CN109411314B - Electron gun with controllable electron energy - Google Patents
Electron gun with controllable electron energy Download PDFInfo
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- CN109411314B CN109411314B CN201811502099.XA CN201811502099A CN109411314B CN 109411314 B CN109411314 B CN 109411314B CN 201811502099 A CN201811502099 A CN 201811502099A CN 109411314 B CN109411314 B CN 109411314B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
- H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
- H01J29/48—Electron guns
- H01J29/481—Electron guns using field-emission, photo-emission, or secondary-emission electron source
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
- H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
- H01J29/48—Electron guns
- H01J29/485—Construction of the gun or of parts thereof
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
- H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
- H01J29/52—Arrangements for controlling intensity of ray or beam, e.g. for modulation
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
- H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
- H01J29/54—Arrangements for centring ray or beam
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
- H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
- H01J29/58—Arrangements for focusing or reflecting ray or beam
- H01J29/62—Electrostatic lenses
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
- H01J29/86—Vessels; Containers; Vacuum locks
- H01J29/861—Vessels or containers characterised by the form or the structure thereof
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
- H01J29/86—Vessels; Containers; Vacuum locks
- H01J29/863—Vessels or containers characterised by the material thereof
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2229/00—Details of cathode ray tubes or electron beam tubes
- H01J2229/48—Electron guns
- H01J2229/4803—Electrodes
- H01J2229/481—Focusing electrodes
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Abstract
The application discloses controllable electron gun of electron energy, electron gun includes: the electron beam generating device comprises an insulating support, an emitting electrode, a control electrode and a focusing electrode, wherein the emitting electrode is used for emitting an electron beam, the control electrode is used for controlling the electron energy of the electron beam, and the focusing electrode is used for controlling the beam diameter of the electron beam. The insulating support comprises a ceramic circular plate and an epoxy support column, the top end of the epoxy support column is fixed at the edge of the ceramic circular plate, the emitter is installed on the ceramic circular plate, the control electrode and the focusing electrode are respectively fixed on the epoxy support column, the control electrode is located below the emitter, the focusing electrode is located below the control electrode, and a tested sample is located below the focusing electrode. The control electrode and the focusing electrode are externally connected with a high-voltage power supply, and the high-voltage power supply is used for applying negative high voltage to the control electrode and applying positive high voltage to the focusing electrode, so that the control electrode and the focusing electrode can respectively control the electron energy and the beam diameter of the electron beam.
Description
Technical Field
The application relates to the technical field of vacuum electronic devices, in particular to an electron gun with controllable electron energy.
Background
As an electrical insulating material, a dielectric material is widely used in the fields of national defense, detection, and communication, for example, in power cables or in spacecraft. The dielectric material is easy to generate breakdown or electrostatic discharge in the using process, and once the phenomenon occurs, the operation failure of the equipment can be caused. In general, in order to reduce the probability of occurrence of breakdown or electrostatic discharge, it is necessary to study the charge transport properties of dielectric materials.
In studying the charge transport properties of dielectric materials, it is generally necessary to inject electrons into the interior of the dielectric material and then to conduct a property test experiment. Therefore, when studying the charge transport properties of the dielectric material, the injection of electrons is important, and the electron energy and current density of the injected electrons affect the accuracy of the property test. In the prior art, electron guns are generally used to achieve the injection of electrons. The electron gun is a device for generating electron beams, and by applying current, the electron gun emits electron beams with certain speed, and the electron beams hit in the dielectric material, so that the next charge characteristic test can be performed.
However, in the research process of the present invention, the applicant found that in the electron gun of the prior art, the electron beam is emitted from the cathode, and the electron energy cannot be effectively and precisely controlled, and the electron energy of the emitted electron beam has uncertainty, that is, the electron gun of the prior art emits electron beam energy which is not precise enough, thereby reducing the accuracy of the charge characteristic test of the dielectric material.
Disclosure of Invention
In order to solve the problem that the accuracy of a charge characteristic test of a dielectric material is reduced due to the fact that the electron energy of an electron beam cannot be effectively and accurately regulated and controlled in an electron gun in the prior art, the application discloses an electron gun with controllable electron energy through the following embodiments.
The application discloses controllable electron gun of electron energy, electron gun includes: the electron beam generating device comprises an insulating support 1, an emitter 2, a control electrode 3 and a focusing electrode 4, wherein the emitter 2 is used for emitting an electron beam, the control electrode 3 is used for controlling the electron energy of the electron beam, and the focusing electrode 4 is used for controlling the beam diameter of the electron beam;
the insulating bracket 1 comprises a ceramic circular plate 11 and an epoxy strut 12, the top end of the epoxy strut 12 is fixed at the edge of the ceramic circular plate 11, the emitter 2 is mounted on the ceramic circular plate 11, the control electrode 3 and the focusing electrode 4 are respectively fixed on the epoxy strut 12, the control electrode 3 is positioned below the emitter 2, the focusing electrode 4 is positioned below the control electrode 3, and a sample to be tested is positioned below the focusing electrode 4;
the control electrode 3 with the external high voltage power supply of focus pole 4, high voltage power supply be used for to negative high voltage is applyed to the control electrode 3, makes control electrode 3 with be located form the electric field between the earthing pole of being tested the appearance below, the electric field is used for controlling electron beam electron energy's size, high voltage power supply still be used for to focus pole 4 applys positive high voltage, focus the pole passes through positive high voltage control the beam diameter of electron beam.
