WO2013154259A1 - Tube à rayons x de petite taille scellé sous vide faisant appel à un émetteur de faisceau d'électrons à base de nanotubes de carbone - Google Patents

Tube à rayons x de petite taille scellé sous vide faisant appel à un émetteur de faisceau d'électrons à base de nanotubes de carbone Download PDF

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Publication number
WO2013154259A1
WO2013154259A1 PCT/KR2013/000127 KR2013000127W WO2013154259A1 WO 2013154259 A1 WO2013154259 A1 WO 2013154259A1 KR 2013000127 W KR2013000127 W KR 2013000127W WO 2013154259 A1 WO2013154259 A1 WO 2013154259A1
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Prior art keywords
electron beam
ray
carbon nanotube
ray tube
vacuum
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PCT/KR2013/000127
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English (en)
Korean (ko)
Inventor
허성환
조성오
김현진
하준목
Original Assignee
한국과학기술원
(주)파티클라
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Priority claimed from KR1020130001486A external-priority patent/KR101325210B1/ko
Application filed by 한국과학기술원, (주)파티클라 filed Critical 한국과학기술원
Publication of WO2013154259A1 publication Critical patent/WO2013154259A1/fr

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    • 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
    • H01J35/064—Details of the emitter, e.g. material or structure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2201/00—Electrodes common to discharge tubes
    • H01J2201/30—Cold cathodes
    • H01J2201/304—Field emission cathodes
    • H01J2201/30446—Field emission cathodes characterised by the emitter material
    • H01J2201/30453—Carbon types
    • H01J2201/30469—Carbon nanotubes (CNTs)

