WO2019244874A1 - Cold cathode electron source and x-ray generator equipped with same - Google Patents

Cold cathode electron source and x-ray generator equipped with same Download PDF

Info

Publication number
WO2019244874A1
WO2019244874A1 PCT/JP2019/024045 JP2019024045W WO2019244874A1 WO 2019244874 A1 WO2019244874 A1 WO 2019244874A1 JP 2019024045 W JP2019024045 W JP 2019024045W WO 2019244874 A1 WO2019244874 A1 WO 2019244874A1
Authority
WO
WIPO (PCT)
Prior art keywords
cold cathode
cathode electron
ray
source
electron
Prior art date
Application number
PCT/JP2019/024045
Other languages
French (fr)
Japanese (ja)
Inventor
均 桝谷
秀憲 監物
Original Assignee
ナノックス イメージング ピーエルシー
株式会社ナノックスジャパン
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 ナノックス イメージング ピーエルシー, 株式会社ナノックスジャパン filed Critical ナノックス イメージング ピーエルシー
Publication of WO2019244874A1 publication Critical patent/WO2019244874A1/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J35/00—X-ray tubes
    • H01J35/02—Details
    • H01J35/04—Electrodes ; Mutual position thereof; Constructional adaptations therefor
    • H01J35/06—Cathodes