Optionally, the emitter 2 includes a metal block 20, a metal sleeve 21, a ceramic sleeve 22, a copper bolt 23, a tungsten wire base 24, and a tungsten wire 25;
the metal sleeve 21 and the metal block 20 are used for mounting the emitter 2 on the ceramic circular plate 11, the ceramic sleeve 22 is located inside the metal sleeve 21, the ceramic sleeve 22 is used for realizing electrical isolation, one end of the copper bolt 23 is located inside the ceramic sleeve 22, the other end of the copper bolt 23 extends out of the metal sleeve 21 and the ceramic sleeve 22 and is fixed with the upper part of the tungsten filament base 24, the tungsten filament 25 is fixed on the lower part of the tungsten filament base 24, and the electron beam is emitted from the tungsten filament 25.
Optionally, the metal block 20 is a stainless steel metal square, and the metal sleeve 21 is a stainless steel metal sleeve.
Optionally, two circular holes are formed in the plate surface of the ceramic circular plate 11, the two circular holes are symmetrical with respect to the circle center of the ceramic circular plate 11, two first threaded holes are formed in the metal block 20, two metal sleeves 21 are provided, first threads are provided at the top end of each metal sleeve 21, and after the top end of each metal sleeve 21 is connected with the metal block 20 through the first threaded holes and the first threads, the metal sleeve passes through the two circular holes and is mounted on the ceramic circular plate 11;
the metal sleeve 21 is of a hollow structure, the outer diameter of the bottom of the metal sleeve 21 is equal to the outer diameter of the upper part of the metal sleeve, the inner diameter of the bottom of the metal sleeve 21 is smaller than the inner diameter of the upper part of the metal sleeve, and the bottom of the metal sleeve 21 is used for clamping the ceramic sleeve 22;
the ceramic sleeve 22 is of a hollow structure, the outer diameter of the bottom of the ceramic sleeve 22 is smaller than the outer diameter of the upper part of the ceramic sleeve, the outer diameter of the upper part of the ceramic sleeve 22 is smaller than the inner diameter of the upper part of the metal sleeve 21, the outer diameter of the upper part of the ceramic sleeve 22 is larger than the inner diameter of the bottom of the metal sleeve 21, the ceramic sleeve 22 penetrates into the metal sleeve and is clamped at the bottom end of the metal sleeve 21, and the inner diameter of the bottom of the ceramic sleeve 22 is smaller than the inner diameter of the upper part of the ceramic;
the copper bolt 23 is of a hollow structure, the copper bolt 23 comprises an upper hollow cylinder and a lower hollow cylinder, the inner diameters of the upper hollow cylinder and the lower hollow cylinder are equal, the outer diameter of the upper hollow cylinder is larger than that of the lower hollow cylinder, the outer diameter of the upper hollow cylinder is smaller than that of the upper part of the ceramic sleeve 22, the outer diameter of the upper hollow cylinder is larger than that of the bottom of the ceramic sleeve 22, and the copper bolt 23 penetrates into the ceramic sleeve 22 and is clamped at the bottom of the ceramic sleeve 22 through the upper hollow cylinder;
a second threaded hole is formed in the upper portion of the tungsten wire base 24, second threads are formed in the bottom of a lower hollow cylinder of the copper bolt 23, and the bottom of the copper bolt 23 is fixed to the upper portion of the tungsten wire base 24 through the second threaded hole and the second threads.
Optionally, the tungsten filament 25 is spiral in the horizontal plane, two ends of the spiral tungsten filament 25 extend out of a section of tungsten filament for fixing on the vertical plane, and the tungsten filament 25 is fixed on the lower part of the tungsten filament base 24 through a pressing block 240;
the lower part of the tungsten filament base 24 and the pressing block 240 are respectively provided with a third threaded hole, the lower part of the tungsten filament base 24 and the pressing block 240 are fixed together in a bolt perforation manner, and the tungsten filament 25 is fixed between the lower part of the tungsten filament base 24 and the pressing block 240.
Optionally, a wire slot is formed in the surface of the pressing block 240, the wire slot is vertically downward, and the wire slot is used for placing the tungsten filament 25 and fixing the tungsten filament 25 between the pressing block 240 and the lower portion of the tungsten filament base 24.
Optionally, the emitter 2 is provided with a conducting wire 26, the conducting wire 26 is used for being externally connected with a direct current voltage stabilizing source, and the direct current voltage stabilizing source is used for controlling the current density of the electron beam.