Definitions

  • the present invention relates to an X-ray tube, and more particularly, to a vacuum sealed small X-ray tube using a carbon nanotube-based electron beam emitter.
  • the X-ray tube is kept in a vacuum to reduce the kinetic energy and deflection caused by collisions with molecules while the electrons fly to the target.
  • the target is made of a thin metal film whose thickness is determined by considering the penetration depth of the electrons and the ability of heat to be absorbed by the target.
  • the X-ray tube is divided into a fixed X-ray tube and a rotating X-ray tube according to the operation of the anode.
  • Rotating X-ray tubes are generally identical to stationary X-ray tubes, except that the anode rotates to dissipate heat generated by the target.
  • the anode becomes stronger as the X-ray generated from the target goes from the center line toward the cathode, and the effective focal spot size becomes larger, whereas the anode becomes weaker as the X-ray intensity becomes smaller toward the anode.
  • the effect (anode heel effect) will occur.
  • the small X-ray tube is a small X-ray generator having a diameter of 10 mm or less. Easy to install in tight spaces and capable of electrical X-ray control, small X-ray tubes can replace radioisotopes for use in X-ray nondestructive testing, portable X-ray spectroscopy, electrical proximity cancer treatment, intraluminal implantation, or medical imaging. have.
  • X-ray tubes using carbon nanotube electron beam sources having various advantages over thermal electron beam sources have been actively developed.
  • X-ray radiators uniformly distribute the uneven X-ray intensity distribution that occurs during imaging by moving the x-ray apparatus, the negative side when measuring thick areas, and the positive side when taking thin sections. It is to provide a vacuum sealed small X-ray tube using a carbon nanotube electron beam emitter can be represented by.
  • Vacuum sealing type small X-ray tube using a carbon nanotube-based electron beam emitter for solving the above problems has a focusing electrode formed in a cylindrical shape, the carbon nanotubes inserted in the center of the focusing electrode
  • An electron beam generator for extracting an electron beam through an electron beam emitter A ceramic tube inserted into one surface of the electron beam generator and surrounding the focusing electrode;
  • a transmission type X-ray target provided in a direction in which the electron beam is drawn out and simultaneously provided with an X-ray transmission window that emits ionizing radiation into the atmosphere by colliding with the electron beam to generate therapeutic and diagnostic radiation;
  • a connecting anode provided between the transmission type X-ray target and the ceramic tube.
  • the X-ray transmission window is characterized in that it has a shape of any one of a cylindrical, conical, conical cylindrical, lampshade.
  • the X-ray transmission window is characterized in that the outer side is formed of any one material of beryllium, aluminum, magnesium, aluminum nitride, aluminum berylnium alloy, silicon oxide, titanium.
  • the X-ray transmission window is characterized in that the inner side is formed of any one material of tungsten, yttrium, molybdenum, tantalum, silver.
  • the electron beam generating unit may protrude in an inner direction of the X-ray tube.
  • the cross-sectional length of the X-ray tube is at least 10mm or less.
  • Vacuum sealing type small X-ray tube using a carbon nanotube-based electron beam emitter for solving the above problems is a carbon nanotube electron beam emitter-based electron beam generator, ceramic tube, connecting anode, X-ray target Is provided, and vacuum sealing the carbon nanotube electron beam emitter and the ceramic tube, the connecting anode, the X-ray target by vacuum brazing, and melt-bonding the carbon nanotube electron beam emitter through a metal nano powder process It is characterized by.
  • Vacuum sealing type small X-ray tube using a carbon nanotube-based electron beam emitter for solving the above problem is a tip shape in which carbon nanotubes and nano metal powder is bonded to one end of the metal tip by melting Field emission electron beam emitters; Connecting anodes spaced apart from one end surface of the electron beam emitter; And a focusing electrode provided between the electron beam emitter and the connection anode and focusing an electron beam formed between the electron beam emitter and the connection anode.
  • the electron beam emitter and the focusing electrode are applied at the same voltage, but a voltage difference of 10 to 150 kV is generated with respect to the connecting anode, and the focusing electrode and the connecting anode are connected with a ceramic insulator. It is characterized by being fastened to.
  • the ceramic insulator has a hollow cylindrical shape in which the electron beam emitter and the focusing electrode are joined to one side opening, and the other opening is bonded to a connecting anode and an X-ray target so that the inside is maintained in a high vacuum and the outside is vacuum sealed to expose the atmosphere. It features.
  • the X-ray target part may be bonded to the connection anode to generate X-rays having a radial distribution through the collision of the electron beam passing through the connection anode.
  • the electron beam emitter is a cylindrical magnetic or nonmagnetic metal tip having a flat polished cross section having a diameter of 0.01 mm to several mm, and the carbon nanotube having an oxidized and purified tube diameter of 1 to 100 mm and a length of 0.5 to 100 ⁇ m.
  • the magnetic or nonmagnetic nano metal powder having a diameter of 1 nm to 1 ⁇ m, which is capable of chemical and physical adhesion with the oxidizer of the carbon nanotubes by heating, is bonded onto the plane of the metal tip.
  • the connecting anode is provided as a counter electrode for charging a high voltage for generating and accelerating an electron beam in the carbon nanotubes attached to the electron beam emitter, each corner of which is curved to prevent high voltage discharge, and is It is characterized in that the hollow cylindrical cylindrical aperture is formed so that the accelerated electron beam can pass.
