US3699381A - Ion source device having control means for reducing filament current below its starting value - Google Patents

Ion source device having control means for reducing filament current below its starting value Download PDF

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Publication number
US3699381A
US3699381A US105321A US3699381DA US3699381A US 3699381 A US3699381 A US 3699381A US 105321 A US105321 A US 105321A US 3699381D A US3699381D A US 3699381DA US 3699381 A US3699381 A US 3699381A
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United States
Prior art keywords
filament
current
intermediate electrode
anode
circuit
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US105321A
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Toshio Kondo
Hifumi Tamura
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Hitachi Ltd
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Hitachi Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J49/00—Particle spectrometers or separator tubes
    • H01J49/02—Details
    • H01J49/022—Circuit arrangements, e.g. for generating deviation currents or voltages ; Components associated with high voltage supply
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J27/00—Ion beam tubes
    • H01J27/02—Ion sources; Ion guns
    • H01J27/08—Ion sources; Ion guns using arc discharge
    • H01J27/10—Duoplasmatrons ; Duopigatrons
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/02—Details
    • H01J37/04—Arrangements of electrodes and associated parts for generating or controlling the discharge, e.g. electron-optical arrangement or ion-optical arrangement
    • H01J37/08—Ion sources; Ion guns
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/02—Details
    • H01J37/24—Circuit arrangements not adapted to a particular application of the tube and not otherwise provided for
    • H01J37/242—Filament heating power supply or regulation circuits
    • 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
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S315/00—Electric lamp and discharge devices: systems
    • Y10S315/05—Starting and operating circuit for fluorescent lamp

Definitions

  • This invention relates to an ion source device for an ion microanalyzer and the like and, more particularly, to an ion source device of the Duoplasmatron type having means for reducing the filament current during steady state operation thereof.
  • An object of this invention is to provide means for making it possible to reduce the steady filamentcurrent in an ion microanalyzer of the type described.
  • This invention is characterized in that a current reduction resistor is inserted in the filament heating circuit and switching means is arranged so as to short-circuit both terminals of the reduction resistor.
  • the switching means is energized by a current flowing through an intermediate electrode circuit which causes both terminals to open so that the filament current flows through the current reduction resistor and the steady state filament current for maintaining discharge is reduced.
  • FIG. I is a schematic circuit diagram indicating an I embodiment of this invention.
  • FIG. 2 shows the relationship between filament current and anode current in an ion source device.
  • a filament 2 is connected to a d. c. heating power source 1 which provides heater current thereto, and a d. c. accelerating voltage source 3 is connected between an intermediate electrode 4 and the filament 2 so as to accelerate electrons emitted from said filament.
  • a magnet 6 made Of ferrite is disposed between said intermediate electrode 4 and an anode 5 so as to insulate these elements and to concentrate the electrons in the space therebetween.
  • a gas having a constant quantity is supplied to a space adjacent to said intermediate electrode 4 by proper means (not shown) and ionized as a result of discharge occurring due to impingement v with said electrons.
  • An ion accelerating high voltage source 7 is connected between said anode 5 and an extractor 8 so that the ions are extracted therefrom by said extractor 8 and further are introduced into an ion microanalyzer (not shown) so that the ions are directed to a speciment in a known manner.
  • aresistor 9 is inserted in said intermediate electrode circuit.
  • Both secondary windings of the insulating transformers l0 and 11 are connected to the respective inputs of the power sources 1 and 3, and both primary windings thereof are connected to an a. 0. power source (not shown).
  • a current reduction resistor 13 and a relay 16 having an exciting coil 17 and a contact 18- are disposed in the system, in addition to the above-described elements.
  • the current reduction resistor 13 is inserted in the filament circuit 12
  • the exciting coil 17 is inserted in an intermediate electrode circuit 15
  • the contact 18 is selectively connected between the terminals 14 and 14 of the reduction resistor 13 to provide an open or short-circuit therebetween.
  • relay 16 is adapted to normally short-circuit both terminals 14 and 14' of the reduction resistor 13 when a current does not flow through the circuit 15, namely, the contact 18 is a socalled break contact which remains closed when the relay 16 is not energized.
  • the life of the filament can be extended remarkably as compared with the prior art.
  • an ion source device for an ion micro-analyzer and the like comprising a filament for emitting electrons
  • a heating power source connected in circuit to said filament for supplying a filament current to said filament at a starting value necessary to initiate a gaseous discharge in the space adjacent said intermediate electrode
  • filament current control means responsive to a discharge current flowing from said first voltage source to said intermediate electrode for reducing and maintaining said filament current at a lesser value than said starting value, which lesser value is still sufficient to maintain said discharge.
  • said filament current control means includes switching means for selectively increasing the resistance of said filament circuit in response to detection of said discharge current.
  • said filament current control means includes a current reduction resistor connected in series between said filament and said heating power source, and switching means normally short-circuiting said current reduction resistor for removing said short-circuit in response to said discharge current, so as to reduce said filament current in the steady operating state of said device.
  • said switching means includes a movable switch contact normally connected across said current reduction resistor and an operating winding connected between said first voltage source and said intermediate electrode for actuating said movable switch contact when energized by current flow.