Optionally, the lead 26 is inserted into the metal sleeve 21 and the ceramic sleeve 22 and fixed inside the copper bolt 23;
a fourth threaded hole is formed in the lower hollow cylinder of the copper bolt 23, and the lead 26 is fixed inside the lower hollow cylinder of the copper bolt 23 through a bolt 27 and the fourth threaded hole.
Optionally, a first circular ring is arranged on the upper portion of the control electrode 3, two first fixing holes are formed in the first circular ring, the two first fixing holes are symmetrical with respect to the center of the first circular ring, and the first fixing holes are used for penetrating through the epoxy support post 12 and fixing the control electrode 3 on the epoxy support post 12 through epoxy nuts;
the lower part of the control electrode 3 is a thin-wall cylinder, and the diameter of the thin-wall cylinder is equal to the inner diameter of the first circular ring;
the spiral plane of the tungsten filament 25 extends into the thin-walled cylinder, and the electron beam emitted by the tungsten filament 25 is controlled through the thin-walled cylinder.
Optionally, the upper part of the focusing electrode 4 is of a horn-type opening structure, and the inner diameter of the focusing electrode gradually increases from top to bottom;
the lower part of the focusing electrode 4 is a second circular ring, the inner diameter of the second circular ring is equal to the maximum inner diameter of the upper part of the focusing electrode 4, the second circular ring is provided with two second fixing holes, the two second fixing holes are symmetrical about the circle center of the second circular ring, and the second fixing holes are used for penetrating through the epoxy support column 12 and fixing the focusing electrode 4 on the epoxy support column 12 through epoxy nuts.
The application discloses controllable electron gun of electron energy, electron gun includes: the electron beam generating device comprises an insulating support, an emitting electrode, a control electrode and a focusing electrode, wherein the emitting electrode is used for emitting an electron beam, the control electrode is used for controlling the electron energy of the electron beam, and the focusing electrode is used for controlling the beam diameter of the electron beam. The insulating support comprises a ceramic circular plate and an epoxy support column, the top end of the epoxy support column is fixed at the edge of the ceramic circular plate, the emitter is installed on the ceramic circular plate, the control electrode and the focusing electrode are respectively fixed on the epoxy support column, the control electrode is located below the emitter, the focusing electrode is located below the control electrode, and a tested sample is located below the focusing electrode. The control electrode and the focusing electrode are externally connected with a high-voltage power supply, and the high-voltage power supply is used for applying negative high voltage to the control electrode and applying positive high voltage to the focusing electrode, so that the control electrode and the focusing electrode can respectively control the electron energy and the beam diameter of the electron beam.
The application discloses controllable electron gun of electron energy applys negative high pressure to the control electrode through setting up high voltage power supply for form the electric field between control electrode and the earthing pole that is located the sample tested below, after the electron beam sent from the projecting pole, under the effect of electric field force, the electron beam has obtained restraint and acceleration, and the field intensity between control electrode and the earthing pole is big more, and the electron energy of the electron beam that so acquires is also big more. When the electron beam passes through the focusing electrode, the electron beam is subjected to the action of field intensity again due to the positive pressure applied on the focusing electrode, and the beam diameter is further restricted through the horn-shaped opening of the focusing electrode. Therefore, the electron gun disclosed by the application can further control the voltage applied to the control electrode and the focusing electrode by controlling the size of the external high-voltage power supply, finally can accurately control the electron energy size and the beam diameter size of the electron beam, and effectively improves the accuracy of a tested sample, namely a charge characteristic test of the dielectric material.
Drawings
In order to more clearly explain the technical solution of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious to those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic structural diagram of an electron gun with controllable electron energy according to an embodiment of the present disclosure;
FIG. 2 is a front view of an electron gun with controllable electron energy according to an embodiment of the present disclosure;
fig. 3 is a schematic structural diagram of a metal block and a metal sleeve in an electron gun with controllable electron energy according to an embodiment of the present disclosure;
fig. 4 is a schematic structural diagram of a ceramic sleeve in an electron gun with controllable electron energy according to an embodiment of the present application;
FIG. 5 is a schematic structural diagram of a copper plug in an electron gun with controllable electron energy according to an embodiment of the present disclosure;
fig. 6 is a schematic structural diagram of a tungsten filament in an electron gun with controllable electron energy according to an embodiment of the present application.
Detailed Description
In order to solve the problem that the accuracy of a charge characteristic test of a dielectric material is reduced due to the fact that the electron energy of an electron beam cannot be effectively and accurately regulated and controlled in an electron gun in the prior art, the application discloses an electron gun with controllable electron energy through the following embodiments.
An electron gun with controllable electron energy disclosed in the present application, referring to fig. 1, includes: the electron beam generating device comprises an insulating support 1, an emitter 2, a control electrode 3 and a focusing electrode 4, wherein the emitter 2 is used for emitting an electron beam, the control electrode 3 is used for controlling the electron energy of the electron beam, and the focusing electrode 4 is used for controlling the beam diameter of the electron beam.