Definitions

  • the present invention relates to a cold cathode electron source and an X-ray generator including the same, and more particularly, to a modularized cold cathode electron source and an X-ray generator including the same.
  • X-rays used for fluoroscopy for medical or other purposes are usually created by the energy that electrons generated from a cathode are accelerated in a vacuum vessel toward an anode and lost by colliding with the anode.
  • Such an X-ray generator is configured such that one anode having a cathode electron collision point and generating X-rays and a cathode having one or two electron sources are joined to a glass container, a metal container or a glass container and a metal container. It is generally called an X-ray tube or X-ray source (hereinafter, referred to as “X-ray source”).
  • a conventional X-ray source is manufactured through an exhaust quenching process for making the inside of a container a high vacuum.
  • both the anode and the cathode are often permanently sealed in the container by welding or brazing, except for some “open” X-ray sources. In this case, the anode or the cathode cannot be easily replaced.
  • thermoelectrons emitted from filaments or other heating elements as cathode electrons. For this reason, it is difficult to quickly switch the electron sources during use, and the number of electron sources in one container is limited to about two.
  • An X-ray source generally used for fluoroscopy for medical and other uses includes an anode having one X-ray generating point, a cathode having one or two electron sources, a glass tube (or a ceramic tube, and a metal tube for them).
  • the housing is sometimes sealed) or enclosed in a metal housing (sometimes ceramic parts are joined).
  • FIG. 1 is a schematic diagram of a "sealed" X-ray tube using a glass tube 1a for a vacuum vessel.
  • An anode 1b and a cathode 1c are sealed in the glass tube 1a.
  • One or two thermoelectron sources 1e such as filaments are mounted on the cathode 1c.
  • a part of the anode 1b and a conducting wire 1g connected to the thermionic source 1e and the focusing electrode 1f constituting the cathode 1c are drawn out through the glass tube 1a.
  • Cathode portion 1a 2 of the glass tube 1a is also made of metal, in this case, among the cathode side portions 1a 2 made of metal, parts lead 1g penetrates is replaced with an insulating material.
  • Anode portion 1a 1 of the glass tube 1a can be a ceramic.
  • the electrons emitted from the thermionic source 1e are accelerated in a vacuum and collide with the target surface of the anode 1b, from which X-rays are emitted in the side direction of the glass tube 1a.
  • FIG. 2 is a schematic diagram of a "sealed" X-ray tube using the metal housing 2a as a vacuum container.
  • An anode 2b and a cathode 2c are sealed in the metal housing 2a.
  • an insulating material 2b 1 is provided between the metal casing 2a and the anode 2b.
  • a metal housing 2a, between the connected wires 2g cathode 2c, the insulating material 2c 1 is provided.
  • the principle of generating X-rays is the same as that of the X-ray tube shown in FIG. 1, but the X-ray tube shown in FIG. Is provided.
  • a part of the transmission type X-ray source for obtaining high-resolution fluoroscopic images with micro focus and small current can open the metal housing and replace the cathode etc. while maintaining a constant vacuum with a vacuum pump.
  • a “type” other reflective X-ray sources that require a larger current for industrial or medical use are mostly “sealed” as shown in FIG. 1 or FIG. No consideration is given to replacing the cathode or the like.
  • FIG. 3 is a schematic diagram of an “open” X-ray tube.
  • Vacuum vessel the anode side metal casing 3a 1 and is divided into the metal casing 3a 2 on the cathode side, it can be decomposed as needed.
  • the metal casing 3a 1, the anode 3b is fixed consisting of a metal film via an insulator 3b 1.
  • Cathode 3c connected to conductor 3g is fixed to the metal housing 3a 2.
  • a metal housing 3a 2, between the conductors 3g connected to the cathode. 3c, insulating material 3c 1 is provided.
  • Thermionic source 3e included in the cathode 3c are usually single filament, when worn can be replaced by opening the metal housing 3a 2.
  • the metal casings 3a 1 and 3a 2 are sealed and evacuated constantly by the vacuum pump 3i.
  • the electrons emitted from the cathode 3c are accelerated in a vacuum, collide with the anode 3b, and emit X-rays in a direction opposite to the direction of the cathode 3c.
  • X-rays aperture 3h is provided on a line connecting a cathode 3c and anode 3b of the metal housing 3a 1.
  • the “sealed” X-ray source is an effective method when a vacuum pump is not required at the time of use and sufficient life is ensured for the anode target surface and the cathode filament.
  • a stable manufacturing method is not established as in the thermionic electron source, and there is a high possibility that the performance varies. For this reason, when a cold cathode is used as the electron source of the X-ray source, there is a problem that the cathode cannot be easily replaced with the conventional “sealed type” structure.
  • the cold cathode electron source itself, as shown in FIG. 4, electrons are drawn into a vacuum from a fine conical emitter made of a metal such as molybdenum by an electric field created by a peripheral gate electrode.
  • the current distribution in the electron beam cross section of the thermionic source is made uniform so that the largest possible current can be supplied without melting the anode target.
  • the shape of the electron source and the peripheral mechanism have been devised. This control of the current distribution in the cross section of the electron beam can be performed more directly by adjusting the shape and position of many emitters and carbon nanotubes that constitute one electron beam in the cold cathode electron source. become.
  • FIG. 4 is a schematic view showing a "Spindt-type" X-ray source which is one of the cold cathode electron sources.
  • the Spindt-type cold cathode electron source a large number of sets of a fine cone 4e made of a metal such as molybdenum and a gate 4g as a lead electrode surrounding the cone 4e on the circumference thereof are arranged in a large number.
  • a voltage is applied to the gate 4g, electrons are emitted from the tip of the cone 4e and collide with the anode 4b to generate X-rays.
  • One X-ray emission range is usually designed to collide with electrons emitted from more than 100 cones 3e.
  • FIG. 5 is a schematic diagram showing a “CNT type” X-ray source which is another cold cathode electron source.
  • the CNT type X-ray source it is possible to fix a large number of carbon nanotubes 5e having fine tips with a conductive binder 5f, and arrange a mesh electrode 5g as an extraction electrode between the anode 5b and the carbon nanotube 5e.
  • a voltage is applied to the mesh electrode 5g, electrons are emitted from the tip of the carbon nanotube 5e, and the electrons passing through the mesh electrode 5g collide with the anode 5b to generate X-rays.
  • the tip of the carbon nanotube 5e corresponding to one X-ray emission range is usually 100 or more.
  • a first object of the present invention is to make it possible to replace a cold cathode electron source by making the X-ray source into a modular structure and to facilitate manufacture and maintenance of the X-ray source using the cold cathode electron source. .
  • a second object of the present invention is to make an opening of a vacuum vessel provided for inserting a cold cathode electron source smaller in an X-ray source having three or more cold cathode electron sources.
  • a third object of the present invention is to reduce the number of wirings drawn out of a vacuum vessel to the outside in an X-ray source having three or more cold cathode electron sources.
  • a fourth object of the present invention is to make the electron collision density in the X-ray generation range (X-ray focal point) of the anode more uniform in an X-ray source having three or more cold cathode electron sources.
  • An X-ray generator includes a vacuum vessel having an opening, an anode at least partially located inside the vacuum vessel, and a vacuum vessel detachable from the vacuum vessel and closing the opening. And a cathode including a cold cathode electron source fixed to the flange and located inside the vacuum vessel.
  • a plurality of cold cathode electron sources are arranged on a gantry extending in a predetermined direction, a connection point of the gantry with respect to the flange is provided at a position offset from a center portion of the gantry in a predetermined direction, and a diameter of the opening is It may be smaller than the length of the gantry in a predetermined direction. According to this, the opening of the vacuum container provided for inserting the cold cathode electron source can be made smaller.
  • the cold cathode electron source has a plurality of fine tips and a plurality of extraction electrodes respectively corresponding to the plurality of fine tips, and a common wiring is formed on a part of the plurality of fine tips or a part of the plurality of extraction electrodes. It may be assigned. According to this, it is possible to reduce the number of wires drawn out from the vacuum container.
  • a plurality of cold cathode electron sources are provided, each of the plurality of cold cathode electron sources includes an electron beam focusing mechanism having a plurality of electrodes, and a plurality of electrodes belonging to different cold cathode electron sources are assigned a common wiring. No problem. According to this, it is possible to reduce the number of wires drawn out from the vacuum container.
  • a cold cathode electron source is a cold cathode electron source having a plurality of fine tips, wherein the plurality of fine tips have a first group disposed in a central region and a peripheral region surrounding the central region. And the amount of current per unit area of the electron beam emitted from the second group is larger than the amount of current per unit area of the electron beam emitted from the first group. .
  • the X-ray generator According to the X-ray generator according to one aspect of the present invention, manufacture and maintenance of the X-ray source are facilitated.
  • the electron collision density in the X-ray generation range (X-ray focus) of the anode becomes more uniform.
  • FIG. 1 is a schematic diagram of a "sealed” X-ray tube using a glass tube 1a for a vacuum vessel.
  • FIG. 2 is a schematic diagram of a "sealed” X-ray tube using the metal housing 2a as a vacuum container.
  • FIG. 3 is a schematic diagram of an “open” X-ray tube.
  • FIG. 4 is a schematic diagram showing a "Spindt-type” X-ray source which is one of the cold cathode electron sources.
  • FIG. 5 is a schematic diagram showing a “CNT type” X-ray source which is another cold cathode electron source.
  • FIG. 6 is a schematic diagram showing the structure of the X-ray source according to the first embodiment of the present invention.
  • FIG. 1 is a schematic diagram of a "sealed” X-ray tube using a glass tube 1a for a vacuum vessel.
  • FIG. 2 is a schematic diagram of a "sealed” X-
  • FIG. 7 is a schematic diagram showing the structure around the cathode of the X-ray source according to the second embodiment of the present invention.
  • FIG. 8 is a schematic diagram showing a method of connecting the cathodes of three or more cold cathode electron sources and the lead wires of the extraction electrodes in the “Spindt type” cold cathode electron source.
  • FIG. 9 is a schematic diagram for explaining the operation of the X-ray source according to the third embodiment of the present invention.
  • FIG. 10 is a schematic view for explaining a current distribution in a cross section of an electron beam when an electron emitted from a plurality of fine tips is used as one electron beam in an X-ray source using a cold cathode electron source.
  • FIG. 11 is a schematic diagram for explaining a first method for making the electron collision density more uniform.
  • FIG. 12 is a schematic diagram for explaining a second method for making the electron collision density more uniform.
  • FIG. 6 is a schematic diagram showing the structure of the X-ray source according to the first embodiment of the present invention.
  • the X-ray source according to the first embodiment is a “sealed” X-ray source and comprises a vacuum vessel 6a.
  • Vacuum container 6a is made cylindrical casing 6a 1 and the metal casing 6a 2 made of glass or ceramic, in its interior one or two cold-cathode electron source 6e and the focus electrode 6f is enclosed.
  • the cold cathode electron source 6e and the focusing electrode 6f are connected to the outside of the vacuum vessel 6a via a conductive wire 6g.
  • An anode 6a 3 is fixed to the cylindrical casing 6a 1.
  • the metal housing 6a 2 is provided with a vacuum pump connection 6b for evacuating during manufacture, and the opening 6d of the ring-shaped metal flange 6c are connected, the aperture 6h for irradiating X-rays to the outside.
  • the vacuum pump connection portion 6b is made of glass or ceramic, is connected to a vacuum pump in a manufacturing stage, and is evacuated until the inside of the vacuum container 6a becomes substantially vacuum, and then sealed.
  • Metal flange 6c is connected to the metal casing 6a 2 via a sealing ring 6c 1, it is fixed to the metal housing 6a 2 by using a bolt 6c 2.
  • the region surrounded by the ring-shaped metal flange 6c is provided an insulator 6c 3.
  • the X-ray source according to the first embodiment is a “sealed” X-ray source, in which the cathode part can be replaced at least during manufacture.
  • the metal flange 6c is removed and a new one is removed.
  • members other than the cathode can be used.
  • the metal flange 6c is opened and replaced with a metal flange 6c on which a new cathode is mounted.
  • the vacuum pump connection portion 6b may be opened, the inside of the vacuum container 6a may be evacuated using a vacuum pump until the inside of the vacuum container 6a becomes substantially vacuum, and then sealed again.
  • the X-ray source according to the present embodiment is configured such that the cathode including the cold cathode electron source 6e and the focusing electrode 6f can be exchanged. It is not necessary to dispose of the entire source, only the cathode part can be replaced. Also, the flange need not be made of metal.
  • FIG. 7A is a schematic diagram showing the structure around the cathode of the X-ray source according to the second embodiment of the present invention.
  • the X-ray source according to the second embodiment is a "sealed" X-ray source having a cathode including three or more cold cathode electron sources E1 to En.
  • Vacuum vessel 7a 2 is made of metal, using the same method as shown in FIG. 6, the metal flange 7c and the vacuum chamber 7a 2 which are cathode and integrally formed is fixed.
  • n (n is 3 or more) cold cathode electron sources E1 to En are linearly arranged on one mount 7j.
  • the length of the gantry 7j is greater than the diameter of the opening 7d provided in the metal housing 7a 2.
  • strut 7c 4 connected to the metal flange 7c is connected to the connection point 7k near the end of the gantry 7j I have.
  • a plurality arranging it as shown in FIG. 7 (b) the structure shown in FIG. 7 (a) may be more cold-cathode electron source arranged inside the metal enclosure 7a 2.
  • three metal flanges 7c 1 to 7c 3 and three mounts 7j 1 to 7j 3 are used, and the cold cathodes provided on these mounts 7j 1 to 7j 3 are used.
  • the pitch of the electron source is kept constant.
  • FIGS. 8 (a) to 8 (c) are schematic views showing a connection method between the cathodes of three or more cold cathode electron sources and the lead wires of the extraction electrodes in the "Spindt type" cold cathode electron source.
  • the cathodes of the cold cathode electron sources E1 to En are all connected to a common wiring, while the extraction electrodes are connected to individual wirings for the cold cathode electron sources E1 to En. ing.
  • one or more arbitrary cold cathode electron sources E1 to En can be driven by applying a voltage to the extraction electrode.
  • the number of conducting wires passing through the metal flange 7c is n + 1.
  • the X-ray source according to the second embodiment is a "sealed" X-ray source having a cathode containing three or more cold cathode electron sources, wherein at least during manufacture the cathode part can be replaced. ing.
  • the basic components and the method of use are the same as those of the X-ray source according to the first embodiment.
  • the X-ray source according to the second embodiment includes three or more cold cathode electron sources, so that the overall size of the cold cathode electron source increases. .
  • it is enlarging the diameter of the opening 7d for inserting the cold cathode electron source in the vacuum chamber 7a 2 not preferable to hold the vacuum.
  • the X-ray source according to the second embodiment has three or more cold cathode electron sources arranged in a straight line on the gantry 7j, and has one end of the gantry 7j, that is, the center of the gantry 7j.
  • the connection point 7k By providing the connection point 7k at a position offset from, the opening 7d having a smaller diameter can be used.
  • the number of the cold cathode electron sources is n
  • the cathode and the extraction electrodes are individually wired, 2 ⁇ n conductors are required.
  • the wiring connected to the cathode is made common, and the wiring connected to the extraction electrode is made individual, or as shown in FIG. If the wirings connected to the extraction electrode are made common and the wirings connected to the extraction electrode are made common, the number of wirings can be reduced to n + 1.
  • FIG. 8 (c) may be disposed a control circuit 8m for controlling a voltage applied to the cathode or the extraction electrode individually in the vacuum chamber 7a 2.
  • FIG. 9 is a schematic diagram for explaining the operation of the X-ray source according to the third embodiment of the present invention.
  • the X-ray source according to the third embodiment includes three or more cold cathode electron sources, and the shape and direction of the electron beam can be controlled by the voltage applied to the electrodes p, q, and r.
  • a cold cathode electron source As a cold cathode electron source, a "Spindt type" is assumed.
  • the electrodes p1 to pn, the electrodes q1 to qn, and the electrodes r1 to rn are connected to a common wiring. Therefore, the same convergence condition is provided for electron sources other than the active electron source. Of course, inactive electron sources have no effect.
  • M ⁇ n wirings are required. In the example shown in FIG. Wiring is enough.
  • the n cold cathode electron sources E1 to En are divided into several groups (two groups in this example), and the electrodes p, q, and r are shared by common wiring for each group. Connected.
  • the electrodes p1 and pn are connected to a common line
  • the electrodes q1 and qn are connected to a common line
  • the electrodes r1 and rn are connected to a common line. It is connected to the.
  • the electrodes p2 and p3 are connected to a common wiring
  • the electrodes q2 and q3 are connected to a common wiring
  • the electrodes r2 and r3 are connected to a common wiring. Connected to wiring.
  • the example shown in FIG. 9B is useful when it is necessary to operate a plurality of electron sources simultaneously.
  • relay circuits 9L1 to 9Ln are connected to the convergence mechanisms of the cold cathode electron sources E1 to En, respectively, and a control circuit 9m for controlling these is provided. Can be driven. If the control circuit 9m is arranged near the cathode so as to be located inside the vacuum vessel, it is possible to greatly reduce the number of wires penetrating the vacuum vessel.
  • FIG. 10 is a schematic view for explaining a current distribution in a cross section of an electron beam when an electron emitted from a plurality of fine tips is used as one electron beam in an X-ray source using a cold cathode electron source.
  • FIG. 10 One of electrons exiting the micro-tip 10e 0 collides with a certain range t0 on the anode target 10b, in the collision location, collided heat and X-rays corresponding to the number of electrons are emitted.
  • the density distribution of the colliding electrons is s0.
  • Position ranges t0 to electron collision is determined by the position of the fine tip 10e 0, when the sum of the electron (electron beam) from all the fine tip 10e 0, the density distribution of electrons in the region T becomes S.
  • This density distribution S corresponds to the heat generation distribution on the anode target 10b and the X-ray generation distribution generated therefrom.
  • the X-ray dose obtained here is defined as Xs in the range of Tx.
  • the electron collision density is as uniform as possible in the X-ray generation range (X-ray focal point).
  • FIG. 11 As one of the measures to make the electron collision density more uniform in the X-ray generation range (X-ray focal point), there is a method shown in FIG.
  • FIG. 11 there are many fine tips of the cold cathode electron source, and the arrangement is adjusted. That is, the density of the fine tip of the cold cathode electron source is coarsely adjusted at the central portion and the peripheral portion is reduced so that the electron density becomes coarse at the center of the electron collision range on the anode target 11b and the electron density becomes dense at the peripheral portion. To be densely arranged.
  • the example shown in FIG. 11A controls the current distribution S in the cross section of the electron beam in the X-ray source according to the fourth embodiment.
  • the fine tip 11e 0 irradiates the electron beam to the central part of the range T
  • the fine tips 11e 3 and 11e 4 irradiates the peripheral part of the range T to the electron beam.
  • the fine tips 11e 1 and 11e 2 irradiate an electron beam between a central portion and a peripheral portion of the range T.
  • the distance between the fine tips 11e 0 to 11e 4 is narrow between the fine tips 11e 1 to 11e 3 and between the fine tips 11e 2 to 11e 4, and the distance between the fine tips 11e 0 to 11e 1 and 11e 0 to 11e. Wide between the two .
  • the difference between the center part and the peripheral part becomes smaller. .
  • the X-ray dose Xs ′ obtained in the range Tx is larger than the X-ray dose Xs in FIG.
  • FIG. 11B shows a method for realizing a similar configuration with carbon nanotubes.
  • FIG. 12 Another method for making the electron collision density more uniform in the X-ray generation range (X-ray focus) is the method shown in FIG.
  • the example shown in FIG. 12 is for adjusting the amount of electron emission for each fine tip, a method of applying a different extraction voltage for each location of the fine tip, and a circuit for adjusting the extraction voltage for each location of the fine tip. And a method in which the fine tip is manufactured so as to have different electron emission efficiencies at different locations.
  • FIGS. 12A to 12C are schematic diagrams showing a method of controlling the current distribution S while keeping the arrangement pitch of the fine tips constant on the premise of the “Spindt” cold cathode electron source.
  • Figure in 12 (a) ⁇ (c) a plurality of micro-tip 12e 1 is arranged in the central area, it is arranged a plurality of fine tip 12e 3 to the peripheral region, a plurality of micro-tip 12e 2 is disposed in the middle region Have been.
  • a low voltage is applied to the fine tip 12e 1 disposed in the central region where electrons collide with the central part of the range T, the peripheral region that impinges on the periphery of the electronic range T to apply a high voltage to a fine tip 12e 3 that placed on.
  • the central region and the intermediate region are connected via a resistor R1
  • the peripheral region and the intermediate region are connected via a resistor R2
  • a predetermined voltage is applied to the peripheral region.
  • the voltage drop due to the resistance R1, R2 is a lower voltage is applied to the fine tip 12e 1
  • a high voltage is applied to the fine tip 12e 3.
  • a low cathode resistance in fine tip 12e 1 can also be achieved by increasing the fine tip 12e 3.
  • the same extraction voltage is applied to the fine tips 12e 1 to 12e 3 , but the electron emission efficiency is low in the fine tip 12e 1 located in the central region, and the fine tips located in the peripheral region are low. so that the electron emission efficiency becomes higher in 12e 3, designing the shape of the fine tip 12e 1 ⁇ 12e 3.
  • the electron emission efficiency can be changed by changing the distance from the fine tips 12e 1 to 12e 3 to the gate electrode.

