CN104538272B - A kind of cold cathode X-ray tube negative electrode - Google Patents
A kind of cold cathode X-ray tube negative electrode Download PDFInfo
- Publication number
- CN104538272B CN104538272B CN201410781359.7A CN201410781359A CN104538272B CN 104538272 B CN104538272 B CN 104538272B CN 201410781359 A CN201410781359 A CN 201410781359A CN 104538272 B CN104538272 B CN 104538272B
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- China
- Prior art keywords
- negative electrode
- grid
- cathode
- pedestal
- electrode pedestal
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Classifications
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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
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J35/00—X-ray tubes
- H01J35/24—Tubes wherein the point of impact of the cathode ray on the anode or anticathode is movable relative to the surface thereof
Abstract
The present invention provides a kind of cold cathode X-ray tube negative electrode, including a negative electrode pedestal, the negative electrode pedestal is made up of upper and lower two cylinders being coaxially disposed, section is in "convex" shaped, and a cathode bar through hole is offered on the central axis of negative electrode pedestal, and cathode bar is provided with through hole；The three-dimensional dimension of the cathode bar is controllable, and electron emitter is set in cathode taps；Including a grid, the grid be cup-like structure, it is internal offer a "convex" shaped groove supporting with negative electrode pedestal, the negative electrode pedestal can nesting to be arranged at gate recess interior and do not contacted with grid inwall；The grid center sets an electronic transmission hole for the electronics emitted for beam forming cathode of half-conical；By the use of carbon nanomaterial cold cathode as the X-ray tube of electron emission source, negative electrode can be effectively controlled to prepare and emission area by the size of cathode bar；And three-pole structure is used, and focused on by grid, small focus is capable of achieving, improve the resolution ratio of x-ray imaging.
Description
Technical field
The present invention relates to a kind of X-ray tube, and in particular to a kind of cold cathode X-ray tube negative electrode.
Background technology
X-ray tube is a kind of device for realizing the controllable transmitting of X-ray.They are applied in various systems, for example, using
In the x-ray imaging technology in the fields such as medical treatment, industry and safety, spectrum analysis (X-ray fluorescence spectra, x-ray photoelectron energy
Analysis of spectrum), X-ray diffraction analysis etc..The principle that X-ray is produced in X-ray tube is to utilize high energy electron (tens of thousands of electron-volts),
Bombardment metallic target, the interaction between these electronics and target is doubled, until sending X-ray.X-ray intensity with reach target
Electron stream on material is directly proportional.The penetrability of X-ray is directly proportional to the applied voltage on target material.The emission area of X-ray
Determined by the scope of beam bombardment target, the general electron-optical arrangement by X-ray tube can exist Electron Beam Focusing
The region of very little on target, small transmitting focal spot is formed with this.
Conventional X-ray tubes typically use hot cathode, and thousands of celsius temperatures are reached by the wire in heating, vacuum pipe
To produce high energy electron.But hot cathode is present, and volume is larger, electron emission modulates the time (millisecond rank) more long, power consumption is big etc. lacks
Fall into.For these defects of hot cathode, the research of the cold cathode of function admirable is arisen at the historic moment.At room temperature, negative electrode is in electric field action
Lower launching electronics (referred to as Flied emission), therefore Flied emission has capacity usage ratio higher.Additionally, Flied emission also has some only
Special property, for example, to the quick response of electric field change, to temperature fluctuation and insensitive, the electron beam height launched of radiation
It is controllable, on-off ratio high, the ballistic transport of electronics, and also the voltage modulated scope of very little can just modulate very big current range.
Carbon nanomaterial is a kind of allotrope of carbon, is quasi-one-dimensional nanometer material.Due to draw ratio higher,
The chemistry and mechanical performance of stabilization, therefore with outstanding field emission performance.For example, low turn-on voltage, electron emission high stabilization
Property, long-life etc..In recent years, carbon nanomaterial is applied to the focus that feds have become research.
The content of the invention
The present invention seeks to：It is the resolution ratio of raising x-ray imaging, and shortens the time for exposure of X-ray, the present invention is carried
For a kind of X-ray tube cathode by the use of carbon nanomaterial cold cathode as electron emission source, the three-dimensional dimension of cathode bar is controllable, leads to
Crossing the size of cathode bar can effectively control negative electrode to prepare and emission area；Emission p erformance is good, electric current stabilization；And use three poles
Formula structure, is focused on by grid, is capable of achieving small focal spot, improves the resolution ratio of x-ray imaging, and can under high voltages can be steady
Fixed work a period of time；They are applied in various systems, for example, the X for being applied to the fields such as medical treatment, industry and safety is penetrated
Line imaging technology, spectrum analysis (X-ray fluorescence spectra, X-ray photoelectron spectroscopic analysis), X-ray diffraction analysis etc..