Wherein insulating support 1 is mainly used for fixed projecting pole 2, control pole 3 and focus pole 4 to through the mounted position of reasonable setting between projecting pole 2, control pole 3 and the focus pole 4, can effectively improve insulating, adiabatic and prevent the effect of puncturing.
Referring to fig. 2, the insulating support 1 includes a ceramic circular plate 11 and an epoxy pillar 12, the top end of the epoxy pillar 12 is fixed at the edge of the ceramic circular plate 11, the emitter 2 is mounted on the ceramic circular plate 11, the control electrode 3 and the focusing electrode 4 are respectively fixed on the epoxy pillar 12, the control electrode 3 is located below the emitter 2, the focusing electrode 4 is located below the control electrode 3, and the sample to be tested is located below the focusing electrode 4.
The ceramic round plate 11 and the epoxy pillar 12 in the insulating bracket 1 have an insulating function while playing a supporting function, wherein the epoxy pillar 12 has the advantages of light weight and easy processing. The test sample refers to a dielectric material subjected to a charge characteristic test.
The control electrode 3 with the external high voltage power supply of focus pole 4, high voltage power supply be used for to negative high voltage is applyed to the control electrode 3, makes control electrode 3 with be located form the electric field between the earthing pole of being tested the appearance below, the electric field is used for controlling electron beam electron energy's size, high voltage power supply still be used for to focus pole 4 applys positive high voltage, focus the pole passes through positive high voltage control the beam diameter of electron beam.
The grounding electrode is arranged below the sample to be tested, and in specific operation, the grounding electrode can be realized by grounding one metal block. By applying negative high voltage on the control electrode 3, a certain electric field is formed between the control electrode 3 and the grounding electrode, electrons with negative polarity are in a free state when being just emitted from the emitter 2, and move towards the grounding electrode in an accelerating way under the action of the electric field to form electron beams. The stronger the electric field, i.e. the greater the absolute value of the negative high voltage applied to the gate 3, the greater the energy of the electron beam formed. In the process of downward emission of the electron beam, the electron beam passes through the focusing electrode, and due to the fact that positive high voltage is applied to the focusing electrode, the electron beam with negative polarity is attracted, and the beam diameter of the electron beam is controlled after the electron beam passes through the focusing electrode. By controlling the beam diameter of the electron beam, the more concentrated the energy of the electron beam, the more precise the position on the sample to be tested is finally hit.
The application discloses controllable electron gun of electron energy, electron gun includes: the electron beam generating device comprises an insulating support, an emitting electrode, a control electrode and a focusing electrode, wherein the emitting electrode is used for emitting an electron beam, the control electrode is used for controlling the electron energy of the electron beam, and the focusing electrode is used for controlling the beam diameter of the electron beam. The insulating support comprises a ceramic circular plate and an epoxy support column, the top end of the epoxy support column is fixed at the edge of the ceramic circular plate, the emitter is installed on the ceramic circular plate, the control electrode and the focusing electrode are respectively fixed on the epoxy support column, the control electrode is located below the emitter, the focusing electrode is located below the control electrode, and a tested sample is located below the focusing electrode. The control electrode and the focusing electrode are externally connected with a high-voltage power supply, and the high-voltage power supply is used for applying negative high voltage to the control electrode and applying positive high voltage to the focusing electrode, so that the control electrode and the focusing electrode can respectively control the electron energy and the beam diameter of the electron beam.
The application discloses controllable electron gun of electron energy applys negative high pressure to the control electrode through setting up high voltage power supply for form the electric field between control electrode and the earthing pole that is located the sample tested below, after the electron beam sent from the projecting pole, under the effect of electric field force, the electron beam has obtained restraint and acceleration, and the field intensity between control electrode and the earthing pole is big more, and the electron energy of the electron beam that so acquires is also big more. When the electron beam passes through the focusing electrode, the electron beam is subjected to the action of field intensity again due to the positive pressure applied on the focusing electrode, and the beam diameter is further restricted through the horn-shaped opening of the focusing electrode. Therefore, the electron gun disclosed by the application can further control the voltage applied to the control electrode and the focusing electrode by controlling the size of the external high-voltage power supply, finally can accurately control the electron energy size and the beam diameter size of the electron beam, and effectively improves the accuracy of a tested sample, namely a charge characteristic test of the dielectric material.
Further, the emitter 2 includes a metal block 20, a metal sleeve 21, a ceramic sleeve 22, a copper bolt 23, a tungsten wire base 24, and a tungsten wire 25.
The metal sleeve 21 and the metal block 20 are used for mounting the emitter 2 on the ceramic circular plate 11, the ceramic sleeve 22 is located inside the metal sleeve 21, the ceramic sleeve 22 is used for realizing electrical isolation, one end of the copper bolt 23 is located inside the ceramic sleeve 22, the other end of the copper bolt 23 extends out of the metal sleeve 21 and the ceramic sleeve 22 and is fixed with the upper part of the tungsten filament base 24, the tungsten filament 25 is fixed on the lower part of the tungsten filament base 24, and the electron beam is emitted from the tungsten filament 25.