Abstract

The purpose of the present invention is to provide a modular structure for an X-ray source which allows for the replacement of a cold cathode electron source, thereby facilitating the production and maintenance of an X-ray source that uses a cold cathode electron source. An X-ray generator according to an aspect of the present invention comprises: a vacuum container having an opening; an anode at least a portion of which is located inside the vacuum container; a flange which is detachably attached to the vacuum container and secured to the vacuum container to close the opening thereof; and a cathode secured to the flange and including a cold cathode electron source located inside the vacuum container. This makes it possible to easily and replace just a cathode section.

Description

冷陰極電子源及びこれを備えるＸ線発生装置Cold cathode electron source and X-ray generator including the same
　本発明は冷陰極電子源及びこれを備えるＸ線発生装置に関し、特に、モジュール化された冷陰極電子源及びこれを備えるＸ線発生装置に関する。 The present invention relates to a cold cathode electron source and an X-ray generator including the same, and more particularly, to a modularized cold cathode electron source and an X-ray generator including the same.
　医療用又はその他用途の透視撮影に用いられるＸ線は、陰極から発生する電子が真空容器内で陽極に向かって加速され、陽極と衝突することで失うエネルギーによって作り出されることが通例である。このようなＸ線発生装置は、陰極電子衝突点を持ちＸ線を発生させる一つの陽極と、一つ又は二つの電子源を持つ陰極を、ガラス容器、金属容器あるいはガラス容器と金属容器を接合した容器に封入した構成を有しており、一般に、Ｘ線管またはＸ線源と呼ばれる（以下、「Ｘ線源」で呼称統一する）。 X-rays used for fluoroscopy for medical or other purposes are usually created by the energy that electrons generated from a cathode are accelerated in a vacuum vessel toward an anode and lost by colliding with the anode. Such an X-ray generator is configured such that one anode having a cathode electron collision point and generating X-rays and a cathode having one or two electron sources are joined to a glass container, a metal container or a glass container and a metal container. It is generally called an X-ray tube or X-ray source (hereinafter, referred to as “X-ray source”).
　従来のＸ線源は、容器内を高真空にするための排気焼き入れ工程を経て作製される。また、容器内を高真空に維持する観点から、陽極、陰極ともに、溶接やろう付けなどの方法で恒久的に容器に封入することが多く、一部の「開放式」Ｘ線源を除いて、陽極または陰極を容易に交換することができない構造となっていた。 A conventional X-ray source is manufactured through an exhaust quenching process for making the inside of a container a high vacuum. In addition, from the viewpoint of maintaining a high vacuum inside the container, both the anode and the cathode are often permanently sealed in the container by welding or brazing, except for some “open” X-ray sources. In this case, the anode or the cathode cannot be easily replaced.
　また、従来のＸ線源は、陰極電子として、フィラメントその他の発熱体から出る熱電子を用いてきた。このため、使用中に電子源の切り替えを素早く行うことが難しく、一容器内の電子源は二個程度に限られていた。 従 来 In addition, conventional X-ray sources have used thermoelectrons emitted from filaments or other heating elements as cathode electrons. For this reason, it is difficult to quickly switch the electron sources during use, and the number of electron sources in one container is limited to about two.
　医療用その他用途の透視撮影に一般に用いられるＸ線源は、一のＸ線発生箇所を持つ陽極と、一つ又は二つの電子源を持つ陰極を、ガラス管（もしくはセラミック管、またそれらに金属筐体が接合される場合もある）、または金属筐体（セラミック部品が接合される場合もある）の中に封入する構造をとっている。 An X-ray source generally used for fluoroscopy for medical and other uses includes an anode having one X-ray generating point, a cathode having one or two electron sources, a glass tube (or a ceramic tube, and a metal tube for them). The housing is sometimes sealed) or enclosed in a metal housing (sometimes ceramic parts are joined).
　図１は、ガラス管１ａを真空容器に用いる「密閉型」Ｘ線管の模式図である。ガラス管１ａの中には、陽極１ｂと陰極１ｃが封入される。陰極１ｃには、フィラメントなどの熱電子源１ｅが一個ないし二個装着される。陽極１ｂの一部、並びに、陰極１ｃを構成する熱電子源１ｅや収束電極１ｆに接続される導線１ｇは、ガラス管１ａを貫通して外部に引き出される。ガラス管１ａの陰極側部分１ａ２は金属製である場合もあり、この場合は、金属からなる陰極側部分１ａ２のうち、導線１ｇが貫通する部分は絶縁素材で置き換えられる。ガラス管１ａの陽極側部分１ａ１はセラミック製である場合もある。熱電子源１ｅから出た電子は真空中で加速され、陽極１ｂのターゲット面に衝突し、ここからＸ線がガラス管１ａの側面方向に放射される。 FIG. 1 is a schematic diagram of a "sealed" X-ray tube using a glass tube 1a for a vacuum vessel. An anode 1b and a cathode 1c are sealed in the glass tube 1a. One or two thermoelectron sources 1e such as filaments are mounted on the cathode 1c. A part of the anode 1b and a conducting wire 1g connected to the thermionic source 1e and the focusing electrode 1f constituting the cathode 1c are drawn out through the glass tube 1a. Cathode portion 1a 2 of the glass tube 1a is also made of metal, in this case, among the cathode side portions 1a 2 made of metal, parts lead 1g penetrates is replaced with an insulating material. Anode portion 1a 1 of the glass tube 1a can be a ceramic. The electrons emitted from the thermionic source 1e are accelerated in a vacuum and collide with the target surface of the anode 1b, from which X-rays are emitted in the side direction of the glass tube 1a.
　図２は、金属筐体２ａを真空容器に用いる「密閉型」Ｘ線管の模式図である。金属筐体２ａには、陽極２ｂ及び陰極２ｃが封入される。金属筐体２ａと陽極２ｂの間には、絶縁素材２ｂ１が設けられる。金属筐体２ａと、陰極２ｃに接続された導線２ｇの間には、絶縁素材２ｃ１が設けられる。Ｘ線の発生原理は図１に示すＸ線管と同様であるが、図２に示すＸ線管は、金属筐体２ａを用いているため、Ｘ線を通しやすい開口２ｈが金属筐体２ａに設けられる。 FIG. 2 is a schematic diagram of a "sealed" X-ray tube using the metal housing 2a as a vacuum container. An anode 2b and a cathode 2c are sealed in the metal housing 2a. Between the metal casing 2a and the anode 2b, an insulating material 2b 1 is provided. A metal housing 2a, between the connected wires 2g cathode 2c, the insulating material 2c 1 is provided. The principle of generating X-rays is the same as that of the X-ray tube shown in FIG. 1, but the X-ray tube shown in FIG. Is provided.
　微小焦点・小電流で高解像度の透視画像を得るための透過型Ｘ線源の一部には、真空ポンプで常時真空を確保しつつ、金属筐体を開放して陰極等を交換できる「開放型」のものも存在するが、その他工業用や医療用で、より大きな電流を要する反射型Ｘ線源は、ほとんどが図１又は図２に示すような「密閉型」であり、製造・使用中に、陰極等を交換することは考慮されていない。 A part of the transmission type X-ray source for obtaining high-resolution fluoroscopic images with micro focus and small current can open the metal housing and replace the cathode etc. while maintaining a constant vacuum with a vacuum pump. Although there is a “type”, other reflective X-ray sources that require a larger current for industrial or medical use are mostly “sealed” as shown in FIG. 1 or FIG. No consideration is given to replacing the cathode or the like.
　図３は、「開放型」Ｘ線管の模式図である。真空容器は、陽極側の金属筐体３ａ１と陰極側の金属筐体３ａ２に分かれており、必要に応じて分解することができる。金属筐体３ａ１には、絶縁体３ｂ１を介して金属膜からなる陽極３ｂが固定される。金属筐体３ａ２には導線３ｇに接続された陰極３ｃが固定される。金属筐体３ａ２と、陰極３ｃに接続された導線３ｇの間には、絶縁素材 ３ｃ１が設けられる。陰極３ｃに含まれる熱電子源３ｅは通常一本のフィラメントであり、消耗した場合は金属筐体３ａ２を開放して交換することができる。熱電子源３ｅを交換した後は、金属筐体３ａ１，３ａ２を密閉し、真空ポンプ３ｉによって常時排気する。陰極３ｃから出た電子は真空中で加速され、陽極３ｂに衝突し、陰極３ｃとは反対方向にＸ線が放射される。したがって、Ｘ線開口３ｈは、金属筐体３ａ１のうち陰極３ｃと陽極３ｂを結ぶ線上に設けられる。 FIG. 3 is a schematic diagram of an “open” X-ray tube. Vacuum vessel, the anode side metal casing 3a 1 and is divided into the metal casing 3a 2 on the cathode side, it can be decomposed as needed. The metal casing 3a 1, the anode 3b is fixed consisting of a metal film via an insulator 3b 1. Cathode 3c connected to conductor 3g is fixed to the metal housing 3a 2. A metal housing 3a 2, between the conductors 3g connected to the cathode. 3c, insulating material 3c 1 is provided. Thermionic source 3e included in the cathode 3c are usually single filament, when worn can be replaced by opening the metal housing 3a 2. After the replacement of the thermionic source 3e, the metal casings 3a 1 and 3a 2 are sealed and evacuated constantly by the vacuum pump 3i. The electrons emitted from the cathode 3c are accelerated in a vacuum, collide with the anode 3b, and emit X-rays in a direction opposite to the direction of the cathode 3c. Thus, X-rays aperture 3h is provided on a line connecting a cathode 3c and anode 3b of the metal housing 3a 1.
　「密閉型」Ｘ線源は、使用時に真空ポンプを必要とせず、陽極のターゲット面や陰極のフィラメントに十分な寿命が確保されるときは、有効な方式である。しかしながら、Ｘ線源に用いられる冷陰極電子源は、熱電子源のように安定した製造方法が確立されておらず、性能にばらつきが生じる可能性が高い。このため、冷陰極をＸ線源の電子源に用いる場合、従来の「密閉型」構造では容易に陰極を交換できないことが問題となる。 The “sealed” X-ray source is an effective method when a vacuum pump is not required at the time of use and sufficient life is ensured for the anode target surface and the cathode filament. However, as for the cold cathode electron source used for the X-ray source, a stable manufacturing method is not established as in the thermionic electron source, and there is a high possibility that the performance varies. For this reason, when a cold cathode is used as the electron source of the X-ray source, there is a problem that the cathode cannot be easily replaced with the conventional “sealed type” structure.
　また「開放型」「密閉型」いずれの場合でも、従来のＸ線源の陰極に採用されてきたフィラメントなどの熱電子源は、複数設けた場合であっても、使用する熱電子源の切り替えを高速に行うことが不可能であるため、一つの電子源のみを設けるか、あるいは二つの電子源を設け、いずれか一方だけを使用する方法がとられてきた。しかし、使用する陰極を高速に切り替えることが可能な冷陰極電子源の場合、使用する二つ以上の電子源を交互に、選択的に、あるいは連続して切り替えることが可能になるため、複数の電子源をガラス管や金属筐体の中に配置し駆動するのに適した構造が求められる。 In both cases of "open type" and "closed type", even if a plurality of thermionic sources such as filaments used in the cathode of the conventional X-ray source are provided, switching of the thermionic source to be used is performed. Since it is impossible to perform the scanning at high speed, a method has been adopted in which only one electron source is provided or two electron sources are provided and only one of them is used. However, in the case of a cold cathode electron source capable of rapidly switching the cathode to be used, two or more electron sources to be used can be alternately, selectively, or continuously switched. A structure suitable for arranging and driving the electron source in a glass tube or a metal housing is required.
　さらに、冷陰極電子源そのものについては、図４に示すような、モリブデンなどの金属からなる微細な円錐状のエミッタから、その周囲の孔状のゲート電極が作る電界によって電子を真空中に引き出す「スピント型」や、図５に示すような、カーボンナノチューブの先端から電子を引き出す「ＣＮＴ型」が一般的であるが、いずれもひとつの冷陰極電子源から出る一本の電子ビームは、多数のエミッタやカーボンナノチューブから出る電子によって形成される。現在、「開放型」「密閉型」いずれのＸ線源においても、熱電子源の電子ビーム断面の電流分布を均一化することにより、陽極ターゲットが溶融することなく、できるだけ大きな電流を投入できるように、電子源の形状や周辺機構の工夫がこらされている。この電子ビーム断面の電流分布の制御は、冷陰極電子源において、一本の電子ビームを構成する多数のエミッタやカーボンナノチューブの形状や位置などを調整することによって、より直接的に行うことが可能になる。 Furthermore, as for the cold cathode electron source itself, as shown in FIG. 4, electrons are drawn into a vacuum from a fine conical emitter made of a metal such as molybdenum by an electric field created by a peripheral gate electrode. A Spindt-type or a CNT-type, as shown in FIG. 5, in which electrons are extracted from the tip of a carbon nanotube, is generally used. It is formed by electrons emitted from the emitter and carbon nanotube. At present, in both the "open" and "closed" X-ray sources, the current distribution in the electron beam cross section of the thermionic source is made uniform so that the largest possible current can be supplied without melting the anode target. In addition, the shape of the electron source and the peripheral mechanism have been devised. This control of the current distribution in the cross section of the electron beam can be performed more directly by adjusting the shape and position of many emitters and carbon nanotubes that constitute one electron beam in the cold cathode electron source. become.