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  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Electron Tubes For Measurement (AREA)
  • Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
  • Electron Sources, Ion Sources (AREA)

Abstract

An ion source device of the Duoplasmatron type has a current reduction resistor in the filament circuit thereof for reducing the filament current during steady state operation thereof, and a relay adapted to normally short-circuit both terminals of the current reduction resistor, which relay is energized by a current flowing through an intermediate electrode circuit so as to open both of these terminals of the resistor thereby making it possible to reduce the steady state filament current.

Description

United States Patent Kondo et a1.
[54] ION SOURCE DEVICE HAVING CONTROL MEANS FOR REDUCING FILAMENT CURRENT BELOW ITS STARTING VALUE Inventors: Toshio Kondo/Kokubunji; Hifumi 'Iamura, Hachioji, both of Japan Assignee: Hitachi, Ltd., Tokyo, Japan Filed: 1811.11, 1971 Appl. No.: 105,321
' Foreign Application Priority Data Jan. 9, 1970 Japan "45/5124 US. Cl ..315/74, 315/107, 3l5/DlG. 5 Int. Cl ..H0lj 33/00 Field of Search .....315/107, 106, 74, DIG. 5;
[56] References Cited UNITED STATES PATENTS 2 ,5 1 9 1 gt 31:11:23.1: 11:. Y
[ 1 Oct. 17, 1972 3,413,517 11/1968 Barber et a1. ..3l5/l07 X 3,567,995 3/1971 Lauritzen et a1. ...3 15/106 UX Primary Examiner-Paul L. Gensler Attorney-Craig, Antonelli, Stewart & Hill [57] ABSTRACT 6 Claims, 2 Drawing Figures '5 up l2 '3 DC. HEATING i I m I I l4 l4 DC. ACCELER- I ATING VOLT- 1 AGE SOURCE l6 i L L WEI. 3 2 4 9 I7 18 ,7 Y \s 1 & ION ACCELER---- ATING H VOLI- g 5 IAGE SOURCE 1 PATE'NTEDocmmz g I 3,699,381
05:. HEATING L,
ANODE CURRENT (A) 'l 2 3 4 5 6 FILAMENT CURRENT (A) INVENTORS Tosmo KONDO AND HIFUMH rmu'm Gnu l9, qnlbnalligsicuxml I I AT TORNEYS ION SOURCE'DEVICEHAVING CONTROL MEANS FOR REDUCING FILAMENT CURRENT BELOW l s STARTING VALUE This inventionrelates to an ion source device for an ion microanalyzer and the like and, more particularly, to an ion source device of the Duoplasmatron type having means for reducing the filament current during steady state operation thereof.
BACKGROUND OF THE INVENTION filament current is less than that of the starting filament current. Therefore, it is apparent that in such conventional devices the steady state filamentv current has an unnecessarily large value and thus the life of the filament therein becomes very short.
SUMMARY OF TI-IE'INVENTION An object of this invention is to provide means for making it possible to reduce the steady filamentcurrent in an ion microanalyzer of the type described.
This invention is characterized in that a current reduction resistor is inserted in the filament heating circuit and switching means is arranged so as to short-circuit both terminals of the reduction resistor. With a view to function, when said discharge occurs, the switching means is energized by a current flowing through an intermediate electrode circuit which causes both terminals to open so that the filament current flows through the current reduction resistor and the steady state filament current for maintaining discharge is reduced.
This and other objects, advantages andfeatures of the present invention will become more apparent from the following detailed description with reference to the accompanying drawings, wherein:
FIG. I is a schematic circuit diagram indicating an I embodiment of this invention.
FIG. 2 shows the relationship between filament current and anode current in an ion source device.
DESCRIPTION OF A PREFERRED EMBODIMENT In FIG. I, a filament 2 is connected to a d. c. heating power source 1 which provides heater current thereto, and a d. c. accelerating voltage source 3 is connected between an intermediate electrode 4 and the filament 2 so as to accelerate electrons emitted from said filament.
A magnet 6 made Of ferrite is disposed between said intermediate electrode 4 and an anode 5 so as to insulate these elements and to concentrate the electrons in the space therebetween. A gas having a constant quantity is supplied to a space adjacent to said intermediate electrode 4 by proper means (not shown) and ionized as a result of discharge occurring due to impingement v with said electrons.
An ion accelerating high voltage source 7 is connected between said anode 5 and an extractor 8 so that the ions are extracted therefrom by said extractor 8 and further are introduced into an ion microanalyzer (not shown) so that the ions are directed to a speciment in a known manner. Moreover, aresistor 9 is inserted in said intermediate electrode circuit. Both secondary windings of the insulating transformers l0 and 11 are connected to the respective inputs of the power sources 1 and 3, and both primary windings thereof are connected to an a. 0. power source (not shown).