Tungsten filaments have high melting points and high corrosion resistance, and therefore tungsten filaments are generally used as materials for emitting electrons in electron guns.
The whole of the emitter 2 is suspended by gravity from the ceramic disk 11 by means of the metal block 20, wherein the ceramic sleeve 22 is placed by gravity inside the metal sleeve 21, and likewise, one end of the copper pin 23 is suspended by gravity inside the ceramic sleeve 22.
Further, the metal block 20 is a stainless steel metal square block, and the metal sleeve 21 is a stainless steel metal sleeve.
Furthermore, two round holes are formed in the plate surface of the ceramic circular plate 11, the two round holes are symmetrical with respect to the circle center of the ceramic circular plate 11, two first threaded holes are formed in the metal block 20, two metal sleeves 21 are provided, first threads are arranged at the top ends of the metal sleeves 21, and the top ends of the metal sleeves 21 penetrate through the two round holes and are installed on the ceramic circular plate 11 after being connected with the metal block 20 through the first threaded holes and the first threads.
Referring to fig. 3, fig. 3 is a schematic structural view illustrating that the metal block 20 and the metal sleeve 21 are installed together, the metal sleeve 21 is a hollow structure, the outer diameter of the bottom of the metal sleeve 21 is equal to the outer diameter of the upper portion, the inner diameter of the bottom of the metal sleeve 21 is smaller than the inner diameter of the upper portion, and the bottom of the metal sleeve 21 is used for clamping the ceramic sleeve 22.
Specifically, as an example, in the embodiment of the present application, the inner diameter of the metal sleeve 21 at a distance of 3mm from the lower nozzle is changed from 12mm to 9 mm.
Referring to fig. 4, the ceramic sleeve 22 is a hollow structure, the outer diameter of the bottom of the ceramic sleeve 22 is smaller than the outer diameter of the upper part, the outer diameter of the upper part of the ceramic sleeve 22 is smaller than the inner diameter of the upper part of the metal sleeve 21, the outer diameter of the upper part of the ceramic sleeve 22 is larger than the inner diameter of the bottom of the metal sleeve 21, the ceramic sleeve 22 penetrates into the metal sleeve and is clamped at the bottom end of the metal sleeve 21, and the inner diameter of the bottom of the ceramic sleeve 22 is smaller than the inner diameter of the upper part for clamping the copper plug 23.
The ceramic sleeve 22 is disposed between the metal sleeve 21 and the copper plug 23, and is used for realizing insulation between the metal sleeve 21 and the copper plug 23 and between the metal sleeve 21 and the conductive wire, so as to effectively prevent metal discharge breakdown. Compared with the ceramic plate commonly used in the prior art to realize the insulation function, the ceramic bushing 22 in the present application has the advantages of small volume, light weight and high temperature resistance, and can achieve the purposes of heat insulation and insulation while saving space.
Referring to fig. 5, the copper bolt 23 is a hollow structure, the copper bolt 23 includes an upper hollow cylinder and a lower hollow cylinder, the inner diameters of the upper hollow cylinder and the lower hollow cylinder are equal, the outer diameter of the upper hollow cylinder is larger than the outer diameter of the lower hollow cylinder, the outer diameter of the upper hollow cylinder is smaller than the inner diameter of the upper portion of the ceramic sleeve 22, the outer diameter of the upper hollow cylinder is larger than the inner diameter of the bottom of the ceramic sleeve 22, and the copper bolt 23 penetrates through the ceramic sleeve 22 and is clamped at the bottom of the ceramic sleeve 22 through the upper hollow cylinder.
A second threaded hole is formed in the upper portion of the tungsten wire base 24, second threads are formed in the bottom of a lower hollow cylinder of the copper bolt 23, and the bottom of the copper bolt 23 is fixed to the upper portion of the tungsten wire base 24 through the second threaded hole and the second threads.
Further, as shown in fig. 6, the tungsten wire 25 is spiral in the horizontal plane, two ends of the spiral tungsten wire 25 extend out of a section of tungsten wire for fixing on the vertical plane, and the tungsten wire 25 is fixed on the lower portion of the tungsten wire base 24 through a pressing block 240.
The lower part of the tungsten filament base 24 and the pressing block 240 are respectively provided with a third threaded hole, the lower part of the tungsten filament base 24 and the pressing block 240 are fixed together in a bolt perforation manner, and the tungsten filament 25 is fixed between the lower part of the tungsten filament base 24 and the pressing block 240.
Further, a wire groove is formed in the surface of the pressing block 240, the wire groove is vertically downward, and the wire groove is used for placing the tungsten filament 25 and fixing the tungsten filament 25 between the pressing block 240 and the lower portion of the tungsten filament base 24.
Further, the emitter 2 is provided with a conducting wire 26, the conducting wire 26 is used for being externally connected with a direct current voltage stabilizing source, and the direct current voltage stabilizing source is used for controlling the current density of the electron beam.