　図４は、冷陰極電子源のひとつである「スピント型」のＸ線源を示す模式図である。スピント型の冷陰極電子源においては、モリブデンなどの金属からなる微細な円錐４ｅとそれを円周上に取り囲む、引き出し電極であるゲート４ｇの組が平面状に多数配置される。ゲート４ｇに電圧を印加すると円錐４ｅの先端から電子が放出され、これが陽極４ｂに衝突してＸ線を発生させる。ひとつのＸ線放射範囲には、通常１００以上の円錐３ｅから放出された電子が衝突するよう設計される。 FIG. 4 is a schematic view showing a "Spindt-type" X-ray source which is one of the cold cathode electron sources. In the Spindt-type cold cathode electron source, a large number of sets of a fine cone 4e made of a metal such as molybdenum and a gate 4g as a lead electrode surrounding the cone 4e on the circumference thereof are arranged in a large number. When a voltage is applied to the gate 4g, electrons are emitted from the tip of the cone 4e and collide with the anode 4b to generate X-rays. One X-ray emission range is usually designed to collide with electrons emitted from more than 100 cones 3e.
　図５は、別の冷陰極電子源である「ＣＮＴ型」のＸ線源を示す模式図である。ＣＮＴ型のＸ線源においては、微細な先端を持つ多数のカーボンナノチューブ５ｅを導電性のバインダー５ｆで固定し、陽極５ｂとカーボンナノチューブ５ｅの間に引き出し電極であるメッシュ電極５ｇを配置することが一般的である。メッシュ電極５ｇに電圧を印加するとカーボンナノチューブ５ｅの先端から電子が放出され、メッシュ電極５ｇを通過した電子が陽極５ｂに衝突してＸ線を発生させる。ひとつのＸ線放射範囲に対応するカーボンナノチューブ５ｅの先端は、通常１００以上である。 FIG. 5 is a schematic diagram showing a “CNT type” X-ray source which is another cold cathode electron source. In the CNT type X-ray source, it is possible to fix a large number of carbon nanotubes 5e having fine tips with a conductive binder 5f, and arrange a mesh electrode 5g as an extraction electrode between the anode 5b and the carbon nanotube 5e. General. When a voltage is applied to the mesh electrode 5g, electrons are emitted from the tip of the carbon nanotube 5e, and the electrons passing through the mesh electrode 5g collide with the anode 5b to generate X-rays. The tip of the carbon nanotube 5e corresponding to one X-ray emission range is usually 100 or more.
　本発明の第１の目的は、Ｘ線源をモジュール構造とすることによって冷陰極電子源の交換を可能とし、冷陰極電子源を用いたＸ線源の製造・保守を容易にすることである。 A first object of the present invention is to make it possible to replace a cold cathode electron source by making the X-ray source into a modular structure and to facilitate manufacture and maintenance of the X-ray source using the cold cathode electron source. .
　本発明の第２の目的は、三つ以上の冷陰極電子源を備えたＸ線源において、冷陰極電子源を挿入するために設けられた真空容器の開口部をより小型とすることである。 A second object of the present invention is to make an opening of a vacuum vessel provided for inserting a cold cathode electron source smaller in an X-ray source having three or more cold cathode electron sources. .
　本発明の第３の目的は、三つ以上の冷陰極電子源を備えたＸ線源において、真空容器から外部に引き出す配線の本数を少なくすることである。 第 A third object of the present invention is to reduce the number of wirings drawn out of a vacuum vessel to the outside in an X-ray source having three or more cold cathode electron sources.
　本発明の第４の目的は、三つ以上の冷陰極電子源を備えたＸ線源において、陽極のＸ線発生範囲（Ｘ線焦点）における電子衝突密度をより均一にすることである。 A fourth object of the present invention is to make the electron collision density in the X-ray generation range (X-ray focal point) of the anode more uniform in an X-ray source having three or more cold cathode electron sources.
　本発明の一側面によるＸ線発生装置は、開口を有する真空容器と、少なくとも一部が真空容器の内部に位置する陽極と、真空容器に対して着脱自在であり、開口を閉塞するよう真空容器に固定されたフランジと、フランジに固定され、真空容器の内部に位置する冷陰極電子源を含む陰極とを備える。 An X-ray generator according to one aspect of the present invention includes a vacuum vessel having an opening, an anode at least partially located inside the vacuum vessel, and a vacuum vessel detachable from the vacuum vessel and closing the opening. And a cathode including a cold cathode electron source fixed to the flange and located inside the vacuum vessel.
　冷陰極電子源は、所定の方向に延在する架台に複数配列されており、フランジに対する架台の接続点は、架台の所定の方向における中心部からオフセットした位置に設けられ、開口の径は、架台の所定の方向における長さよりも小さくても構わない。これによれば、冷陰極電子源を挿入するために設けられた真空容器の開口部をより小型とすることが可能となる。 A plurality of cold cathode electron sources are arranged on a gantry extending in a predetermined direction, a connection point of the gantry with respect to the flange is provided at a position offset from a center portion of the gantry in a predetermined direction, and a diameter of the opening is It may be smaller than the length of the gantry in a predetermined direction. According to this, the opening of the vacuum container provided for inserting the cold cathode electron source can be made smaller.
　冷陰極電子源は、複数の微細先端と、複数の微細先端にそれぞれ対応する複数の引き出し電極を有し、複数の微細先端の一部または複数の引き出し電極の一部には、共通の配線が割り当てられていても構わない。これによれば、真空容器から外部に引き出す配線の本数を少なくすることが可能となる。 The cold cathode electron source has a plurality of fine tips and a plurality of extraction electrodes respectively corresponding to the plurality of fine tips, and a common wiring is formed on a part of the plurality of fine tips or a part of the plurality of extraction electrodes. It may be assigned. According to this, it is possible to reduce the number of wires drawn out from the vacuum container.
　冷陰極電子源を複数備え、複数の冷陰極電子源は、それぞれ複数の電極を有する電子ビーム収束機構を備え、異なる冷陰極電子源に属する複数の電極には、共通の配線が割り当てられていても構わない。これによれば、真空容器から外部に引き出す配線の本数を少なくすることが可能となる。 A plurality of cold cathode electron sources are provided, each of the plurality of cold cathode electron sources includes an electron beam focusing mechanism having a plurality of electrodes, and a plurality of electrodes belonging to different cold cathode electron sources are assigned a common wiring. No problem. According to this, it is possible to reduce the number of wires drawn out from the vacuum container.
　本発明の一側面による冷陰極電子源は、複数の微細先端を有する冷陰極電子源であって、複数の微細先端は、中央領域に配置された第１のグループと、中央領域を囲む周縁領域に配置された第２のグループを含み、第２のグループから放出される電子ビームの単位面積当たりの電流量は、第１のグループから放出される電子ビームの単位面積当たりの電流量よりも大きい。 A cold cathode electron source according to one aspect of the present invention is a cold cathode electron source having a plurality of fine tips, wherein the plurality of fine tips have a first group disposed in a central region and a peripheral region surrounding the central region. And the amount of current per unit area of the electron beam emitted from the second group is larger than the amount of current per unit area of the electron beam emitted from the first group. .
　本発明の一側面によるＸ線発生装置によれば、Ｘ線源の製造・保守が容易となる。 According to the X-ray generator according to one aspect of the present invention, manufacture and maintenance of the X-ray source are facilitated.
　本発明の一側面による冷陰極電子源によれば、陽極のＸ線発生範囲（Ｘ線焦点）における電子衝突密度がより均一となる。 According to the cold cathode electron source according to one aspect of the present invention, the electron collision density in the X-ray generation range (X-ray focus) of the anode becomes more uniform.
図１は、ガラス管１ａを真空容器に用いる「密閉型」Ｘ線管の模式図である。FIG. 1 is a schematic diagram of a "sealed" X-ray tube using a glass tube 1a for a vacuum vessel. 図２は、金属筐体２ａを真空容器に用いる「密閉型」Ｘ線管の模式図である。FIG. 2 is a schematic diagram of a "sealed" X-ray tube using the metal housing 2a as a vacuum container. 図３は、「開放型」Ｘ線管の模式図である。FIG. 3 is a schematic diagram of an “open” X-ray tube. 図４は、冷陰極電子源のひとつである「スピント型」のＸ線源を示す模式図である。FIG. 4 is a schematic diagram showing a "Spindt-type" X-ray source which is one of the cold cathode electron sources. 図５は、別の冷陰極電子源である「ＣＮＴ型」のＸ線源を示す模式図である。FIG. 5 is a schematic diagram showing a “CNT type” X-ray source which is another cold cathode electron source. 図６は、本発明の第１の実施形態によるＸ線源の構造を示す模式図である。FIG. 6 is a schematic diagram showing the structure of the X-ray source according to the first embodiment of the present invention. 図７は、本発明の第２の実施形態によるＸ線源の陰極周辺の構造を示す模式図である。FIG. 7 is a schematic diagram showing the structure around the cathode of the X-ray source according to the second embodiment of the present invention. 図８は、「スピント型」冷陰極電子源において、三つ以上の冷陰極電子源の陰極と引き出し電極の導線の接続方法を示す模式図である。FIG. 8 is a schematic diagram showing a method of connecting the cathodes of three or more cold cathode electron sources and the lead wires of the extraction electrodes in the “Spindt type” cold cathode electron source. 図９は、本発明の第３の実施形態によるＸ線源の動作について説明するための模式図である。FIG. 9 is a schematic diagram for explaining the operation of the X-ray source according to the third embodiment of the present invention. 図１０は、冷陰極電子源を用いたＸ線源において、複数の微細先端から出る電子を集合して一本の電子ビームとして使用する場合の、電子ビーム断面の電流分布を説明するための模式図である。FIG. 10 is a schematic view for explaining a current distribution in a cross section of an electron beam when an electron emitted from a plurality of fine tips is used as one electron beam in an X-ray source using a cold cathode electron source. FIG. 図１１は、電子衝突密度をより均一とする第１の方法を説明するための模式図である。FIG. 11 is a schematic diagram for explaining a first method for making the electron collision density more uniform. 図１２は、電子衝突密度をより均一とする第２の方法を説明するための模式図である。FIG. 12 is a schematic diagram for explaining a second method for making the electron collision density more uniform.
　以下、添付図面を参照しながら、本発明の好ましい実施形態について詳細に説明する。 Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
＜第１の実施形態＞
　図６は、本発明の第１の実施形態によるＸ線源の構造を示す模式図である。第１の実施形態によるＸ線源は「密閉型」Ｘ線源であり、真空容器６ａを備える。真空容器６ａは、ガラスまたはセラミックからなる筒状筐体６ａ１と金属筐体６ａ２からなり、その内部には１つ又は２つの冷陰極電子源６ｅと収束電極６ｆが封入される。冷陰極電子源６ｅ及び収束電極６ｆは、導線６ｇを介して真空容器６ａの外部に接続される。筒状筐体６ａ１には陽極６ａ３が固定される。 <First embodiment>
FIG. 6 is a schematic diagram showing the structure of the X-ray source according to the first embodiment of the present invention. The X-ray source according to the first embodiment is a “sealed” X-ray source and comprises a vacuum vessel 6a. Vacuum container 6a is made cylindrical casing 6a 1 and the metal casing 6a 2 made of glass or ceramic, in its interior one or two cold-cathode electron source 6e and the focus electrode 6f is enclosed. The cold cathode electron source 6e and the focusing electrode 6f are connected to the outside of the vacuum vessel 6a via a conductive wire 6g. An anode 6a 3 is fixed to the cylindrical casing 6a 1.
　金属筐体６ａ２は、製造時において真空排気するための真空ポンプ接続部６ｂと、リング状の金属フランジ６ｃが接続される開口６ｄと、Ｘ線を外部に照射するための開口６ｈを備える。真空ポンプ接続部６ｂはガラスまたはセラミックからなり、製造段階においては真空ポンプに接続され、真空容器６ａの内部がほぼ真空となるまで排気された後、封止される。金属フランジ６ｃは、シーリングリング ６ｃ１を介して金属筐体６ａ２に接続され、ボルト６ｃ２などを用いて金属筐体６ａ２に固定される。リング状の金属フランジ６ｃに囲まれた領域には絶縁体６ｃ３が設けられている。冷陰極電子源６ｅや収束電極６ｆに接続された導線６ｇは、絶縁体６ｃ３を貫通して外部に引き出される。金属フランジ６ｃと絶縁体６ｃ３の隙間や、絶縁体６ｃ３と導線ｇの隙間は、ロウ付けなどにより封止される。これにより、真空容器６ａの内部は、半永久的に気密が確保される。 The metal housing 6a 2 is provided with a vacuum pump connection 6b for evacuating during manufacture, and the opening 6d of the ring-shaped metal flange 6c are connected, the aperture 6h for irradiating X-rays to the outside. The vacuum pump connection portion 6b is made of glass or ceramic, is connected to a vacuum pump in a manufacturing stage, and is evacuated until the inside of the vacuum container 6a becomes substantially vacuum, and then sealed. Metal flange 6c is connected to the metal casing 6a 2 via a sealing ring 6c 1, it is fixed to the metal housing 6a 2 by using a bolt 6c 2. The region surrounded by the ring-shaped metal flange 6c is provided an insulator 6c 3. Connected wire 6g cold cathode electron source 6e and focusing electrode 6f are drawn out through the insulator 6c 3. Gaps or metal flanges 6c and the insulator 6c 3, gap insulator 6c 3 and conductor g is sealed by such as brazing. Thereby, the inside of the vacuum container 6a is semi-permanently sealed.
　第１の実施形態によるＸ線源は、「密閉型」Ｘ線源であって、少なくとも製造中に陰極部分の交換が可能とされている。 The X-ray source according to the first embodiment is a “sealed” X-ray source, in which the cathode part can be replaced at least during manufacture.
