gas skimmer located in a wall of the apparatus housing and into a mass spectrometer for measurement.
  • hollow electrode 10' which desirably comprises a vaporization furnace, is centrally positioned within a first chamber 70 of an elongate housing 12' at one end of which is supplied a source of flowing gas via entrance port 72.
  • the gas flowing into the enclosure can be noble gas (e.g. argon or helium), hydrogen, or mixtures of noble gas and hydrogen.
  • the pressure level within chamber 70 is low, on the order of approximately one Torr.
  • the tubular electrode 10' is connected to a positive voltage relative to coaxial central rod electrode 24' which is connected to a negative voltage such that the voltage difference between electrodes 10' and 24' is in the approximate range of 200 volts to 2,000 volts d.c.
  • the ion stream passes into a second chamber 78 and through an einzel lens 80 acting to focus the ion stream at the end aperture of skimmer cone 82 disposed between chamber 78 and chamber 84 wherein mass spectrometer means, as represented by plates 86, is located.
  • the cone 82 is located at the chamber exit partially to separate the gas from the ions generated in the plasma and which travel through the hole at the apex of the cone.
  • Chamber 78 is suitably maintained at a vacuum of approximately 10 Torr, being evacuated through port 88, while chamber 84 is desirably maintained at a vacuum of 10 to 10 Torr via port 90.
  • a second einzel lens 92 is utilized for directing the ion beam toward the mass spectrometer apparatus which may comprise either a magnetic sector or a quadrupole mass spectrometer used for ion separation and measurement.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Investigating, Analyzing Materials By Fluorescence Or Luminescence (AREA)
  • Other Investigation Or Analysis Of Materials By Electrical Means (AREA)

Abstract

Une source de plasma comprend un four (10) en tant qu'anode creuse à l'intérieur de laquelle est disposée une cathode coaxiale (24). La source est placée dans un logement (12) contenant un gaz ionisable de sorte qu'une décharge luminescente se produit entre l'anode et la cathode. Un rayonnement ou émission ionique résultant d'une décharge luminescente caractérise un échantillon placé dans le four et chauffé à des températures élevées.
PCT/US1989/004708 1988-10-27 1989-10-24 Source d'excitation de plasma a electrode creuse Ceased WO1990004852A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US26306388A 1988-10-27 1988-10-27
US263,063 1988-10-27

Publications (1)

Publication Number Publication Date
WO1990004852A1 true WO1990004852A1 (fr) 1990-05-03

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1989/004708 Ceased WO1990004852A1 (fr) 1988-10-27 1989-10-24 Source d'excitation de plasma a electrode creuse

Country Status (2)

Country Link
CA (1) CA2001237A1 (fr)
WO (1) WO1990004852A1 (fr)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1321548C (zh) * 2004-12-28 2007-06-13 西北师范大学 接触辉光放电等离子体发生装置
CN110505745A (zh) * 2014-01-31 2019-11-26 巨石材料公司 等离子体炬的设计
US11866589B2 (en) 2014-01-30 2024-01-09 Monolith Materials, Inc. System for high temperature chemical processing
US11926743B2 (en) 2017-03-08 2024-03-12 Monolith Materials, Inc. Systems and methods of making carbon particles with thermal transfer gas
US11939477B2 (en) 2014-01-30 2024-03-26 Monolith Materials, Inc. High temperature heat integration method of making carbon black
US11998886B2 (en) 2015-02-03 2024-06-04 Monolith Materials, Inc. Regenerative cooling method and apparatus
US12012515B2 (en) 2016-04-29 2024-06-18 Monolith Materials, Inc. Torch stinger method and apparatus
US12030776B2 (en) 2017-08-28 2024-07-09 Monolith Materials, Inc. Systems and methods for particle generation
US12119133B2 (en) 2015-09-09 2024-10-15 Monolith Materials, Inc. Circular few layer graphene
US12250764B2 (en) 2015-07-29 2025-03-11 Monolith Materials, Inc. DC plasma torch electrical power design method and apparatus
US12286540B2 (en) 2015-02-03 2025-04-29 Monolith Materials, Inc. Carbon black generating system
US12378124B2 (en) 2017-08-28 2025-08-05 Monolith Materials, Inc. Particle systems and methods
US12497517B1 (en) 2024-07-19 2025-12-16 Monolith Materials, Inc. Method of making carbon black

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3685911A (en) * 1968-06-17 1972-08-22 Applied Res Lab Capillary arc plasma source for and method of spectrochemical analysis
EP0140005A2 (fr) * 1983-09-10 1985-05-08 Firma Carl Zeiss Appareil pour produire un plasma avec un rayonnement plus intense dans la region des rayons X

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3685911A (en) * 1968-06-17 1972-08-22 Applied Res Lab Capillary arc plasma source for and method of spectrochemical analysis
EP0140005A2 (fr) * 1983-09-10 1985-05-08 Firma Carl Zeiss Appareil pour produire un plasma avec un rayonnement plus intense dans la region des rayons X

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Analytical Chemistry, Volume 59, No. 20, 15 October 1987, American Chemical Society, (Washington, DC, US), A. SCHEELINE et al.: "Direct Solids Elemental Analysis: Pulsed Plasma Sources", see pages 1185A-1196A *

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1321548C (zh) * 2004-12-28 2007-06-13 西北师范大学 接触辉光放电等离子体发生装置
US11866589B2 (en) 2014-01-30 2024-01-09 Monolith Materials, Inc. System for high temperature chemical processing
US11939477B2 (en) 2014-01-30 2024-03-26 Monolith Materials, Inc. High temperature heat integration method of making carbon black
US12144099B2 (en) 2014-01-31 2024-11-12 Monolith Materials, Inc. Plasma torch design
CN110505745A (zh) * 2014-01-31 2019-11-26 巨石材料公司 等离子体炬的设计
US12286540B2 (en) 2015-02-03 2025-04-29 Monolith Materials, Inc. Carbon black generating system
US11998886B2 (en) 2015-02-03 2024-06-04 Monolith Materials, Inc. Regenerative cooling method and apparatus
US12250764B2 (en) 2015-07-29 2025-03-11 Monolith Materials, Inc. DC plasma torch electrical power design method and apparatus
US12119133B2 (en) 2015-09-09 2024-10-15 Monolith Materials, Inc. Circular few layer graphene
US12012515B2 (en) 2016-04-29 2024-06-18 Monolith Materials, Inc. Torch stinger method and apparatus
US11926743B2 (en) 2017-03-08 2024-03-12 Monolith Materials, Inc. Systems and methods of making carbon particles with thermal transfer gas
US12030776B2 (en) 2017-08-28 2024-07-09 Monolith Materials, Inc. Systems and methods for particle generation
US12378124B2 (en) 2017-08-28 2025-08-05 Monolith Materials, Inc. Particle systems and methods
US12497517B1 (en) 2024-07-19 2025-12-16 Monolith Materials, Inc. Method of making carbon black

Also Published As

Publication number Publication date
CA2001237A1 (fr) 1990-04-27

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