In practical applications, the wire 26 is a 6-plane copper core for passing large current. The current density of an electron beam is the number of electrons, and the larger the number of electrons in a certain space, the larger the current density. Electrons are mainly emitted through the tungsten filament 25, and if the quantity of the electrons emitted by the tungsten filament 25 is to be controlled, the current applied to the tungsten filament 25 is mainly controlled, namely the magnitude of an external direct current voltage stabilizing source is controlled. Through tests, the electron gun disclosed by the embodiment of the application can realize the current density of 0-30A/cm2The inner part is continuously adjustable.
Further, the lead wire 26 is inserted into the metal sleeve 21 and the ceramic sleeve 22 and fixed to the inside of the copper pin 23.
A fourth threaded hole is formed in the lower hollow cylinder of the copper bolt 23, and the lead 26 is fixed inside the lower hollow cylinder of the copper bolt 23 through a bolt 27 and the fourth threaded hole.
The lead 26 is used for providing current for the tungsten filament 25, so that the tungsten filament 25 generates heat and then emits electrons, the tungsten filament 25 is fixed on the copper bolt 23 through the tungsten filament base 24, the tungsten filament base is made of conductive metal materials, and the copper bolt 23 is also conductive, so that the current can be provided for the tungsten filament 25 only by fixing the lead 26 in the copper bolt 23.
Specifically, through the controllable electron gun of electron energy that this application discloses, the process of launching the electron beam is, direct current steady voltage source applys the electric current to projecting pole 2 through the wire for tungsten filament 25 generates heat, when the temperature of tungsten filament 25 reaches a definite value, for example reach 1000 degrees centigrade, tungsten filament 25 can launch a large amount of electrons, these electrons belong to the free state, stray is indefinite, exert negative high voltage through high voltage power supply at this moment on control utmost point 3, make and become an electric field between control utmost point 3 and the earthing pole, under the effect of electric field force, the electron begins the downstream, the gathering forms the electron beam, after being exerted positive high voltage focus utmost point 4, the beam diameter of electron beam is retrained, hit in the surface of the sample that is surveyed. In the process of downward movement of the electrons, the higher the speed is, the higher the energy of the formed electrons is, the greater the depth of the electrons hitting the tested sample is, and the more favorable the test of the charge characteristics to be carried out is. Therefore, the electron energy of the electron beam needs to be controlled, at this time, the electron energy of the electron beam is regulated and controlled mainly by controlling the size of the electric field between the control electrode 3 and the grounding electrode, that is, the field intensity of the electron, and during the specific operation, the moving speed of the electron can be increased by only controlling the size of the high-voltage power supply and increasing the size of the absolute value of the negative high voltage applied to the control electrode 3, so that the electron energy of the electron beam is further increased. Through testing, the electron gun with the controllable electron energy disclosed by the application has the advantages that the electron energy can be continuously adjusted between 0 and 30KeV, and the adjustment precision of the electron energy reaches 0.01 KeV.
In the charge characteristic test of the dielectric material, the depth of the electron beam striking the inside of the tested sample is related to energy, the quantity of electrons is related to current density, and in order to research the charge characteristic of the dielectric material at different depths, the electron beam with accurately controllable current density and energy is needed. In order to make a certain number of electrons enter the dielectric medium at different depths, the method is mainly realized by two aspects, namely, by controlling the current density of the electron beam, the larger the current density of the electron beam is, the more the number of electrons entering the inside of a tested sample is; secondly, by controlling the electron energy of the electron beam, electrons with larger electron energy are easier to enter the tested sample. In addition, the position of the electron beam on the sample to be tested is controlled by controlling the beam diameter of the electron beam, and the smaller the beam diameter of the electron beam is, the more concentrated the electron energy of the electron beam is, and the more accurate the position of the electron beam on the sample to be tested is. In the electron gun in the prior art, the electron energy and the current density cannot be effectively and accurately regulated, the emitted electron beam is unstable, electrons are distributed in the material longitudinally in a disordered manner, and the charge characteristics of the medium material at different depths cannot be effectively researched. Therefore, compared with the prior art, the electron gun disclosed by the embodiment of the application can effectively and accurately regulate and control the electron energy and the current density of the electron beam, so that a certain number of electrons can be accurately shot at a certain depth in a tested sample, and the accuracy of the charge characteristic test of the dielectric material is effectively improved.
In addition, according to the electron gun with controllable electron energy, the epoxy support columns 12 are arranged, the shape and the position of the ceramic sleeve 22 are designed ingeniously, the insulation effect of the electron gun is enhanced to a great extent, and the heat resistance of the electron gun is effectively improved.
Further, the upper portion of the control electrode 3 is a first circular ring, two first fixing holes are formed in the first circular ring, the two first fixing holes are symmetrical with respect to the circle center of the first circular ring, and the first fixing holes are used for penetrating through the epoxy support column 12 and fixing the control electrode 3 on the epoxy support column 12 through epoxy nuts.