　まず、本実施形態によるＸ線源を製造する過程で、真空ポンプ接続部６ｂを封止する前に冷陰極電子源６ｅを含む陰極に不具合が発見された場合は、金属フランジ６ｃを外して新たな陰極を搭載した金属フランジ６ｃに交換することにより、陰極以外の部材を流用することができる。また、本実施形態によるＸ線源の製造が完了し、真空ポンプ接続部６ｂを封止した後であっても、金属フランジ６ｃを開放して新たな陰極を搭載した金属フランジ６ｃに交換することができる。この場合、真空ポンプ接続部６ｂを開封し、真空ポンプを用いて真空容器６ａの内部がほぼ真空となるまで排気した後、再び封止すればよい。 First, in the process of manufacturing the X-ray source according to the present embodiment, if a defect is found in the cathode including the cold cathode electron source 6e before sealing the vacuum pump connection 6b, the metal flange 6c is removed and a new one is removed. By replacing the metal flange 6c with a suitable cathode, members other than the cathode can be used. Further, even after the manufacture of the X-ray source according to the present embodiment is completed and the vacuum pump connection portion 6b is sealed, the metal flange 6c is opened and replaced with a metal flange 6c on which a new cathode is mounted. Can be. In this case, the vacuum pump connection portion 6b may be opened, the inside of the vacuum container 6a may be evacuated using a vacuum pump until the inside of the vacuum container 6a becomes substantially vacuum, and then sealed again.
　このように、本実施形態によるＸ線源は、冷陰極電子源６ｅ及び収束電極６ｆからなる陰極を交換可能に構成されていることから、陰極に不具合が発生した場合であっても、Ｘ線源の全体を廃棄する必要はなく、陰極部分のみを交換することが可能となる。また、フランジは金属製である必要はない。 As described above, the X-ray source according to the present embodiment is configured such that the cathode including the cold cathode electron source 6e and the focusing electrode 6f can be exchanged. It is not necessary to dispose of the entire source, only the cathode part can be replaced. Also, the flange need not be made of metal.
＜第２の実施形態＞
　図７（ａ）は、本発明の第２の実施形態によるＸ線源の陰極周辺の構造を示す模式図である。第２の実施形態によるＸ線源は、三つ以上の冷陰極電子源Ｅ１～Ｅｎを含んだ陰極を持つ「密閉型」Ｘ線源である。真空容器７ａ２は金属製であり、図６に示した方法と同じ方法を用いて、陰極と一体的に構成された金属フランジ７ｃと真空容器７ａ２が固定される。図７（ａ）に示す例では、１つの架台７ｊにｎ個（ｎは３以上）の冷陰極電子源Ｅ１～Ｅｎが直線上に配置されている。架台７ｊの長さは、金属筐体７ａ２に設けられた開口７ｄの径よりも大きい。このような架台７ｊを開口７ｄから金属筐体７ａ２の内部に挿入できるようにするため、金属フランジ７ｃに接続された支柱７ｃ４は、架台７ｊの端部に近い接続点７ｋに接続されている。また、図７（ａ）に示す構造体を図７（ｂ）に示すように複数並べることにより、より多くの冷陰極電子源を金属筐体７ａ２の内部に配列しても構わない。図７（ｂ）に示す例では、３個の金属フランジ７ｃ１～７ｃ３と、３個の架台７ｊ１～７ｊ３が用いられており、これら架台７ｊ１～７ｊ３に設けられた冷陰極電子源のピッチは一定に保たれている。 <Second embodiment>
FIG. 7A is a schematic diagram showing the structure around the cathode of the X-ray source according to the second embodiment of the present invention. The X-ray source according to the second embodiment is a "sealed" X-ray source having a cathode including three or more cold cathode electron sources E1 to En. Vacuum vessel 7a 2 is made of metal, using the same method as shown in FIG. 6, the metal flange 7c and the vacuum chamber 7a 2 which are cathode and integrally formed is fixed. In the example shown in FIG. 7A, n (n is 3 or more) cold cathode electron sources E1 to En are linearly arranged on one mount 7j. The length of the gantry 7j is greater than the diameter of the opening 7d provided in the metal housing 7a 2. To such a gantry 7j from opening 7d to be inserted into the interior of the metal housing 7a 2, strut 7c 4 connected to the metal flange 7c is connected to the connection point 7k near the end of the gantry 7j I have. Further, a plurality arranging it as shown in FIG. 7 (b) the structure shown in FIG. 7 (a), may be more cold-cathode electron source arranged inside the metal enclosure 7a 2. In the example shown in FIG. 7B, three metal flanges 7c 1 to 7c 3 and three mounts 7j 1 to 7j 3 are used, and the cold cathodes provided on these mounts 7j 1 to 7j 3 are used. The pitch of the electron source is kept constant.
　図８（ａ）～（ｃ）は、「スピント型」冷陰極電子源において、三つ以上の冷陰極電子源の陰極と引き出し電極の導線の接続方法を示す模式図である。図８（ａ）に示す例では、冷陰極電子源Ｅ１～Ｅｎの陰極を全て共通の配線に接続する一方、引き出し電極については冷陰極電子源Ｅ１～Ｅｎに対してそれぞれ個別の配線に接続している。これにより、引き出し電極への電圧印加によって、１又は２以上の任意の冷陰極電子源Ｅ１～Ｅｎを駆動することができる。この場合、金属フランジ７ｃを通る導線の数はｎ＋１本となる。図８（ｂ）に示す例では、冷陰極電子源Ｅ１～Ｅｎの引き出し電極を全て共通の配線に接続する一方、陰極については冷陰極電子源Ｅ１～Ｅｎに対してそれぞれ個別の配線に接続している。これにより、陰極への電圧印加によって、１又は２以上の任意の冷陰極電子源Ｅ１～Ｅｎを駆動することができる。この場合も、金属フランジ７ｃを通る導線の数はｎ＋１本となる。図８（ｃ）に示す例では、冷陰極電子源Ｅ１～Ｅｎのそれぞれにリレー回路８Ｌ１～８Ｌｎを接続し、これらを制御する制御回路８ｍを設ける。この場合、金属フランジを通る導線は、印加電圧の電源と制御回路８ｍの制御信号線のみとなる。 FIGS. 8 (a) to 8 (c) are schematic views showing a connection method between the cathodes of three or more cold cathode electron sources and the lead wires of the extraction electrodes in the "Spindt type" cold cathode electron source. In the example shown in FIG. 8A, the cathodes of the cold cathode electron sources E1 to En are all connected to a common wiring, while the extraction electrodes are connected to individual wirings for the cold cathode electron sources E1 to En. ing. Thus, one or more arbitrary cold cathode electron sources E1 to En can be driven by applying a voltage to the extraction electrode. In this case, the number of conducting wires passing through the metal flange 7c is n + 1. In the example shown in FIG. 8B, all the extraction electrodes of the cold cathode electron sources E1 to En are connected to a common wiring, while the cathode is connected to individual wirings for the cold cathode electron sources E1 to En. ing. Thereby, one or more arbitrary cold cathode electron sources E1 to En can be driven by applying a voltage to the cathode. Also in this case, the number of conducting wires passing through the metal flange 7c is n + 1. In the example shown in FIG. 8C, relay circuits 8L1 to 8Ln are connected to the cold cathode electron sources E1 to En, respectively, and a control circuit 8m for controlling these is provided. In this case, the conductor passing through the metal flange is only the power source of the applied voltage and the control signal line of the control circuit 8m.
　第２の実施形態によるＸ線源は、三つ以上の冷陰極電子源を含んだ陰極を持つ「密閉型」Ｘ線源であって、少なくとも製造中に、陰極部分の交換が可能に構成されている。基本的な構成要素及び使用方法は、第１の実施形態によるＸ線源と同じである。但し、第１の実施形態によるＸ線源とは異なり、第２の実施形態によるＸ線源は三つ以上の冷陰極電子源を備えていることから、冷陰極電子源全体の寸法が大きくなる。しかしながら、冷陰極電子源を真空容器７ａ２に挿入するための開口７ｄの径をそのまま大型化すると、真空を保持する上で好ましくない。この問題を解決するため、第２の実施形態によるＸ線源は、３以上の冷陰極電子源を架台７ｊに直線上に配列し、架台７ｊの一方の端部、つまり、架台７ｊの中心部からオフセットした位置に接続点７ｋを設けることによって、より小径の開口７ｄを用いることができる。 The X-ray source according to the second embodiment is a "sealed" X-ray source having a cathode containing three or more cold cathode electron sources, wherein at least during manufacture the cathode part can be replaced. ing. The basic components and the method of use are the same as those of the X-ray source according to the first embodiment. However, unlike the X-ray source according to the first embodiment, the X-ray source according to the second embodiment includes three or more cold cathode electron sources, so that the overall size of the cold cathode electron source increases. . However, when it is enlarging the diameter of the opening 7d for inserting the cold cathode electron source in the vacuum chamber 7a 2, not preferable to hold the vacuum. In order to solve this problem, the X-ray source according to the second embodiment has three or more cold cathode electron sources arranged in a straight line on the gantry 7j, and has one end of the gantry 7j, that is, the center of the gantry 7j. By providing the connection point 7k at a position offset from, the opening 7d having a smaller diameter can be used.
　また、冷陰極電子源の数がｎ個の場合、それぞれの陰極と引き出し電極を全て個別に配線すると、２×ｎ本の導線が必要となる。しかしながら、図８（ａ）に示すように、陰極に接続された配線を共通にし、引き出し電極に接続された配線を個別にする、或いは、図８（ｂ）に示すように、陰極に接続された配線を個別にし、引き出し電極に接続された配線を共通にすれば、配線の本数をｎ＋１本に節約することができる。また、図８（ｃ）に示すように、陰極あるいは引き出し電極に印加する電圧を個別に制御する制御回路８ｍを真空容器７ａ２の内部に配置しても構わない。 When the number of the cold cathode electron sources is n, if all the cathodes and the extraction electrodes are individually wired, 2 × n conductors are required. However, as shown in FIG. 8A, the wiring connected to the cathode is made common, and the wiring connected to the extraction electrode is made individual, or as shown in FIG. If the wirings connected to the extraction electrode are made common and the wirings connected to the extraction electrode are made common, the number of wirings can be reduced to n + 1. Further, as shown in FIG. 8 (c), may be disposed a control circuit 8m for controlling a voltage applied to the cathode or the extraction electrode individually in the vacuum chamber 7a 2.
＜第３の実施形態＞
　図９は、本発明の第３の実施形態によるＸ線源の動作について説明するための模式図である。第３の実施形態によるＸ線源は、三つ以上の冷陰極電子源を含み、電極ｐ、ｑ、ｒに印加する電圧によって、電子ビームの形状や方向を制御することが可能である。冷陰極電子源としては「スピント型」を前提としている。ｎ個の冷陰極電子源Ｅ１～Ｅｎの電子源には、それぞれ電子ビーム収束機構の３つの電極ｐ、ｑ、ｒが割り当てられている（Ｍ＝３）。これらの電極ｐ、ｑ、ｒを用いた電子ビームの収束方法は、電界によるか磁界によるかを問わない。 <Third embodiment>
FIG. 9 is a schematic diagram for explaining the operation of the X-ray source according to the third embodiment of the present invention. The X-ray source according to the third embodiment includes three or more cold cathode electron sources, and the shape and direction of the electron beam can be controlled by the voltage applied to the electrodes p, q, and r. As a cold cathode electron source, a "Spindt type" is assumed. Each of the n cold cathode electron sources E1 to En is assigned three electrodes p, q, and r of the electron beam focusing mechanism (M = 3). A method of converging an electron beam using these electrodes p, q, and r does not matter whether an electric field or a magnetic field is used.
　図９（ａ）に示す例では、電極ｐ１～ｐｎ、電極ｑ１～ｑｎ、電極ｒ１～ｒｎをそれぞれ共通の配線に接続している。このため、稼働している電子源以外の電子源についても同じ収束条件がもたらされる。もちろん、稼働していない電子源には影響がない。ｎ個の冷陰極電子源にそれぞれ設けられた電極ｐ、ｑ、ｒを全て別個の配線に接続すると、Ｍ×ｎ本の配線が必要となるが、図９（ａ）に示す例ではＭ本の配線で足りる。 In the example shown in FIG. 9A, the electrodes p1 to pn, the electrodes q1 to qn, and the electrodes r1 to rn are connected to a common wiring. Therefore, the same convergence condition is provided for electron sources other than the active electron source. Of course, inactive electron sources have no effect. When all of the electrodes p, q, and r provided on the n cold cathode electron sources are connected to separate wirings, M × n wirings are required. In the example shown in FIG. Wiring is enough.
　図９（ｂ）に示す例では、ｎ個の冷陰極電子源Ｅ１～Ｅｎをいくつかのグループ（本例では２グループ）に分け、グループごとに、電極ｐ、ｑ、ｒを共通の配線に接続している。例えば、冷陰極電子源Ｅ１とＥｎは同じグループに属しているため、電極ｐ１、ｐｎは共通の配線に接続され、電極ｑ１，ｑｎは共通の配線に接続され、電極ｒ１、ｒｎは共通の配線に接続されている。また、冷陰極電子源Ｅ２とＥ３は別のグループに属しているため、電極ｐ２、ｐ３は共通の配線に接続され、電極ｑ２、ｑ３は共通の配線に接続され、電極ｒ２、ｒ３は共通の配線に接続されている。図９（ｂ）に示す例は、複数の電子源を同時に稼働する必要がある場合などに有用である。 In the example shown in FIG. 9B, the n cold cathode electron sources E1 to En are divided into several groups (two groups in this example), and the electrodes p, q, and r are shared by common wiring for each group. Connected. For example, since the cold cathode electron sources E1 and En belong to the same group, the electrodes p1 and pn are connected to a common line, the electrodes q1 and qn are connected to a common line, and the electrodes r1 and rn are connected to a common line. It is connected to the. Further, since the cold cathode electron sources E2 and E3 belong to different groups, the electrodes p2 and p3 are connected to a common wiring, the electrodes q2 and q3 are connected to a common wiring, and the electrodes r2 and r3 are connected to a common wiring. Connected to wiring. The example shown in FIG. 9B is useful when it is necessary to operate a plurality of electron sources simultaneously.