The technical scheme is that：A kind of cold cathode X-ray tube negative electrode, including a negative electrode pedestal, the negative electrode base
Seat is made up of upper and lower two cylinders being coaxially disposed, section is in "convex" shaped, and one is offered on the central axis of negative electrode pedestal
Individual cathode bar through hole, is provided with cathode bar in through hole；The three-dimensional dimension of the cathode bar is controllable, and electronics hair is set in cathode taps
Beam；
Including a grid, the grid is cup-like structure, inside offers " convex " word supporting with negative electrode pedestal
Connected in star, the negative electrode pedestal can nesting be arranged in gate recess and do not contacted with grid inwall；The grid center sets one
The electronic transmission hole of the electronics emitted for beam forming cathode of individual half-conical；
Including a flat board stem, the flat board stem includes a supporting plate and a double glazing stem；Supporting plate
On be provided with the connecting pole for being connected and fixing with negative electrode pedestal and the conductive pole being connected respectively on grid and negative electrode, conductive pole is another
One end is connected to the external power supply of X-ray tube, and grid connects high pressure, minus earth.
Further, it is provided with a circle air-breathing between the top small cylinder circumference and grid madial wall of the negative electrode pedestal
Agent；Getter is attached to grid inwall, forms one layer of structure of hollow columnar, is discharged at work for uniform pickup part
Gas, keeps the vacuum needed for electronic field emission in X-ray tube, extends cathode electronics emission lifetime.
Further, the 2-5 pedestal that offer symmetrical on the negative electrode pedestal installs fixed via, and pedestal is installed and fixed
Through hole both sides are respectively provided with a T-shaped hollow insulating ceramics, in the vertical end insertion through hole of the T-shaped hollow insulating ceramics, water
Flush end is placed on outside makes negative electrode pedestal and gate insulator；It is right on grid that fixing bolt is fixed on through T-shaped hollow insulating ceramics
In the screw that title is opened up, make negative electrode pedestal coaxially connected with grid.By fixing bolt and hollow T-shaped ceramics, negative electrode pedestal and
There is good bonding strength and positioning precision between grid.
Further, three positions of mounting hole of negative electrode base side face correspondence, offer three through hole gas ports.Make
Vacuum is pumped more thorough.Because there is gap, gap after two symmetrical T-shaped hollow insulating ceramics docking and in the middle of negative electrode pedestal
In air by aperture exclude, T-shaped hollow insulating ceramics be T-shaped aluminium oxide ceramics.
Further, the assembling of X-ray tube for convenience, the grid outside is arranged with a grid cover for cup-shaped, closes
Into an encapsulated space, the space can encapsulate grid and negative electrode pedestal.And grid cover center offers a grid cover beam orifice.
Further, a conductive pole is also set up in the supporting plate and can be used for expanded function.
The beneficial effects of the invention are as follows：
Firstth, X-ray tube cathode realizes cold cathode emission, overcomes Coolidge tube and has that volume is larger, electronics hair
Penetrate the defect problems such as modulation time (millisecond rank) more long, power consumption be big.Realize that booting moment electric field opens launching electronics, shorten X
The time for exposure of ray；Can be widely used in various systems, for example, being applied to the X in the fields such as medical treatment, industry and safety
Radiographic techniques, spectrum analysis (X-ray fluorescence spectra, X-ray photoelectron spectroscopic analysis), X-ray diffraction analysis etc..
Secondth, carbon nano material is quasi-one-dimensional nanometer material.Due to draw ratio higher, the chemistry of stabilization and mechanicalness
Can, therefore with outstanding field emission performance.For example, low turn-on voltage, electron emission stability high, long-life etc..
3rd, in the X-ray tube cathode of x-ray imaging equipment, negative electrode can be effectively controlled to prepare by the size of cathode bar
And emission area.Emission p erformance is good, electric current stabilization, and uses three-pole structure, is focused on by grid, is capable of achieving Xiao Jiao
Point, improves the resolution ratio of x-ray imaging, and can under high voltages can be with steady operation for a period of time.
4th, using getter, X-ray tube internal vacuum can be effectively maintained, is conducive to extending the use (work of cold cathode
Make) life-span.
4th, overall structure is simple, can Function Extension, and then the development and maintenance cost of x-ray imaging equipment can be reduced.
Brief description of the drawings
Fig. 1 is the explosive view of cold cathode X-ray tube negative electrode of the present invention；
Fig. 2 is the installation diagram of cold cathode X-ray tube negative electrode of the present invention；
Fig. 3 is the structural representation of T-shaped hollow insulating ceramics；
Fig. 4 is the installation diagram of T-shaped hollow insulating ceramics.