  • the focusing electrode is installed in which the electron beam emitter is fixed to the center of the hollow cylinder, and the inclination of the inner cylindrical surface surrounding the outer edge of the electron beam emitter and the end of the cylinder is bent, so that the protruding angle toward the electron beam emitter is increased. And the inclination of the outer cylindrical surface of the hollow cylinder and the end surface of the cylinder is also bent, the protrusion angle toward the outside is removed, and the electron beam emitter is installed at the lower end of the hollow cylinder end section, and the electron beam extraction electric field is focused. It collects in a mold characterized by focusing the extracted electron beam.
  • the ceramic insulator is a hollow cylindrical high voltage insulator made of alumina having an outer diameter of 1 to 30 mm, an inner diameter of 0.5 to 25 mm, a length of 5 to 100 mm, and a purity of 90 to 99.99%. To this end, it is characterized in that the manganese / molybdenum mixture 10 to 70 ⁇ m, nickel 0.5 to 5 ⁇ m is deposited on both ends.
  • the X-ray target is a transmission X-ray having a conical shape of beryllium (Be), aluminum (Al), magnesium (Mg), aluminum nitride (AlN), aluminum beryllium alloy (AlBe), silicon oxide (SixOy), and titanium (Ti).
  • the X-ray target layer generating characteristic radiation of 8 to 30 keV or 50 to 70 keV of tungsten (W), yttrium (Y), molybdenum (Mo), tantalum (Ta) and silver (Ag) on the inner surface of the window Characterized in that the deposition.
  • High voltage drive cable provided with a vacuum sealed small X-ray tube according to another embodiment of the present invention for solving the above problems is provided with a vacuum sealed small X-ray tube and a high voltage cable,
  • the high voltage cable is formed so as to be connected to the ceramic insulator outer diameter side of the vacuum sealed small X-ray tube, the non-insertion of the focusing electrode side, the rear of the focusing electrode, and the junction of the high-voltage cable silica resin (dimethyl siloxane, trimethylated) Vacuum curing molding through a high voltage resin such as silica, and a metal ground paste such as silver paste is connected and coated on the outer surface of the molding with the connection anode outer surface to enable smooth high voltage operation in the air.
  • silica resin dimethyl siloxane, trimethylated
  • an outermost polymer molding provided with a coolant to inject coolant such as air and water to cool the heat generated from the X-ray target outside the high voltage resin molding layer and the metal ground paste molding layer.
  • the vacuum sealed small X-ray tube using the carbon nanotube-based electron beam emitter according to the present invention may have a driving tube voltage of 70 kV, an X-ray dose rate, a relatively uniform X-ray space distribution, and a smaller size of the electron beam in the X-ray tube.
  • Miniaturized X-ray tues can be manufactured and used in various industrial and medical diagnosis / treatment in the future.
  • the small X-ray tube according to the present invention can solve the X-ray output limit, X-ray generation reaction rate, power consumption, and miniaturization limit of the existing hot electron beam source by using a carbon nanotube cold field emission electron beam source.
  • FIG. 1 is a schematic diagram of a vacuum sealed small X-ray tube using a carbon nanotube-based electron beam emitter according to an exemplary embodiment of the present invention.
  • FIG. 2 is a detailed view of FIG. 1.
  • FIG. 3 is a photograph actually taken of FIG. 2.
  • FIG. 4 is an X-ray photograph of the small X-ray tube illustrated in FIG. 2.
  • FIG. 5 shows a scanning electron micrograph of an electron beam circle of a vacuum sealed small X-ray tube using a carbon nanotube-based electron beam emitter.
  • Figure 6 (a) is a voltage-current graph of a driving characteristic of a vacuum-sealed small X-ray tube using a carbon nanotube-based electron beam emitter according to an embodiment of the present invention
  • Figure 6 (b) is a small X-ray tube X-ray dose rate and dose rate stability over time.
  • FIG. 7A is a result of measuring an energy spectrum of a small X-ray tube when driving 50 kV
  • FIG. 7B is an X-ray spatial distribution measured at a distance of 1 cm and 3 cm in air.
  • FIG. 8A is an X-ray image of 1.02 times the magnification of a small fish measured using a small X-ray tube and a CMOS image detector
  • FIG. 8B is a distance and X-ray intensity using the European standard EN12543-5. This is a graph of X-ray focal size.
  • FIG 9 is an exemplary view showing a high voltage driving cable for a carbon nanotube-based micro-X-ray tube according to an embodiment of the present invention.
  • Vacuum sealing type small X-ray tube using a carbon nanotube-based electron beam emitter for solving the above problems has a focusing electrode formed in a cylindrical shape, the carbon nanotubes inserted in the center of the focusing electrode
  • An electron beam generator for extracting an electron beam through an electron beam emitter A ceramic tube inserted into one surface of the electron beam generator and surrounding the focusing electrode;
  • a transmission type X-ray target provided in a direction in which the electron beam is drawn out and simultaneously provided with an X-ray transmission window that emits ionizing radiation into the atmosphere by colliding with the electron beam to generate therapeutic and diagnostic radiation;
  • a connecting anode provided between the transmission type X-ray target and the ceramic tube.
  • the X-ray transmission window is characterized in that it has a shape of any one of a cylindrical, conical, conical cylindrical, lampshade.
  • the X-ray transmission window is characterized in that the outer side is formed of any one material of beryllium, aluminum, magnesium, aluminum nitride, aluminum berylnium alloy, silicon oxide, titanium.
  • the X-ray transmission window is characterized in that the inner side is formed of any one material of tungsten, yttrium, molybdenum, tantalum, silver.
  • the electron beam generating unit may protrude in an inner direction of the X-ray tube.