　図９（ｃ）に示す例では、各冷陰極電子源Ｅ１～Ｅｎの収束機構のそれぞれにリレー回路９Ｌ１～９Ｌｎを接続し、これらを制御する制御回路９ｍを設けて、全ての収束機構を独立に駆動できるようにしている。制御回路９ｍは、真空容器の内部に位置するよう、陰極の近傍に配置すれば、真空容器を貫通する配線の本数を大幅に削減することが可能となる。 In the example shown in FIG. 9C, relay circuits 9L1 to 9Ln are connected to the convergence mechanisms of the cold cathode electron sources E1 to En, respectively, and a control circuit 9m for controlling these is provided. Can be driven. If the control circuit 9m is arranged near the cathode so as to be located inside the vacuum vessel, it is possible to greatly reduce the number of wires penetrating the vacuum vessel.
＜第４の実施形態＞
　図１０は、冷陰極電子源を用いたＸ線源において、複数の微細先端から出る電子を集合して一本の電子ビームとして使用する場合の、電子ビーム断面の電流分布を説明するための模式図である。ひとつの微細先端１０ｅ０から出る電子は、陽極ターゲット１０ｂ上の一定の範囲ｔ０に衝突し、衝突した場所において、衝突した電子数に応じた熱とＸ線が放射される。衝突する電子の密度分布はｓ０である。電子が衝突する範囲ｔ０の位置は、微細先端１０ｅ０の位置によって決まり、全ての微細先端１０ｅ０からの電子（電子ビーム）を合計すると、範囲Ｔにおける電子の密度分布はＳとなる。この密度分布Ｓは、陽極ターゲット１０ｂ上の発熱分布と、ここから発生するＸ線発生分布に対応する。ここで得られるＸ線量をＴｘの範囲でＸｓとする。陽極ターゲット１０ｂ上のある範囲から所定のＸ線量を照射することが必要な場合、当該範囲に衝突する電子数は当該範囲内で均一であるほど好ましい。これは、電子衝突密度が局所的に高い部分が存在すると、その部分が高熱となり、陽極ターゲット１０ｂが溶融する恐れがあるからである。したがって、Ｘ線発生範囲（Ｘ線焦点）においては、電子衝突密度ができるだけ均一であることが好ましい。 <Fourth embodiment>
FIG. 10 is a schematic view for explaining a current distribution in a cross section of an electron beam when an electron emitted from a plurality of fine tips is used as one electron beam in an X-ray source using a cold cathode electron source. FIG. One of electrons exiting the micro-tip 10e 0 collides with a certain range t0 on the anode target 10b, in the collision location, collided heat and X-rays corresponding to the number of electrons are emitted. The density distribution of the colliding electrons is s0. Position ranges t0 to electron collision is determined by the position of the fine tip 10e 0, when the sum of the electron (electron beam) from all the fine tip 10e 0, the density distribution of electrons in the region T becomes S. This density distribution S corresponds to the heat generation distribution on the anode target 10b and the X-ray generation distribution generated therefrom. The X-ray dose obtained here is defined as Xs in the range of Tx. When it is necessary to irradiate a predetermined X-ray dose from a certain range on the anode target 10b, it is preferable that the number of electrons colliding with the certain range be uniform within the range. This is because if there is a portion where the electron collision density is locally high, the portion becomes high heat and the anode target 10b may be melted. Therefore, it is preferable that the electron collision density is as uniform as possible in the X-ray generation range (X-ray focal point).
　Ｘ線発生範囲（Ｘ線焦点）における電子衝突密度をより均一にする方策の一つとして、図１１に示す方法が挙げられる。図１１に示す例は、冷陰極電子源の微細先端が多数存在し、その配置を調整するものである。すなわち、陽極ターゲット１１ｂ上の電子衝突範囲の中心部で電子密度が粗に、周縁部で電子密度が密になるよう、冷陰極電子源の微細先端の密度を、中心部で粗に、周縁部で密に配置するようにする。 As one of the measures to make the electron collision density more uniform in the X-ray generation range (X-ray focal point), there is a method shown in FIG. In the example shown in FIG. 11, there are many fine tips of the cold cathode electron source, and the arrangement is adjusted. That is, the density of the fine tip of the cold cathode electron source is coarsely adjusted at the central portion and the peripheral portion is reduced so that the electron density becomes coarse at the center of the electron collision range on the anode target 11b and the electron density becomes dense at the peripheral portion. To be densely arranged.
　図１１（ａ）に示す例は、第４の実施形態によるＸ線源において、電子ビーム断面の電流分布Ｓを制御するものである。微細先端１１ｅ０～１１ｅ４のうち、微細先端１１ｅ０は範囲Ｔの中央部に電子ビームを照射するものであり、微細先端１１ｅ３、１１ｅ４は範囲Ｔの周縁部に電子ビームを照射するものであり、微細先端１１ｅ１、１１ｅ２は範囲Ｔの中央部と周縁部の間に電子ビームを照射するものである。そして、第４の実施形態では、微細先端１１ｅ０～１１ｅ４の間隔が微細先端１１ｅ１～１１ｅ３間、１１ｅ２～１１ｅ４間では狭く、微細先端１１ｅ０～１１ｅ１間、１１ｅ０～１１ｅ２間では広い。これにより、微細先端１１ｅ０～１１ｅ４から放出される電子が陽極ターゲットの範囲Ｔに衝突する密度分布Ｓ'は、図１１（ａ）に示すように、中心部と周縁部の差が小さくなる。つまり、電流量及び範囲Ｔが変わらなくても、密度分布Ｓ'における最高密度は密度分布Ｓにおける最高密度よりも小さくなり、密度分布Ｓ'の急峻度をより緩やかにすることができる。このとき範囲Ｔｘにおいて得られるＸ線量Ｘｓ'は図１０におけるＸ線量Ｘｓよりも大きくなる。図１１（ｂ）は、同様の構成をカーボンナノチューブで実現する方法を示している。 The example shown in FIG. 11A controls the current distribution S in the cross section of the electron beam in the X-ray source according to the fourth embodiment. Among the fine tips 11e 0 to 11e 4 , the fine tip 11e 0 irradiates the electron beam to the central part of the range T, and the fine tips 11e 3 and 11e 4 irradiates the peripheral part of the range T to the electron beam. The fine tips 11e 1 and 11e 2 irradiate an electron beam between a central portion and a peripheral portion of the range T. In the fourth embodiment, the distance between the fine tips 11e 0 to 11e 4 is narrow between the fine tips 11e 1 to 11e 3 and between the fine tips 11e 2 to 11e 4, and the distance between the fine tips 11e 0 to 11e 1 and 11e 0 to 11e. Wide between the two . As a result, in the density distribution S ′ where electrons emitted from the fine tips 11e 0 to 11e 4 collide with the range T of the anode target, as shown in FIG. 11A, the difference between the center part and the peripheral part becomes smaller. . That is, even if the current amount and the range T do not change, the highest density in the density distribution S 'becomes smaller than the highest density in the density distribution S, and the steepness of the density distribution S' can be made gentler. At this time, the X-ray dose Xs ′ obtained in the range Tx is larger than the X-ray dose Xs in FIG. FIG. 11B shows a method for realizing a similar configuration with carbon nanotubes.
　Ｘ線発生範囲（Ｘ線焦点）における電子衝突密度をより均一にする別の方策として、図１２に示す方法が挙げられる。図１２に示す例は、微細先端ごとに電子放出量を調整するものであり、微細先端の場所ごとに異なる引き出し電圧を印加する方法、微細先端の場所ごとに引き出し電圧が調整されるような回路を組み込む方法、微細先端が場所ごとに異なる電子放出効率を取るように製作する方法が挙げられる。 Another method for making the electron collision density more uniform in the X-ray generation range (X-ray focus) is the method shown in FIG. The example shown in FIG. 12 is for adjusting the amount of electron emission for each fine tip, a method of applying a different extraction voltage for each location of the fine tip, and a circuit for adjusting the extraction voltage for each location of the fine tip. And a method in which the fine tip is manufactured so as to have different electron emission efficiencies at different locations.
　図１２（ａ）～（ｃ）は、「スピント型」冷陰極電子源を前提として、微細先端の配列ピッチを一定としつつ、電流分布Ｓを制御する方法を示す模式図である。図１２（ａ）～（ｃ）においては、中央領域に複数の微細先端１２ｅ１が配置され、周縁領域に複数の微細先端１２ｅ３が配置され、その中間領域に複数の微細先端１２ｅ２が配置されている。 FIGS. 12A to 12C are schematic diagrams showing a method of controlling the current distribution S while keeping the arrangement pitch of the fine tips constant on the premise of the “Spindt” cold cathode electron source. Figure in 12 (a) ~ (c) , a plurality of micro-tip 12e 1 is arranged in the central area, it is arranged a plurality of fine tip 12e 3 to the peripheral region, a plurality of micro-tip 12e 2 is disposed in the middle region Have been.
　図１２（ａ）に示す例では、電子が範囲Ｔの中心部に衝突する中央領域に配置された微細先端１２ｅ１には低い電圧を印加し、電子が範囲Ｔの周縁部に衝突する周縁領域に配置された微細先端１２ｅ３には高い電圧を印加する。図１２（ｂ１）に示す例では、抵抗Ｒ１を介して中央領域と中間領域を接続し、抵抗Ｒ２を介して周縁領域と中間領域を接続し、周縁領域に所定の電圧を印加する。これによれば、抵抗Ｒ１、Ｒ２による電圧降下によって、微細先端１２ｅ１には低い電圧が印加され、微細先端１２ｅ３には高い電圧が印加される。同様のことは、図１２（ｂ２）に示すように、陰極抵抗を微細先端１２ｅ１において低く、微細先端１２ｅ３において高くすることによっても実現できる。図１２（ｃ）に示す例では、微細先端１２ｅ１～１２ｅ３に同じ引き出し電圧を印加するが、中央領域に位置する微細先端１２ｅ１においては電子放出効率が低く、周縁領域に位置する微細先端１２ｅ３においては電子放出効率が高くなるよう、微細先端１２ｅ１～１２ｅ３の形状を設計する。具体的には、微細先端１２ｅ１～１２ｅ３からゲート電極までの距離を変えることによって電子放出効率を変化させることができる。 In the example shown in FIG. 12 (a), a low voltage is applied to the fine tip 12e 1 disposed in the central region where electrons collide with the central part of the range T, the peripheral region that impinges on the periphery of the electronic range T to apply a high voltage to a fine tip 12e 3 that placed on. In the example shown in FIG. 12B1, the central region and the intermediate region are connected via a resistor R1, the peripheral region and the intermediate region are connected via a resistor R2, and a predetermined voltage is applied to the peripheral region. According to this, the voltage drop due to the resistance R1, R2, is a lower voltage is applied to the fine tip 12e 1, a high voltage is applied to the fine tip 12e 3. The same, as shown in FIG. 12 (b2), a low cathode resistance in fine tip 12e 1, can also be achieved by increasing the fine tip 12e 3. In the example shown in FIG. 12C, the same extraction voltage is applied to the fine tips 12e 1 to 12e 3 , but the electron emission efficiency is low in the fine tip 12e 1 located in the central region, and the fine tips located in the peripheral region are low. so that the electron emission efficiency becomes higher in 12e 3, designing the shape of the fine tip 12e 1 ~ 12e 3. Specifically, the electron emission efficiency can be changed by changing the distance from the fine tips 12e 1 to 12e 3 to the gate electrode.
　いずれの方法においても、周縁領域に配置された微細先端１２ｅ３から放出される電子ビームの単位面積当たりの電流量は、中央領域に配置された微細先端１２ｅ１から放出される電子ビームの単位面積当たりの電流量よりも大きくなる。その結果、図１１に示すようによりフラットな密度分布Ｓ'を得ることが可能となる。 In either method, the current amount per unit area of the electron beam emitted from the fine tip 12e 3 disposed in the peripheral area, unit area of the electron beam emitted from the fine tip 12e 1 arranged in the central region It becomes larger than the current amount per hit. As a result, a flatter density distribution S ′ can be obtained as shown in FIG.
　以上、本発明の好ましい実施形態について説明したが、本発明は、上記の実施形態に限定されることなく、本発明の主旨を逸脱しない範囲で種々の変更が可能であり、それらも本発明の範囲内に包含されるものであることはいうまでもない。 As described above, the preferred embodiments of the present invention have been described. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist of the present invention. It goes without saying that they are included in the range.
１ａ　　ガラス管
１ａ１　　陽極側部分
１ａ２　　陰極側部分
１ｂ　　陽極
１ｃ　　陰極
１ｅ　　熱電子源
１ｆ　　収束電極
１ｇ　　導線
２ａ　　金属筐体
２ｂ　　陽極
２ｂ１　　絶縁素材
２ｃ　　陰極
２ｃ１　　絶縁素材
２ｇ　　導線
２ｈ　　開口
３ａ１　　金属筐体
３ａ２　　金属筐体
３ｂ　　陽極
３ｂ１　　絶縁体
３ｃ　　陰極
３ｅ　　熱電子源
３ｅ　　円錐
３ｇ　　導線
３ｈ　　Ｘ線開口
３ｉ　　真空ポンプ
４ｂ　　陽極
４ｅ　　円錐
４ｇ　　ゲート
５ｂ　　陽極
５ｅ　　カーボンナノチューブ
５ｆ　　バインダー
５ｇ　　メッシュ電極
６ａ　　真空容器
６ａ１　　筒状筐体
６ａ２　　金属筐体
６ａ３　　陽極
６ｂ　　真空ポンプ接続部
６ｃ　　金属フランジ
６ｃ２　　ボルト
６ｃ３　　絶縁体
６ｄ　　開口
６ｅ　　冷陰極電子源
６ｆ　　収束電極
６ｇ　　導線
６ｈ　　開口
７ａ２　　金属筐体
７ｃ　　金属フランジ
７ｃ４　　支柱
７ｄ　　開口
７ｊ　　架台
７ｊ１～７ｊ３　　架台
７ｋ　　接続点
８Ｌ１～８Ｌｎ　　リレー回路
８ｍ　　制御回路
９ｍ　　制御回路
１０ｂ　　陽極ターゲット
１０ｅ０　　微細先端
１１ｂ　　陽極ターゲット
１１ｅ０～１１ｅ４　　微細先端
１２ｅ１～１２ｅ３　　微細先端
Ｅ１～Ｅｎ　　冷陰極電子源
９Ｌ１～９Ｌｎ　　リレー回路
Ｒ１、Ｒ２　　抵抗
ｐ、ｑ、ｒ　　電極 1a Glass tube 1a 1 Anode side 1a 2 Cathode side 1b Anode 1c Cathode 1e Thermoelectron source 1f Focusing electrode 1g Conductor 2a Metal casing 2b Anode 2b 1 Insulating material 2c Cathode 2c 1 Insulating material 2g Conducting wire 2h Opening 3a 1 Metal casing Body 3a 2 Metal housing 3b Anode 3b 1 Insulator 3c Cathode 3e Thermionic source 3e Cone 3g Conductor 3h X-ray opening 3i Vacuum pump 4b Anode 4e Cone 4g Gate 5b Anode 5e Carbon nanotube 5f Binder 5g Mesh electrode 6a Vacuum container 6a 1 Cylindrical housing 6a 2 metal housing 6a 3 anode 6b vacuum pump connection 6c metal flange 6c 2 bolt 6c 3 insulator 6d opening 6e cold cathode electron source 6f focusing electrode 6g conducting wire 6h opening 7a 2 metal housing 7c metal flange 7c 4 pillars 7d opening 7j gantry 7j 1 to 7j 3 gantry 7k connection Points 8L1 to 8Ln Relay circuit 8m Control circuit 9m Control circuit 10b Anode target 10e 0 Fine tip 11b Anode target 11e 0 to 11e 4 Fine tip 12e 1 to 12e 3 Fine tip E1 to En Cold cathode electron sources 9L1 to 9Ln Relay circuit R1, R2 resistance p, q, r electrodes