In figure：1 is flat board stem, 2 is conductive pole, 3 is connecting pole, 4 is fixing bolt, 5 is T-shaped hollow insulating ceramics, 6
For negative electrode pedestal, 7 be pedestal install fixed via, 8 be through hole gas port, 9 be cathode bar through hole, 10 be getter, 11 for the moon
Pole rod, 12 be grid, 13 be screw, 14 be electronic transmission hole, 15 be grid cover, 16 be grid cover beam orifice.
Specific embodiment
The present invention is further illustrated below in conjunction with the accompanying drawings.
As shown in Figure 1, 2, a kind of cold cathode X-ray tube negative electrode, including a negative electrode pedestal 6, the negative electrode pedestal 6 is by upper
Lower two cylinder composition, the sections being coaxially disposed offer a negative electrode in "convex" shaped on the central axis of negative electrode pedestal 6
Rod through hole 9 (cathode aperture is circular or square, and the cathode size of aperture size emission current according to actual needs is determined), through hole
Inside it is provided with cathode bar 11；The three-dimensional dimension of the cathode bar is controllable, can effectively control negative electrode to prepare by the size of cathode bar
And emission area, electron emitter is prepared by physico-chemical process in cathode taps.
Including a grid 12, the grid 12 be cup-like structure, it is internal offer one it is supporting with negative electrode pedestal
"convex" shaped groove, the negative electrode pedestal 6 can nesting be arranged in gate recess and do not contacted with grid inwall；The grid 12
Center sets an electronic transmission hole 14 for half-conical, for the electronics that beam forming cathode is emitted, and allows electronics to pass through beam orifice
Directive anode.Emission principle is the field emission of electronics：Grid connects high pressure, minus earth.Space electricity between negative electrode and grid
Field reduces the work function of electronics, so as to realize that high current is launched under existing fringing field.The die opening of grid and negative electrode is by transmitting electricity
The emitter pattern of son, highly determines.
A circle getter 10 is provided between the top small cylinder circumference and grid madial wall of negative electrode pedestal；Getter is attached
In grid inwall, form one layer of structure of hollow columnar, for the gas that uniform pickup part discharges at work, keep X
Vacuum in ray tube needed for electronic field emission, extends cathode electronics emission lifetime.
Symmetrical 3 pedestals that offer install the fixed via (number of pedestal installation fixed via on the negative electrode pedestal 6
At 2-5), pedestal installs fixed via both sides and is respectively provided with a T-shaped hollow insulating ceramics 5 (as shown in Figure 3), described
The vertical end of T-shaped hollow insulating ceramics 5 is inserted in through hole, horizontal ends are placed on outside makes negative electrode pedestal and gate insulator；It is fixed
Bolt 4 is fixed on grid in the symmetrical screw 13 for opening up through T-shaped hollow insulating ceramics, makes negative electrode pedestal coaxial with grid
(central shaft) is connected.There is good bonding strength by fixing bolt and hollow T-shaped ceramics, between negative electrode pedestal and grid and determine
Position precision.
As shown in figure 4, three positions of mounting hole of the side of negative electrode pedestal 6 correspondence, offer three through hole gas ports
8, it is pumped vacuum more thorough.Because there is gap after two symmetrical T-shaped hollow insulating ceramics docking and in the middle of negative electrode pedestal,
Air in gap is excluded by aperture, and T-shaped hollow insulating ceramics is T-shaped aluminium oxide ceramics.
The assembling of X-ray tube for convenience, in a kind of its exemplary embodiment, the outside of the grid 12 is arranged with one
The grid cover 15 of individual cup-shaped, synthesizes an encapsulated space, and the space can encapsulate grid and negative electrode pedestal.And grid cover center opens up
There is a grid cover beam orifice 16.
Including a flat board stem 1, the flat board stem 1 includes one double glazing stem of a supporting plate.Supporting plate
On be respectively arranged with three connecting poles 3 and three conductive poles 2, three connecting poles are connected and fix with negative electrode pedestal, three wires
Post two of which one end by can valve silk (conducting metal) be connected respectively on grid and negative electrode, the other end is connected to X and penetrates
The external power supply of spool, high voltage is provided by power supply to grid.3rd can be used for expanded function.
In the cold cathode X-ray tube negative electrode, cathode emissive area can be control effectively by the size of cathode bar, three poles
Formula structure, is focused on by grid, is capable of achieving small focus.Overall structure is simple, so can reduce x-ray imaging equipment exploitation and
Maintenance cost.
The X-ray tube cathode of x-ray imaging equipment as described above, the grid, negative electrode pedestal, connecting pole, conductive pole,
The materials such as bolt are the consistent or approximate metal material of thermal coefficient of expansion.