  • the cross-sectional length of the X-ray tube is at least 10mm or less.
  • Vacuum sealing type small X-ray tube using a carbon nanotube-based electron beam emitter for solving the above problems is a carbon nanotube electron beam emitter-based electron beam generator, ceramic tube, connecting anode, X-ray target Is provided, and vacuum sealing the carbon nanotube electron beam emitter and the ceramic tube, the connecting anode, the X-ray target by vacuum brazing, and melt-bonding the carbon nanotube electron beam emitter through a metal nano powder process It is characterized by.
  • Vacuum sealing type small X-ray tube using a carbon nanotube-based electron beam emitter for solving the above problem is a tip shape in which carbon nanotubes and nano metal powder is bonded to one end of the metal tip by melting Field emission electron beam emitters; Connecting anodes spaced apart from one end surface of the electron beam emitter; And a focusing electrode provided between the electron beam emitter and the connection anode and focusing an electron beam formed between the electron beam emitter and the connection anode.
  • the electron beam emitter and the focusing electrode are applied at the same voltage, but a voltage difference of 10 to 150 kV is generated with respect to the connecting anode, and the focusing electrode and the connecting anode are connected with a ceramic insulator. It is characterized by being fastened to.
  • the ceramic insulator has a hollow cylindrical shape in which the electron beam emitter and the focusing electrode are joined to one side opening, and the other opening is bonded to a connecting anode and an X-ray target so that the inside is maintained in a high vacuum and the outside is vacuum sealed to expose the atmosphere. It features.
  • the X-ray target part may be bonded to the connection anode to generate X-rays having a radial distribution through the collision of the electron beam passing through the connection anode.
  • the electron beam emitter is a cylindrical magnetic or nonmagnetic metal tip having a flat polished cross section having a diameter of 0.01 mm to several mm, and the carbon nanotube having an oxidized and purified tube diameter of 1 to 100 mm and a length of 0.5 to 100 ⁇ m.
  • the magnetic or nonmagnetic nano metal powder having a diameter of 1 nm to 1 ⁇ m, which is capable of chemical and physical adhesion with the oxidizer of the carbon nanotubes by heating, is bonded onto the plane of the metal tip.
  • the connecting anode is provided as a counter electrode for charging a high voltage for generating and accelerating an electron beam in the carbon nanotubes attached to the electron beam emitter, each corner of which is curved to prevent high voltage discharge, and is It is characterized in that the hollow cylindrical cylindrical aperture is formed so that the accelerated electron beam can pass.
  • the focusing electrode is installed in which the electron beam emitter is fixed to the center of the hollow cylinder, and the inclination of the inner cylindrical surface surrounding the outer edge of the electron beam emitter and the end of the cylinder is bent, so that the protruding angle toward the electron beam emitter is increased. And the inclination of the outer cylindrical surface of the hollow cylinder and the end surface of the cylinder is also bent, the protrusion angle toward the outside is removed, and the electron beam emitter is installed at the lower end of the hollow cylinder end section, and the electron beam extraction electric field is focused. It collects in a mold characterized by focusing the extracted electron beam.
  • the ceramic insulator is a hollow cylindrical high voltage insulator made of alumina having an outer diameter of 1 to 30 mm, an inner diameter of 0.5 to 25 mm, a length of 5 to 100 mm, and a purity of 90 to 99.99%. To this end, it is characterized in that the manganese / molybdenum mixture 10 to 70 ⁇ m, nickel 0.5 to 5 ⁇ m is deposited on both ends.
  • the X-ray target is a transmission X-ray having a conical shape of beryllium (Be), aluminum (Al), magnesium (Mg), aluminum nitride (AlN), aluminum beryllium alloy (AlBe), silicon oxide (SixOy), and titanium (Ti).
  • the X-ray target layer generating characteristic radiation of 8 to 30 keV or 50 to 70 keV of tungsten (W), yttrium (Y), molybdenum (Mo), tantalum (Ta) and silver (Ag) on the inner surface of the window Characterized in that the deposition.
  • High voltage drive cable provided with a vacuum sealed small X-ray tube according to another embodiment of the present invention for solving the above problems is provided with a vacuum sealed small X-ray tube and a high voltage cable,
  • the high voltage cable is formed so as to be connected to the ceramic insulator outer diameter side of the vacuum sealed small X-ray tube, the non-insertion of the focusing electrode side, the rear of the focusing electrode, and the junction of the high-voltage cable silica resin (dimethyl siloxane, trimethylated) Vacuum curing molding through a high voltage resin such as silica, and a metal ground paste such as silver paste is connected and coated on the outer surface of the molding with the connection anode outer surface to enable smooth high voltage operation in the air.
  • silica resin dimethyl siloxane, trimethylated
  • an outermost polymer molding provided with a coolant to inject coolant such as air and water to cool the heat generated from the X-ray target outside the high voltage resin molding layer and the metal ground paste molding layer.
  • Embodiments according to the concept of the present invention may be variously modified and may have various forms, and specific embodiments will be illustrated in the drawings and described in detail in the present specification or application. However, this is not intended to limit the embodiments in accordance with the concept of the present invention to a particular disclosed form, it should be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention.
  • first and / or second may be used to describe various components, but the components should not be limited by the terms.