Claims (5)

  1. 　開口を有する真空容器と、
    　少なくとも一部が前記真空容器の内部に位置する陽極と、
    　前記真空容器に対して着脱自在であり、前記開口を閉塞するよう前記真空容器に固定されたフランジと、
    　前記フランジに固定され、前記真空容器の内部に位置する冷陰極電子源を含む陰極と、を備えるＸ線発生装置。     A vacuum container having an opening,
    An anode at least partially located inside the vacuum vessel,
    A flange that is detachable from the vacuum container and fixed to the vacuum container so as to close the opening,
    A cathode fixed to the flange and including a cold cathode electron source located inside the vacuum vessel.
  2. 　前記冷陰極電子源は、所定の方向に延在する架台に複数配列されており、
    　前記フランジに対する前記架台の接続点は、前記架台の前記所定の方向における中心部からオフセットした位置に設けられ、
    　前記開口の径は、前記架台の前記所定の方向における長さよりも小さい、請求項１に記載のＸ線発生装置。     The cold cathode electron sources are arranged in a plurality on a gantry extending in a predetermined direction,
    A connection point of the gantry with respect to the flange is provided at a position offset from a center portion of the gantry in the predetermined direction,
    The X-ray generator according to claim 1, wherein a diameter of the opening is smaller than a length of the gantry in the predetermined direction.
  3. 　前記冷陰極電子源は、複数の微細先端と、前記複数の微細先端にそれぞれ対応する複数の引き出し電極を有し、
    　前記複数の微細先端の一部または前記複数の引き出し電極の一部には、共通の配線が割り当てられている、請求項１又は２に記載のＸ線発生装置。     The cold cathode electron source has a plurality of fine tips, and a plurality of extraction electrodes respectively corresponding to the plurality of fine tips,
    The X-ray generator according to claim 1, wherein a common wiring is assigned to a part of the plurality of fine tips or a part of the plurality of extraction electrodes.
  4. 　前記冷陰極電子源を複数備え、
    　前記複数の冷陰極電子源は、それぞれ複数の電極を有する電子ビーム収束機構を備え、
    　異なる冷陰極電子源に属する前記複数の電極には、共通の配線が割り当てられている、請求項１乃至３のいずれか一項に記載のＸ線発生装置。     Comprising a plurality of cold cathode electron sources,
    The plurality of cold cathode electron sources each include an electron beam focusing mechanism having a plurality of electrodes,
    The X-ray generator according to any one of claims 1 to 3, wherein a common wiring is assigned to the plurality of electrodes belonging to different cold cathode electron sources.
  5. 　複数の微細先端を有する冷陰極電子源であって、
    　前記複数の微細先端は、中央領域に配置された第１のグループと、前記中央領域を囲む周縁領域に配置された第２のグループを含み、
    　前記第２のグループから放出される電子ビームの単位面積当たりの電流量は、前記第１のグループから放出される電子ビームの単位面積当たりの電流量よりも大きい、冷陰極電子源。     A cold cathode electron source having a plurality of fine tips,
    The plurality of fine tips include a first group arranged in a central region and a second group arranged in a peripheral region surrounding the central region,
    A cold cathode electron source, wherein the amount of current per unit area of the electron beam emitted from the second group is larger than the amount of current per unit area of the electron beam emitted from the first group.
PCT/JP2019/024045 2018-06-22 2019-06-18 Cold cathode electron source and x-ray generator equipped with same WO2019244874A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US201862688513P 2018-06-22 2018-06-22
US62/688,513 2018-06-22