The lower part of the control electrode 3 is a thin-wall cylinder, and the diameter of the thin-wall cylinder is equal to the inner diameter of the first circular ring.
The spiral plane of the tungsten filament 25 extends into the thin-walled cylinder, and the electron beam emitted by the tungsten filament 25 is controlled through the thin-walled cylinder.
The tungsten filament 25 extends into the thin-wall cylinder, so that the control electrode 3 can control the electrons just emitted by the tungsten filament 25, prevent the electrons from dissociating outside, and play a role in controlling the quantity of emitted electrons and focusing electron beams.
Furthermore, the upper portion of the focusing electrode 4 is of a horn-type opening structure, and the inner diameter of the horn-type opening structure is gradually increased from top to bottom, so that the electron beam can be focused.
The electron beam passes through the control electrode 3, is emitted downwards in a trumpet shape under the action of field intensity, and then the beam diameter of the electron beam is restricted through the upper part of the focusing electrode 4 applied with positive pressure, so that the electron beam is not scattered, and the electron beam can be intensively irradiated on a tested sample.
The lower part of the focusing electrode 4 is a second circular ring, the inner diameter of the second circular ring is equal to the maximum inner diameter of the upper part of the focusing electrode 4, the second circular ring is provided with two second fixing holes, the two second fixing holes are symmetrical about the circle center of the second circular ring, and the second fixing holes are used for penetrating through the epoxy support column 12 and fixing the focusing electrode 4 on the epoxy support column 12 through epoxy nuts.
The present application has been described in detail with reference to specific embodiments and illustrative examples, but the description is not intended to limit the application. Those skilled in the art will appreciate that various equivalent substitutions, modifications or improvements may be made to the presently disclosed embodiments and implementations thereof without departing from the spirit and scope of the present disclosure, and these fall within the scope of the present disclosure. The protection scope of this application is subject to the appended claims.
Claims (7)
1. An electron gun with controllable electron energy, comprising: the electron beam generating device comprises an insulating support (1), an emitting electrode (2), a control electrode (3) and a focusing electrode (4), wherein the emitting electrode (2) is used for emitting an electron beam, the control electrode (3) is used for controlling the electron energy of the electron beam, and the focusing electrode (4) is used for controlling the beam diameter of the electron beam;
the insulating support (1) comprises a ceramic circular plate (11) and an epoxy support column (12), the top end of the epoxy support column (12) is fixed at the edge of the ceramic circular plate (11), the emitter (2) is installed on the ceramic circular plate (11), the control electrode (3) and the focusing electrode (4) are respectively fixed on the epoxy support column (12), the control electrode (3) is positioned below the emitter (2), the focusing electrode (4) is positioned below the control electrode (3), and a sample to be tested is positioned below the focusing electrode (4);
the control electrode (3) and the focusing electrode (4) are externally connected with a high-voltage power supply, the high-voltage power supply is used for applying negative high voltage to the control electrode (3) so that an electric field is formed between the control electrode (3) and a grounding electrode positioned below the sample to be tested, the electric field is used for controlling the electron energy of the electron beam, the high-voltage power supply is also used for applying positive high voltage to the focusing electrode (4), and the focusing electrode controls the beam diameter of the electron beam through the positive high voltage;
the emitter (2) comprises a metal block (20), a metal sleeve (21), a ceramic sleeve (22), a copper bolt (23), a tungsten wire base (24) and a tungsten wire (25);
the metal sleeve (21) and the metal block (20) are used for mounting the emitter (2) on the ceramic circular plate (11), the ceramic sleeve (22) is positioned inside the metal sleeve (21), the ceramic sleeve (22) is used for realizing electrical isolation, one end of the copper bolt (23) is positioned inside the ceramic sleeve (22), the other end of the copper bolt (23) extends out of the metal sleeve (21) and the ceramic sleeve (22) and is fixed with the upper part of the tungsten filament base (24), the tungsten filament (25) is fixed on the lower part of the tungsten filament base (24), and the electron beam is emitted from the tungsten filament (25);
the emitter (2) is provided with a lead (26), the lead (26) is used for being externally connected with a direct current voltage stabilizing source, and the direct current voltage stabilizing source is used for controlling the current density of the electron beam;
the lead (26) penetrates into the metal sleeve (21) and the ceramic sleeve (22) and is fixed inside the copper bolt (23);
a fourth threaded hole is formed in the lower hollow cylinder of the copper bolt (23), and the lead (26) is fixed inside the lower hollow cylinder of the copper bolt (23) through a bolt (27) and the fourth threaded hole.
2. Electron gun according to claim 1, characterized in that the metal block (20) is a stainless steel metal square and the metal sleeve (21) is a stainless steel metal sleeve.