  • the terms may be named as a first component second component only for the purpose of distinguishing one component from another component, for example without departing from the scope of rights in accordance with the inventive concept.
  • the two components may also be referred to as first components.
  • FIG. 1 is a schematic view of a vacuum sealed small X-ray tube apparatus using a carbon nanotube-based electron beam emitter according to an embodiment of the present invention
  • FIG. 2 is a detailed view of FIG. 1, and FIG. It is a photograph.
  • the vacuum-sealed small X-ray tube 100 using a carbon nanotube electron beam emitter includes an electron beam generator 200, a ceramic tube 160, an X-ray target 180, and a connecting anode 170. It includes.
  • the electron beam generator 200 includes a focusing electrode 130 formed in a cylindrical shape, and extracts an electron beam through a carbon nanotube electron beam emitter 110 inserted into a center of the focusing electrode 130.
  • the carbon nanotube electron beam emitter 110 is manufactured by coating a carbon nanotube paste in which single-wall carbon nanotubes and silver nanoparticles are mixed.
  • the carbon nanotube electron beam emitter 110 may be manufactured by sintering a flat tungsten wire having a diameter of 0.8 mm at a high temperature. have.
  • the carbon nanotube electron beam emitter 110 further includes a metal tip 111 having a flat wire shape at one end thereof, and the carbon nanotube and the metal nano powder are densely mixed at the tip of the tip 111. By heating the tip 111, a carbon nanotube cold field emission electron beam source may be generated.
  • the emitter tip 111 may be formed by mechanical polishing or chemical etching of a metal wire (Wire) end of 0.01 to several mm in diameter.
  • the material may be one of tungsten (W), iron (Fe), nickel (Ni), titanium (Ti), silver (Ag), and copper (Cu).
  • the emitter tip 111 is a non-magnetic having a diameter of 1 nm to 1 ⁇ m capable of chemically and physically bonding the carbon nanotubes with an oxidizer of the carbon nanotubes by heating carbon nanotubes having a diameter of 1 to 100 nm and a length of 0.5 to 100 ⁇ m. It can be formed through the magnetic or magnetic nano metal powder.
  • the carbon nanotube electron beam emitter 110 is fixedly installed at the center of the hollow cylinder of the focusing electrode 130 and the inner cylindrical surface and the end of the cylinder surrounding the outer surface of the carbon nanotube electron beam emitter 110.
  • the inclination of the cross section is bent and the protruding angle toward the outside is removed, and the carbon nanotube electron beam emitter 110 is installed at the lower end of the hollow cylindrical end section, thereby concentrating the electron beam extraction electric field when the electron beam is drawn out.
  • the shape of the focusing electrode 130 may reach the X-ray target 180 without colliding or losing the electron beam generated by the carbon nanotube electron beam emitter 110 with the ceramic insulator (eg, the ceramic tube 160). It is designed using electron beam optical code.
  • the reason for using such an electron beam optical code is that a small amount of electron beam collision in the ceramic insulator can cause high voltage discharge, and thus the electron beam optical system must pay attention to whether the beam is lost.
  • the position inside the focusing electrode 130 of the carbon nanotube electron beam emitter 110 affects the extracted electron beam current and the electron beam trajectory, the condition is determined through the electron beam calculation code and the electron beam drawing experiment.
  • the focusing electrode 130 includes a nonvolatile vacuum getter film 120, and the vacuum getter film 120 adheres to the focusing electrode 130 to seal residual gas inside the sealed X-ray tube 100. Performs the function of adsorption.
  • the ceramic tube 160 is inserted into one surface of the electron beam generator 200 to surround the focusing electrode 130 and formed of alumina (Al 2 O 3 ) to block high voltage generated therein.
  • alumina Al 2 O 3
  • the ceramic tube 160 may be a hollow cylindrical high voltage insulator made of alumina having an outer diameter of 1 to 30 mm, an inner diameter of 0.5 to 25 mm, a length of 5 to 100 mm, and a purity of 90 to 99.99%. Both ends are designed to deposit 10 to 70 ⁇ m of manganese / molybdenum mixture and 0.5 to 5 ⁇ m of nickel so as to enable vacuum sealing bonding with the ultra-small metal electrode.
  • the X-ray target 180 is provided in a direction in which the electron beam (eg, X-ray) is drawn out.
  • the X-ray target 180 includes an X-ray transmission window 150 and an X-ray target layer 140.
  • the X-ray transmission window 150 emits ionizing radiation into the atmosphere by generating a therapeutic and diagnostic radiation by the electron beam collides, the shape may be formed of any one of a cylindrical, conical, conical cylindrical, lampshade. .
  • the cone is an example, but is not limited thereto.
  • the X-ray target layer 140 is formed as a thin film on the inner surface of the X-ray transmission window 150, and the material is tungsten (W), yttrium (Y), molybdenum (Mo), tantalum (Ta), silver It may be any one of (Ag).
  • the angle between the inclined surfaces may be 5 degrees to 60 degrees, and the thickness of the X-ray target layer 140 may be 0.1 to 10 ⁇ m.
  • the X-ray transmission window 150 is beryllium (Be), aluminum (Al), magnesium (Mg), aluminum nitride (AlN), aluminum beryllium alloy (AlBe), silicon oxide (SixOy), titanium (Ti) It may be an alloy through any one material or a combination of).
  • the X-ray target 180 and the ceramic tube 160 are connected through a connecting anode, and the connecting anode is uniform in a 360 degree solid angle direction by the conical transmissive X-ray transmission window 150 and the X-ray target layer 140.
  • the X-ray generation line 162 may be obtained.
  • the carbon nanotube cold field emission electron beam source 111 provided in the field emission electron beam emitter 110 through the focusing electrode 130 is charged at a high voltage of 0 to -70 kV, and constitutes an X-ray target 180.