Publications (1)

Publication Number Publication Date
WO2019244874A1 true WO2019244874A1 (en) 2019-12-26

Family

ID=68983742

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2019/024045 WO2019244874A1 (en) 2018-06-22 2019-06-18 Cold cathode electron source and x-ray generator equipped with same

Country Status (1)

Country Link
WO (1) WO2019244874A1 (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06176686A (en) * 1992-12-10 1994-06-24 Fujitsu Ltd Field emission cathode device and manufacture thereof
JPH07182966A (en) * 1993-12-22 1995-07-21 Futaba Corp Field emission type electron source
JPH0950758A (en) * 1995-05-30 1997-02-18 Mitsubishi Electric Corp Electron source and manufacture thereof and manufacture of cathode-ray tube using the electron source
JP2017059360A (en) * 2015-09-15 2017-03-23 浜松ホトニクス株式会社 X-ray measurement apparatus, exchange method for electron beam source and electron gun
US20180005796A1 (en) * 2016-05-16 2018-01-04 Nanox Imaging Plc X-ray tube and a controller thereof

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06176686A (en) * 1992-12-10 1994-06-24 Fujitsu Ltd Field emission cathode device and manufacture thereof
JPH07182966A (en) * 1993-12-22 1995-07-21 Futaba Corp Field emission type electron source
JPH0950758A (en) * 1995-05-30 1997-02-18 Mitsubishi Electric Corp Electron source and manufacture thereof and manufacture of cathode-ray tube using the electron source
JP2017059360A (en) * 2015-09-15 2017-03-23 浜松ホトニクス株式会社 X-ray measurement apparatus, exchange method for electron beam source and electron gun
US20180005796A1 (en) * 2016-05-16 2018-01-04 Nanox Imaging Plc X-ray tube and a controller thereof

Similar Documents

Publication Publication Date Title
US8300769B2 (en) Microminiature X-ray tube with triode structure using a nano emitter
KR101901185B1 (en) X-ray device and ct equipment having x-ray device
US7359484B2 (en) Devices and methods for producing multiple x-ray beams from multiple locations
US7826595B2 (en) Micro-focus field emission x-ray sources and related methods
KR101855931B1 (en) X-ray device and ct equipment having same
JP6496321B2 (en) X-ray apparatus and CT device having the X-ray apparatus
EP2860751B1 (en) A X-Ray Apparatus and a CT device having the same
KR100766907B1 (en) X-ray tube system with disassembled carbon nanotube substrate for generating micro focusing level electron-beam
KR100895067B1 (en) The discretely addressable large area x-ray system
JP5845342B2 (en) X-ray tube and electron-emitting device for X-ray tube
CN109417008A (en) For generating the cathode assembly of X-ray
WO2019244874A1 (en) Cold cathode electron source and x-ray generator equipped with same
KR20160102744A (en) Field Emission X-Ray Source Device
JP2006086001A (en) X-ray tube device
JP5449591B2 (en) Electron emitter and pixel tube of field emission display device using the same
KR102027407B1 (en) Field emitter and cold cathod structure using cnt yarns
CN104616952B (en) Yin controls more cathode distribution X-ray apparatus
JP2002022899A (en) Electron beam irradiator
JP4414114B2 (en) Fluorescent display tube, driving method thereof and driving circuit
KR20170003083A (en) Manufacturing Process For Field Emission X-ray Source Device
KR20160102748A (en) Field Emission X-Ray Source Device
JP2007080704A (en) Field emission type electron gun and its power supply voltage control method
EP3174083A1 (en) Field-emission x-ray source
US20230411106A1 (en) Multi-beam x-ray source and method for forming same
US20190189384A1 (en) Bipolar grid for controlling an electron beam in an x-ray tube

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 19823655

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 19823655

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: JP