The negative electrode bar material be containing can be catalyzed the metal or metallic compound that prepare emitter, such as common iron, cobalt,
Nickel, waits pure metal catalyst or the compound containing catalyst metals etc..Transmitting preparation is physical vapour deposition (PVD), chemical gas
Mutually deposit, silk-screen printing, solwution method etc..Generally transmitting body thickness is tens microns.
It should be pointed out that for those skilled in the art, under the premise without departing from the principles of the invention,
Some improvements and modifications can also be made, these improvements and modifications also should be regarded as protection scope of the present invention.In the present embodiment not
Clear and definite each part can use prior art to be realized.
Claims (3)
1. a kind of cold cathode X-ray tube negative electrode, it is characterised in that：Including a negative electrode pedestal (6), the negative electrode pedestal (6) by
Upper and lower two cylinder composition, the sections being coaxially disposed offer one in "convex" shaped on the central axis of negative electrode pedestal (6)
Cathode bar through hole (9), is provided with cathode bar (11) in through hole；The three-dimensional dimension of the cathode bar is controllable, and is set in cathode taps
Electron emitter；
Including a grid (12), the grid (12) is cup-like structure, it is internal offer one it is supporting with negative electrode pedestal
"convex" shaped groove, the negative electrode pedestal (6) can nesting be arranged in gate recess and do not contacted with grid inwall；The grid
(12) center sets an electronic transmission hole (14) for the electronics emitted for beam forming cathode of half-conical；
Including a flat board stem (1), the flat board stem (1) includes a supporting plate and a double glazing stem；Support
The connecting pole (3) for being connected and fixing with negative electrode pedestal and the conductive pole (2) being connected respectively on grid and negative electrode are provided with plate,
Conductive pole (2) other end is connected to the external power supply of X-ray tube, and grid connects high pressure, minus earth；
The symmetrical 2-5 pedestal that offer installs fixed via on the negative electrode pedestal (6), and it is each that pedestal installs fixed via both sides
One T-shaped hollow insulating ceramics (5) is installed, in the vertical end insertion through hole of the T-shaped hollow insulating ceramics (5), horizontal ends
Being placed on outside makes negative electrode pedestal and gate insulator；Fixing bolt (4) is fixed on grid symmetrically through T-shaped hollow insulating ceramics
In the screw (13) for opening up, make negative electrode pedestal coaxially connected with grid；
A circle getter (10) is provided between the top small cylinder circumference and grid madial wall of the negative electrode pedestal (6)；
The grid (12) outside is arranged with a grid cover for cup-shaped (15), and to offer a grid cover saturating at grid cover center
Perforation (16).
2. a kind of cold cathode X-ray tube negative electrode according to claim 1, it is characterised in that：Negative electrode pedestal (6) side
Three positions of mounting hole of correspondence, offer three through hole gas ports (8).
3. a kind of cold cathode X-ray tube negative electrode according to claim 1, it is characterised in that：Also set up in the supporting plate
One conductive pole can be used for expanded function.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410781359.7A CN104538272B (en) | 2014-12-16 | 2014-12-16 | A kind of cold cathode X-ray tube negative electrode |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410781359.7A CN104538272B (en) | 2014-12-16 | 2014-12-16 | A kind of cold cathode X-ray tube negative electrode |
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| Publication Number | Publication Date |
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| CN104538272A CN104538272A (en) | 2015-04-22 |
| CN104538272B true CN104538272B (en) | 2017-06-13 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201410781359.7A Expired - Fee Related CN104538272B (en) | 2014-12-16 | 2014-12-16 | A kind of cold cathode X-ray tube negative electrode |
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Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108962707B (en) * | 2018-08-16 | 2023-11-28 | 成都凯赛尔电子有限公司 | Micro-focus cold cathode focusing structure and mounting method thereof |
| CN110676144B (en) * | 2019-09-17 | 2022-01-21 | 中国科学院国家空间科学中心 | Cathode structure of X-ray tube |
| CN110824572A (en) * | 2019-11-12 | 2020-02-21 | 倪其棍 | X-ray imaging equipment |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| KR100911434B1 (en) * | 2007-12-17 | 2009-08-11 | 한국전자통신연구원 | The compactive x-ray tube with triode structure using cnt |
| KR101247453B1 (en) * | 2011-08-18 | 2013-03-25 | 경희대학교 산학협력단 | A X-ray source having the cooling and shielding function |
| CN103413745B (en) * | 2013-07-24 | 2016-04-20 | 南京康众光电科技有限公司 | A kind of grid-control cold cathode X-ray tube |
| CN204257584U (en) * | 2014-12-16 | 2015-04-08 | 南京康众光电科技有限公司 | A kind of cold cathode X-ray tube negative electrode |
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