  • the X-ray target layer 140 and the X-ray transmission window 150 may be electrically grounded through the connecting anode 170 to simultaneously extract and accelerate the electron beam of the ultra-small X-ray tube 100 in a focused bipolar field emission structure. have.
  • the structure of the X-ray target 180 presented in the present invention is a structure designed to have a uniform spatial distribution of X-rays generated through Monte Carlo computer simulation
  • the X-ray target 180 is a mechanically processed beryllium X-ray transmission window Deposition of the X-ray target layer 140 using a magnetron sputter inside the 140, for example, a tungsten (W) thin film is deposited, the thickness is 1.5 ⁇ m, which is generated under the electron beam conditions of the present X-ray tube 100 It is optimized to maximize X-rays.
  • connection anode 170 may be separately provided with a lead wire (not shown) connected to an external surface to receive a power supply.
  • the bonding sites are tightly vacuum-sealed, and the ceramic tube 160 made of alumina, which is open at both sides, is bonded to the electron beam generator 200 and the connection anode 170.
  • Both electrodes can be fabricated from cobars with a coefficient of thermal expansion similar to that of ceramics made of alumina.
  • connection anode 170 is used as an intermediate structure for bonding the ceramic tube and the X-ray transmission window made of beryllium material having a different thermal expansion coefficient.
  • the nonvolatile vacuum getter film 120 adsorbs the residual gas inside the sealed X-ray tube 160 attached to the focusing electrode 130.
  • the vacuum getter film 120 is activated during the vacuum bonding process.
  • the outside of the bonded ceramic tube 160 is coated with a silicone resin for improving high voltage insulation to enable X-ray generation experiments in the air.
  • the X-ray tube 100 was safely driven at 70 kV, and no serious high voltage discharge occurred in or out of the ceramic tube 160 during driving.
  • the ultra-small X-ray tube 10 includes a focusing electrode 121 and a high voltage insulating ceramic 150 including a carbon nanotube cold field emission electron beam source 111 and an emitter tip 112.
  • the connecting anode 131 and the conical transmissive X-ray window 132 are sequentially joined.
  • the bonding may be a metal braze is placed between the respective parts to be fixed with a jig and then melt bonded together in a vacuum high temperature furnace.
  • the ultra-small X-ray tube 100 is made of a metal having good workability and bonding property with a metal solder material for high voltage charging and bonding.
  • Both opening cross-sections of the ceramic tube 10 are melt diffusion coated with a thin layer of manganese, molybdenum and nickel to provide a high seal without vacuum outflow during metal solder bonding.
  • a thin X-ray target layer 133 is provided according to the inner surface shape of the transmissive X-ray window 132 to generate X-rays having a uniform distribution according to the processed shape during the electron beam collision.
  • Low atomic weight beryllium, aluminum and titanium based lightest metals and semiconductor / insulator materials such as aluminum nitride, beryllium oxide and silicon oxide are used for the transmission of X-rays.
  • FIG. 5 is a scanning electron micrograph of a carbon nanotube cold field emission electron beam source manufactured according to an embodiment of the present invention.
  • the field emission type electron beam emitter tip 111 is a metal tip having a flat wire shape, and the carbon nanotube and the metal nano powder are densely installed at the tip of the tip, and then heated to form a cold carbon nanotube cold field system. It constitutes an emission electron beam source.
  • the emitter tip 111 mechanically polishes or chemically etches a metal wire end of diameter 0.01 to number to form a flat end surface.
  • Tungsten (W), iron (Fe), nickel (Ni), titanium (Ti), silver (Ag), copper (Cu) and the like can be used as the metal material.
  • FIG. 6 (a) is a voltage-current graph of driving characteristics of a vacuum-sealed bipolar tube-shaped small X-ray tube manufactured according to an embodiment of the present invention
  • FIG. 6 (b) shows X-ray dose rate and time of the small X-ray tube. This is a graph measuring the dose rate stability.
  • the current I denotes an electron beam current reaching the X-ray target
  • the voltage V denotes a tube voltage charged between the electron beam generator and the X-ray target.
  • the electron beam current gathered from the X-ray target and the current generated from the carbon nanotube electron beam emitter were measured and compared.
  • the electron beam generator is charged with a negative voltage to drive the X-ray tube, and the anode and the X-ray target are electrically grounded.
  • the driving voltage for drawing the 10 mA / cm 2 electron beam of the X-ray tube was 29 kV, and when the tube voltage was increased to 70 kV, the current of the X-ray target part was found to be 617 ⁇ A (0.123 A / cm 2 ). In addition, it was confirmed that the electron beam current was changed to about 2% in 50 kV driving.
  • the X-ray tube was 60 kV or higher, and at tube voltage, the driving could not be realized for a long time continuously due to the X-ray target overheating.
  • the driving start voltage and the generated current may vary according to the position of the carbon nanotube electron beam emitter 110 inserted into the focusing cathode 130.
  • the carbon nanotube electron beam emitter 110 is installed at the bottom of 0.5mm of the focusing cathode 130 to investigate the driving start voltage according to the carbon nanotube electron beam emitter installation position before vacuum bonding.
  • the driving start voltage for generating 10 mA / cm 2 at the positions of 0 mm, 0.3 mm, 0.5 mm, and 0.7 mm was changed to 8 kV, 19 kV, 29 kV, and 40 kV.
  • the X-ray tube 100 of the present invention is a bipolar tubular, it is impossible to change the current at a fixed tube voltage like a tripolar tubular. However, adjusting the position of the focusing cathode and the carbon nanotube electron beam emitter in advance of manufacturing can compensate for this disadvantage.
  • the X-ray dose rate is measured using an ion chamber at a distance of 1 cm in air from the X-ray tube, and 108.1Gy ⁇ cm 2 min ⁇ 1 when driving 50 kV and 252 ⁇ A.