In the ion source device as above-described, there is a relationship between the filament current and the anode current as shown in FIG. 2. As is apparent from said'relationship, even if the minimum steady filament current I is less than the starting filament current I discharge caused to occur once can be maintained.
According to this invention, in order to attain a reduction in the steady filament current, a current reduction resistor 13 and a relay 16 having an exciting coil 17 and a contact 18- are disposed in the system, in addition to the above-described elements. The current reduction resistor 13 is inserted in the filament circuit 12, the exciting coil 17 is inserted in an intermediate electrode circuit 15 and the contact 18 is selectively connected between the terminals 14 and 14 of the reduction resistor 13 to provide an open or short-circuit therebetween. Further, relay 16 is adapted to normally short-circuit both terminals 14 and 14' of the reduction resistor 13 when a current does not flow through the circuit 15, namely, the contact 18 is a socalled break contact which remains closed when the relay 16 is not energized.
Now, when the filament current whose value is larger than that of said starting filament current is applied to said filament 2, a discharge begins. As a result of said discharge, the current flows through the circuit 15 and energizes the relay 16, so that the contact 18 opens and the filament current flows through the reduction resistor 13. Consequently, the value of the filament current becomes less than that of the starting filament current. The contact 19 is kept in the open state during further operation of the ion source device.
According to this invention, since it is possible to reduce the filament current during steady state operation of said ion source device, the life of the filament can be extended remarkably as compared with the prior art.
While we have shown and described one embodiment in accordance with the present invention, it is understood that the same is not limited thereto but is susceptible of numerous changes and modifications as known to a person skilled in the art, and we therefore do not wish to be limited to the details shown and described herein but intend to cover all such changes and modifications as are obvious to one of ordinary skill in the art.
We claim:
1. In an ion source device for an ion micro-analyzer and the like comprising a filament for emitting electrons,
an intermediate electrode for accelerating said electrons emitted from said filament,
a heating power source connected in circuit to said filament for supplying a filament current to said filament at a starting value necessary to initiate a gaseous discharge in the space adjacent said intermediate electrode,
a first voltage source connected between said filament and said intermediate electrode,
anode means for accelerating ions produced in the space adjacent said intermediate electrode,
a magnet disposed between said intermediate electrode and said anode for concentrating said ions, and
an extractor of said ions and a second voltage source connected between said extractor and said anode,
the improvement which comprises filament current control means responsive to a discharge current flowing from said first voltage source to said intermediate electrode for reducing and maintaining said filament current at a lesser value than said starting value, which lesser value is still sufficient to maintain said discharge.
2. The combination defined in claim 1, wherein said filament current control means includes switching means for selectively increasing the resistance of said filament circuit in response to detection of said discharge current.
3. The combination defined in claim 1, wherein said magnet is made of an electrical insulating material and is disposed in contact with said intermediate electrode and said anode.
4. The combination defined in claim 1, wherein said filament current control means includes a current reduction resistor connected in series between said filament and said heating power source, and switching means normally short-circuiting said current reduction resistor for removing said short-circuit in response to said discharge current, so as to reduce said filament current in the steady operating state of said device.-
5. The combination defined in claim 4, wherein said switching means includes a movable switch contact normally connected across said current reduction resistor and an operating winding connected between said first voltage source and said intermediate electrode for actuating said movable switch contact when energized by current flow.
6. The combination defined in claim 5, wherein said magnet is made of an electrical insulating material and is disposed in contact with said intermediate electrode and said anode.

