Classifications

• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03F—AMPLIFIERS
  • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
  • H03F1/52—Circuit arrangements for protecting such amplifiers
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J27/00—Ion beam tubes
  • H01J27/02—Ion sources; Ion guns
  • H01J27/26—Ion sources; Ion guns using surface ionisation, e.g. field effect ion sources, thermionic ion sources
• • 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
  • H01J49/16—Ion sources; Ion guns using surface ionisation, e.g. field-, thermionic- or photo-emission
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03F—AMPLIFIERS
  • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
  • H03F3/04—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements with semiconductor devices only
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2913—Rod, strand, filament or fiber
  • Y10T428/2933—Coated or with bond, impregnation or core
  • Y10T428/294—Coated or with bond, impregnation or core including metal or compound thereof [excluding glass, ceramic and asbestos]
  • Y10T428/2942—Plural coatings
  • Y10T428/2949—Glass, ceramic or metal oxide in coating

Definitions

• the present invention is concerned with stabilized thermionic sources and their method of preparation.
• the thermionic sources according to the present invention are designed for use in mass spectrometry.
• the sources are prepared by coating a metallic heating filament with a layer of refractory substance possessing poor thermal conductivity.
• the coating preferably is carried out by depositing on the surface of the filament a layer of the refractory substance and calcining the structure thus obtained so as to adhere said layer to the filament.
• the resulting stabilized filament is then coated with a layer of a mixture comprising the product to be analyzed and the refractory substance.
• the filament is again calcined so as to produce an outer layer composed of the latter mixture. Titanium pyrophosphate, magnesium aluminate and nickel oxide have been found to be the preferable refractory substances.
• the invention has for its object a method of stabilization of a thermionic source which can be utilized in mass spectrometry and which makes it possible to obtain a constant thermionic emission.
• the method in accordance with the invention consists in depositing on a metallic filament which serves as a heating source a layer of substance which is capable of providing as a result of heating a uniform layer having a smooth surface, in effecting the slow calcination of the filament which is coated with said substance until there is formed a layer which effectively adheres to the filament, in charging the aggregate thus obtained with a mixture consisting of said substance and of the product to be analyzed by mass spectrometry and in calcining the aggregate.
• the thermionic source as thus prepared can be employed for the purpose of performing an analysis by mass spectrometry; said source consists of a heating filament which is coated with a layer of stabilizing substance which is in turn coated with a layer of a mixture of the stabilizing substance and of the substance to be analyzed.
• the stabilizer must be refractory and have poor thermal conductivity in order to withstand without melting the high temperatures to which the filament is brought at the time of heating.
• the stabilizer must be such that, after it has been applied on the filament and after said filament has been heated, said stabilizer is present in a uniform layer having a smooth surface.
• the stabilizing substance thus prepared is essentially intended for temperature stabilizatron.
• Titanium pyrophosphate TiP O- Magnesium aluminate (MgAl O Nickel oxide (NiO).
• salts are also suitable for the practical application of the invention. It is merely necessary to ensure that such salts meet the following conditions: they must be refractory, they must have poor thermal conductivity and they must provide, once they have been applied on the filament and heated, a uniform layer having a smooth surface.
• salts of calcium, strontium, barium, zirconium, thorium and hafnium can be mentioned by way of example the salts of calcium, strontium, barium, zirconium, thorium and hafnium.
• the metallic heating filament consists of a metal which has a high melting point and which can advantageously be platinum, rhenium or tungsten.
• the stabilizer is prepared in the form of gel and is deposited on the filament by means of a platinum spatula; the aggregate is then subjected to a first calcining treatment by sending an electric current through the filament, thus increasing its temperature by Joule effect.
• the heating must be performed with care in such a manner as to ensure that the layer of stabilizing substance effectively adheres to the filament after calcination.
• the filament which is thus covered with stabilizer is then charged with a layer of stabilizing substance which is mixed with the product to be analyzed.
• the quantities employed must be small since it would prove undesirable to overcharge the filament.
• the calcination is then performed under the same conditions as before.
• the filament appears in the form of a thin layer of stabilizer which adheres to the metal in a perfect manner and the thickness of which can vary between 0.2 and 1 mm. but is preferably equal to 0.5 mm. Under the microscope, the surface of said layer is of uniform appearance although not glass-like.
• the source then remains stable throughout the analysis (this latter can last several hours) without any appreciable decrease in.the ion current.
• a thermionic source in accordance with the invention has the great advantage, in particular when performing an analysis by mass spectrometry, in that the product to be analyzed can be utilized in solid form, thus requiring only a minimum number of manipulations. Moreover, a source of this kind makes it possible to perform isotopic analyses of long duration without any fluctuations which are higher than those produced by a gas source.
• a method for producing a stabilized thermionic source designed for use in mass spectrometry which method comprises the steps of:
• a method according to claim 1 wherein said substance is selected from the group consisting of titanium pyrophosphate, magnesium aluminate and nickel oxide.
• a thermionic source designed for use in mass spectrometery which comprises a heating filament composed of a conductive substance having a high melting point coated with a uniform layer of a refractory substance having poor thermal conductivity and additionally coated with a layer comprising a mixture of the product to be analyzed by mass spectrometry and said refractory substance.
• a thermionic source according to claim 3 wherein said refractory substance is selected from the group consisting of titanium pyrophosphate, magnesium aluminate and nickel oxide.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Power Engineering (AREA)
• Physics & Mathematics (AREA)
• Plasma & Fusion (AREA)
• Analytical Chemistry (AREA)
• Combustion & Propulsion (AREA)
• Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
• Sampling And Sample Adjustment (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=8826561

Family Applications (1)

Country Status (10)

Cited By (1)

Families Citing this family (4)

Citations (3)

• 1964
  • 1964-03-27 FR FR968985A patent/FR1398135A/fr not_active Expired
• 1965
  • 1965-03-15 CH CH357365A patent/CH432054A/fr unknown
  • 1965-03-17 DE DEC35339A patent/DE1297899B/de active Pending
  • 1965-03-17 BE BE661230A patent/BE661230A/fr unknown
  • 1965-03-19 GB GB11756/65A patent/GB1088268A/en not_active Expired
  • 1965-03-22 IL IL23192A patent/IL23192A/en unknown
  • 1965-03-25 LU LU48259A patent/LU48259A1/fr unknown
  • 1965-03-25 US US442773A patent/US3423583A/en not_active Expired - Lifetime
  • 1965-03-26 SE SE395065A patent/SE220542C1/sv unknown
  • 1965-03-29 NL NL6503985A patent/NL6503985A/nl unknown

Patent Citations (3)

Also Published As

Similar Documents