  • X-rays which are 15 times higher than 10 Ci HDR 192Ir isotope sources.
  • the X-ray dose rate shows a change rate of ⁇ 2.7%, and performance is maintained even when used continuously for 1 hour a day for 2 months under the same conditions.
  • the developed small X-ray tube has high X-ray dose rate, short term and long term stability.
  • FIG. 7A is a result of measuring an energy spectrum of a small X-ray tube when driving 50 kV
  • FIG. 7B is an X-ray spatial distribution measured at a distance of 1 cm and 3 cm in air.
  • the spectra described in the drawing include braking radiation X-rays of 50 keV or less and characteristic radiation emitted from tungsten.
  • X-rays were measured as 108.1 Gy ⁇ min ⁇ 1 at 0 degrees, 102.8 Gy ⁇ min ⁇ 1 at ⁇ 60 ° C., and 86.1 Gy ⁇ min ⁇ 1 at ⁇ 120 ° C., and the dose difference was almost uniform at 20% in the 240 ° spatial sense range. It can be seen that an X-ray is generated.
  • Such X-ray tubes can be used for brachytherapy or intraluminal X-ray diagnosis.
  • FIG. 8A is an X-ray image of 1.02 times the magnification of a small fish measured using a small X-ray tube and a CMOS image detector
  • FIG. 8B is a distance and X-ray intensity using the European standard EN12543-5. This is a graph of X-ray focal size.
  • the X-ray focal size was analyzed using the European standard EN12543-5. After obtaining a cruciform copper plate (0.1mm thickness) image with a magnification of 1.25 times, the X-ray focal size of the small X-ray tube was measured to be about 3.7 mm by analyzing anti-shadow images on the horizontal and vertical axes. This may make the inside / outside diameter of the small X-ray tube smaller than the present, it is possible to manufacture a smaller X-ray tube.
  • FIG 9 is an exemplary view showing a high voltage driving cable for a carbon nanotube-based micro-X-ray tube according to an embodiment of the present invention.
  • the carbon nanotube-based ultra-small voltage X-ray tube 500 of the high voltage driving cable 500 includes a high voltage cable inserting part 31, a high voltage resin molding part 21, a metal ground molding part 22, and a coolant.
  • the flow path 25 and the high voltage cable inlet 32 is included.
  • the high voltage driving cable 10 has a hollow formed therein, the high voltage cable inserting portion 31 is formed at one end of the high voltage cable 500, and the high voltage cable inlet 32 is formed at the other end thereof.
  • the high voltage cable inserting portion 31 is inserted into the small X-ray tube 100 according to an embodiment of the present invention.
  • the inserted ultra-small X-ray tube 100 is inserted into the high voltage cable so that the ceramic tube protrudes to the outside through the high voltage cable inserting portion 31.
  • the high voltage resin molding 21 is formed in a tubular shape to surround the micro X-ray tube 100 and the high voltage cable inserting portion 31, and insulates the high voltage generated from the micro X-ray tube 100 from the external atmosphere. Do this.
  • the metal ground molding 22 is formed in a tubular shape surrounding the high voltage resin molding 21 and is connected to a connection anode of the micro X-ray tube 100 to perform a function of connecting ground to the connection anode.
  • the junction of the high-voltage cable connected to the outer diameter side of the ceramic insulator, the non-insertion of the focusing electrode, and the back of the focusing electrode exposed to the outside may be formed through a high voltage resin such as silica resin (dimethyl siloxane, trimethylated silica, etc.). Vacuum curing molding.
  • the outer surface of the metal ground molding 22 may be coated with a metal ground paste such as silver paste on the outer surface of the connection anode to enable smooth high voltage driving even in the air.
  • the coolant flow path 25 is formed in a tubular shape surrounding the metal ground molding 22 and performs a function of removing heat generated from the small X-ray tube 100.
  • An inlet (not shown) of a coolant flow path through which coolant flows is formed at one central side of the high voltage cable 500, and an outlet 24 of the coolant flow path is formed at the opposite side.
  • the high voltage cable inlet 32 performs a power supply function for applying a high voltage to the micro X-ray tube 100.
  • a cooling passage 25 may further be provided between the high voltage resin molding layer and the metal ground paste molding layer to inject a coolant such as air or water to cool the heat generated from the small sealing X-ray tube.
  • a coolant such as air or water to cool the heat generated from the small sealing X-ray tube.
  • the surface of the flow path 25 is treated through polymer molding fixing.
  • the present invention provides a vacuum sealed small X-ray tube using a carbon nanotube electron beam has a drive tube voltage of 70 kV, a high X-ray dose rate, and a relatively uniform X-ray spatial distribution. Due to the small size of the electron beam in the X-ray tube, it is possible to manufacture a smaller X-ray tube and be used for various industrial and medical diagnosis / treatment in the future.
  • Vacuum sealed small X-ray tube using a carbon nanotube electron beam emitter according to the present invention can be modified and applied in various forms within the scope of the technical idea of the present invention and is not limited to the above embodiments.
  • the embodiments and drawings are merely for the purpose of describing the contents of the invention in detail, and are not intended to limit the scope of the technical idea of the invention, the present invention described above is common knowledge in the technical field to which the present invention belongs As those skilled in the art may have various substitutions, modifications, and changes without departing from the technical spirit of the present invention, it is not limited to the embodiments and the accompanying drawings. Judgment should be made including scope and equivalence.
  • 100 small sealing tube 110: carbon nanotube electron beam emitter
  • emitter tip 120 vacuum getter film
  • X-ray transmission window 160 ceramic tube