3. The electron gun according to claim 1, wherein two circular holes are opened on the plate surface of the ceramic circular plate (11), the two circular holes are symmetrical about the center of the ceramic circular plate (11), two first threaded holes are opened on the metal block (20), two metal sleeves (21) are provided, a first thread is provided on the top end of each metal sleeve (21), and the top end of each metal sleeve (21) passes through the two circular holes to be mounted on the ceramic circular plate (11) after being connected with the metal block (20) through the first threaded holes and the first thread;
the metal sleeve (21) is of a hollow structure, the outer diameter of the bottom of the metal sleeve (21) is equal to the outer diameter of the upper part of the metal sleeve, the inner diameter of the bottom of the metal sleeve (21) is smaller than the inner diameter of the upper part of the metal sleeve, and the bottom of the metal sleeve (21) is used for clamping the ceramic sleeve (22);
the ceramic sleeve (22) is of a hollow structure, the outer diameter of the bottom of the ceramic sleeve (22) is smaller than the outer diameter of the upper part of the ceramic sleeve, the outer diameter of the upper part of the ceramic sleeve (22) is smaller than the inner diameter of the upper part of the metal sleeve (21), the outer diameter of the upper part of the ceramic sleeve (22) is larger than the inner diameter of the bottom of the metal sleeve (21), the ceramic sleeve (22) penetrates into the metal sleeve and is clamped at the bottom end of the metal sleeve (21), and the inner diameter of the bottom of the ceramic sleeve (22) is smaller than the inner diameter of the upper part of the ceramic sleeve (22) and;
the copper bolt (23) is of a hollow structure, the copper bolt (23) comprises an upper hollow cylinder and a lower hollow cylinder, the inner diameters of the upper hollow cylinder and the lower hollow cylinder are equal, the outer diameter of the upper hollow cylinder is larger than that of the lower hollow cylinder, the outer diameter of the upper hollow cylinder is smaller than that of the upper part of the ceramic sleeve (22), the outer diameter of the upper hollow cylinder is larger than that of the bottom of the ceramic sleeve (22), and the copper bolt (23) penetrates into the ceramic sleeve (22) and is clamped at the bottom of the ceramic sleeve (22) through the upper hollow cylinder;
and a second threaded hole is formed in the upper part of the tungsten wire base (24), second threads are arranged at the bottom of the lower hollow cylinder of the copper bolt (23), and the bottom of the copper bolt (23) is fixed with the upper part of the tungsten wire base (24) through the second threaded hole and the second threads.
4. The electron gun according to claim 1, wherein the tungsten wire (25) is spiral in horizontal plane, two ends of the spiral tungsten wire (25) extend out of a section of tungsten wire for fixing in vertical plane, and the tungsten wire (25) is fixed at the lower part of the tungsten wire base (24) through a pressing block (240);
the lower part of the tungsten filament base (24) and the pressing block (240) are respectively provided with a third threaded hole, the lower part of the tungsten filament base (24) and the pressing block (240) are fixed together in a bolt perforation mode, and the tungsten filament (25) is fixed between the lower part of the tungsten filament base (24) and the pressing block (240).
5. The electron gun according to claim 4, characterized in that the pressing block (240) is provided with a wire groove on the surface, the direction of the wire groove is vertical downward, the wire groove is used for placing the tungsten filament (25) and fixing the tungsten filament (25) between the pressing block (240) and the lower part of the tungsten filament base (24).
6. The electron gun according to claim 4, wherein the upper portion of the control electrode (3) is a first circular ring, and two first fixing holes are formed in the first circular ring, and are symmetrical with respect to the center of the first circular ring, and the first fixing holes are used for passing through the epoxy support column (12) and fixing the control electrode (3) on the epoxy support column (12) through epoxy nuts;
the lower part of the control electrode (3) is a thin-wall cylinder, and the diameter of the thin-wall cylinder is equal to the inner diameter of the first circular ring;
the spiral plane of the tungsten filament (25) extends into the thin-wall cylinder, and the electron beam emitted by the tungsten filament (25) is controlled through the thin-wall cylinder.
7. The electron gun according to claim 1, wherein the upper portion of the focusing electrode (4) is in a trumpet-shaped opening structure, and the inner diameter of the trumpet-shaped opening structure is gradually increased from top to bottom;
the lower part of the focusing electrode (4) is a second circular ring, the inner diameter of the second circular ring is equal to the maximum inner diameter of the upper part of the focusing electrode (4), two second fixing holes are formed in the second circular ring, the two second fixing holes are symmetrical about the circle center of the second circular ring, and the second fixing holes are used for penetrating through the epoxy support column (12) and fixing the focusing electrode (4) on the epoxy support column (12) through epoxy nuts.
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104319217A (en) * | 2014-10-20 | 2015-01-28 | 大连交通大学 | Low-energy electronic gun |
| CN207458884U (en) * | 2017-08-25 | 2018-06-05 | 金华职业技术学院 | A kind of Plasma-cathode e-gun |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104319217A (en) * | 2014-10-20 | 2015-01-28 | 大连交通大学 | Low-energy electronic gun |
| CN207458884U (en) * | 2017-08-25 | 2018-06-05 | 金华职业技术学院 | A kind of Plasma-cathode e-gun |
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