Claims (6)

1. In an ion source device for an ion micro-analyzer and the like comprising a filament for emitting electrons, an intermediate electrode for accelerating said electrons emitted from said filament, a heating power source connected in circuit to said filament for supplying a filament current to said filament at a starting value necessary to initiate a gaseous discharge in the space adjacent said intermediate electrode, a first voltage source connected between said filament and said intermediate electrode, anode means for accelerating ions produced in the space adjacent said intermediate electrode, a magnet disposed between said intermediate electrode and said anode for concentrating said ions, and an extractor of said ions and a second voltage source connected between said extractor and said anode, the improvement which comprises filament current control means responsive to a discharge current flowing from said first voltage sOurce to said intermediate electrode for reducing and maintaining said filament current at a lesser value than said starting value, which lesser value is still sufficient to maintain said discharge.
2. The combination defined in claim 1, wherein said filament current control means includes switching means for selectively increasing the resistance of said filament circuit in response to detection of said discharge current.
3. The combination defined in claim 1, wherein said magnet is made of an electrical insulating material and is disposed in contact with said intermediate electrode and said anode.
4. The combination defined in claim 1, wherein said filament current control means includes a current reduction resistor connected in series between said filament and said heating power source, and switching means normally short-circuiting said current reduction resistor for removing said short-circuit in response to said discharge current, so as to reduce said filament current in the steady operating state of said device.
5. The combination defined in claim 4, wherein said switching means includes a movable switch contact normally connected across said current reduction resistor and an operating winding connected between said first voltage source and said intermediate electrode for actuating said movable switch contact when energized by current flow.
6. The combination defined in claim 5, wherein said magnet is made of an electrical insulating material and is disposed in contact with said intermediate electrode and said anode.
US105321A 1970-01-09 1971-01-11 Ion source device having control means for reducing filament current below its starting value Expired - Lifetime US3699381A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4317983A (en) * 1978-10-10 1982-03-02 Steigerwald Strahltechnik Gmbh Setting the electron gun cathode heating current of an electron beam machine
EP0464969A2 (en) * 1990-06-02 1992-01-08 Deutsches Elektronen-Synchrotron DESY Tension feeding circuit for a helium leak detector

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2519173A (en) * 1946-06-12 1950-08-15 Rca Corp Regulating device
US3413517A (en) * 1967-01-13 1968-11-26 Ibm Filament current control by a superposed dithering voltage
US3567995A (en) * 1968-08-12 1971-03-02 Automation Ind Inc Current stabilizer circuit for thermionic electron emission device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2519173A (en) * 1946-06-12 1950-08-15 Rca Corp Regulating device
US3413517A (en) * 1967-01-13 1968-11-26 Ibm Filament current control by a superposed dithering voltage
US3567995A (en) * 1968-08-12 1971-03-02 Automation Ind Inc Current stabilizer circuit for thermionic electron emission device

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4317983A (en) * 1978-10-10 1982-03-02 Steigerwald Strahltechnik Gmbh Setting the electron gun cathode heating current of an electron beam machine
EP0464969A2 (en) * 1990-06-02 1992-01-08 Deutsches Elektronen-Synchrotron DESY Tension feeding circuit for a helium leak detector
EP0464969A3 (en) * 1990-06-02 1992-09-02 Deutsches Elektronen-Synchrotron Desy Tension feeding circuit for a helium leak detector

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DE2100506B2 (en) 1973-07-19
DE2100506C3 (en) 1974-02-07
DE2100506A1 (en) 1971-07-15

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