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  • X-Ray Techniques (AREA)

Abstract

La présente invention concerne un tube à rayons X de petite taille scellé sous vide faisant appel à un émetteur de faisceau d'électrons à base de nanotubes de carbone, lequel tube à rayons X comprend : une unité de génération de faisceau d'électrons comportant une électrode de focalisation cylindrique et prolongeant un faisceau d'électrons à travers un émetteur à effet de champ inséré dans le centre de l'électrode de focalisation ; un tube en céramique inséré à un côté de l'unité de génération de faisceau d'électrons pour enserrer l'électrode de focalisation ; une cible de rayons X de transmission agencée dans la direction de prolongement du faisceau d'électrons et constituée par une fenêtre de transmission de rayons X contre laquelle le faisceau d'électrons entre en collision de façon à générer des faisceaux de radiothérapie et qui émet un rayonnement ionisant vers l'atmosphère ; et une anode de connexion intercalée entre la cible de rayons X de transmission et le tube en céramique.
PCT/KR2013/000127 2012-04-13 2013-01-08 Tube à rayons x de petite taille scellé sous vide faisant appel à un émetteur de faisceau d'électrons à base de nanotubes de carbone WO2013154259A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
KR20120038647 2012-04-13
KR10-2012-0038647 2012-04-13
KR10-2013-0001486 2013-01-07
KR1020130001486A KR101325210B1 (ko) 2012-04-13 2013-01-07 탄소나노튜브 기반의 전자빔 에미터를 이용한 진공밀봉형 소형 엑스선 튜브

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WO2013154259A1 true WO2013154259A1 (fr) 2013-10-17

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109524284A (zh) * 2018-11-28 2019-03-26 深圳先进技术研究院 一种放射治疗x射线源及x射线源装置
CN112349568A (zh) * 2019-08-06 2021-02-09 莫克斯泰克公司 x射线管绝缘、窗以及聚焦板

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Publication number Priority date Publication date Assignee Title
JPH09180660A (ja) * 1995-12-25 1997-07-11 Hamamatsu Photonics Kk 透過型ｘ線管
KR20090011147A (ko) * 2007-07-25 2009-02-02 한국전기연구원 탄소나노튜브 기반 근접 치료 장치
KR20100113675A (ko) * 2009-04-14 2010-10-22 한국과학기술원 탄소나노튜브 전계방출원을 이용한 초소형 엑스선관
KR20110090357A (ko) * 2010-02-03 2011-08-10 한국과학기술원 나노물질 전계방출원을 이용한 초소형 엑스선관

Patent Citations (4)

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Publication number Priority date Publication date Assignee Title
JPH09180660A (ja) * 1995-12-25 1997-07-11 Hamamatsu Photonics Kk 透過型ｘ線管
KR20090011147A (ko) * 2007-07-25 2009-02-02 한국전기연구원 탄소나노튜브 기반 근접 치료 장치
KR20100113675A (ko) * 2009-04-14 2010-10-22 한국과학기술원 탄소나노튜브 전계방출원을 이용한 초소형 엑스선관
KR20110090357A (ko) * 2010-02-03 2011-08-10 한국과학기술원 나노물질 전계방출원을 이용한 초소형 엑스선관

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109524284A (zh) * 2018-11-28 2019-03-26 深圳先进技术研究院 一种放射治疗x射线源及x射线源装置
CN112349568A (zh) * 2019-08-06 2021-02-09 莫克斯泰克公司 x射线管绝缘、窗以及聚焦板

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