CN210009041U - Local secondary fluorescent radiation X-ray bulb tube - Google Patents

Abstract

The utility model discloses a local secondary fluorescence radiation X bulb, include: a vacuum tube; the filament emitter is arranged in the vacuum tube and used for emitting electrons; the focalizer is arranged in the vacuum tube and is used for gathering electrons emitted by the filament emitter into an electron beam; the target assembly is arranged on the vacuum tube and comprises a main target and an auxiliary target which are sequentially arranged along the emission direction of the electron beam, and the thickness of the main target is smaller than that of the auxiliary target; the electron beam produces a small or dispersed focus on the primary target. The utility model discloses the electron that the focuser made the filament transmitter send is gathered together and is formed X ray on the main target of target subassembly, and X ray can directly arouse secondary fluorescence locally through vice target, and energy conversion is high, need not high power input and just can realize high brightness, can realize the formation of microfocus, and energy conversion is high to make the volume and the power of bulb can be very little, simplifies application scene by a wide margin.

Description

Local secondary fluorescent radiation X-ray bulb tube

Technical Field

The utility model relates to a local secondary fluorescence radiation X bulb.

Background

X-ray generation is achieved by striking the target with electrons, and typically includes both continuous (Bremsstrahlung) and characteristic lines. If the incident electron energy is high enough, a characteristic line is developed. The energy distributions of the two lines are about 70% and 30% depending on the electron energy. The continuum is due to the redirection of electron impact on the atoms and the release of energy losses. The characteristic spectral line is released in the form of X-ray due to energy loss caused by transition of outer layer electrons caused by electron knocking off inner core electrons of atoms. Since the transition energy difference is fixed, the energy of the X-ray is also correspondingly fixed. The traditional coolridge bulb is dominated by the use of Bremsstrahlung radiation. The application of the traditional secondary fluorescence is generally limited to material detection according to a characteristic spectral line. In this application, since the second target is at a relatively large X-ray distance from the first target, a significant amount of X-rays are already attenuated by scattering and shielding, and the remaining rays strike the second target very weakly. These characteristic rays can be detected by a detector at a short distance for material analysis, but the light intensity is weak, and the imaging again is not possible.

The conventional kurzki bulb cannot effectively utilize secondary fluorescence. First, the main Bremsstrahlung emission has a forward orientation with respect to the electron beam, and thus the solid angle subtended by the majority of the X-ray flux obtained emerging from the side window is small and also a result of the primary radiation. The secondary fluorescence results are mostly masked and essentially do not exit the side window. Secondly, gratings are also commonly used in order to concentrate the X-ray spectrum at the energy level best suited for target thickness and density. Although the grid preferentially absorbs photon flux with higher and lower energy fractions, it is far less efficient than local fluorescence for energy conversion and filtering due to the greater distance, and it further reduces the brightness of the photon flux in the desired energy window.

In a typical fluorescent radiation design, electrons in a bulb strike a primary target to obtain conventional X-rays, which are then used to further irradiate a distant secondary target to generate secondary fluorescent radiation. In the most common application of material component detection, the detected object actually serves as a secondary target, and the emitted secondary fluorescence can be qualitatively and quantitatively determined by using a detector, so that the component of the detected object is determined (see fig. 1).

The applicant aims to design a local secondary fluorescence radiation X-ray tube that achieves X-rays dominated by fluorescence lines by localizing the process of secondary fluorescence radiation. An example of the use of fluorescence line-dominant rays in the case of non-destructive detection (see FIG. 2). The traditional fluorescence is used for detecting the components of an object, and the two targets are far away from each other. Because the use energy efficiency of the traditional Kurqi bulb is low, the brightness irradiated to the auxiliary target material is not high, and the efficiency of generating secondary fluorescence is further low. The weak fluorescence is not easy to be used for other purposes except that a detector is used for directly carrying out qualitative and quantitative material detection. The conventional Cocquette has 60% of the electron energy converted into heat energy, 39% reflected, and only 1% converted into X-rays (see FIG. 3). Only 0.03% of the 1% is used, while most of the others are shielded from the radiation protective material and are not used. The secondary fluorescence generated when the small amount of light irradiates the object to be measured is very weak.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a can high-energy-efficient launch the local secondary fluorescence radiation X bulb of the ray that gives first place to with local fluorescence radiation.

Realize the utility model discloses the technical scheme of purpose is: a local secondary fluorescent radiation X-ray tube comprising:

a vacuum tube;

the filament emitter is arranged in the vacuum tube and used for emitting electrons;

the focalizer is arranged in the vacuum tube and is used for gathering electrons emitted by the filament emitter into an electron beam; the target assembly is arranged on the vacuum tube and comprises a main target and an auxiliary target which are sequentially arranged along the emission direction of the electron beam, and the thickness of the main target is smaller than that of the auxiliary target; the electron beam produces a small or dispersed focus on the primary target.

The vacuum tube comprises a ceramic tube and a shell; the shell is used for sealing the ceramic tube; the filament emitter and the focalizer are both arranged in the ceramic tube; the target assembly is arranged at one end of the shell and is aligned with the filament emitter.

And an insulating material is filled between the shell of the vacuum tube and the ceramic tube.

The radiation-proof shield is sleeved on the outer wall of the vacuum tube and used for shielding redundant radiation and restraining the radiation angle of the target material component.

One end of the radiation-proof shielding cover close to the target assembly is provided with a restraining part for restraining the radiation angle of the target; the constraint part is annular, and the target assembly is positioned at the axis of the constraint part; the inner diameter of the restriction part is gradually increased from the inside to the outside.

The high-voltage electric module is arranged between the ceramic tube of the vacuum tube and the shell; the target assembly, the filament emitter and the focalizer are electrically connected with the high-voltage electric module respectively, and the target assembly and the filament emitter form potential difference.

The focuser presses electrons released by the filament emitter through voltage to limit the electrons in a narrow traveling angle, so that electron beams are formed and strike a main target of the target assembly.

The high voltage electrical module includes a transformer.

Also includes a magnetic field generator; the magnetic field generator is used for generating a magnetic field from the outer side of the vacuum tube to penetrate through the vacuum tube so as to influence the focus position of electrons emitted by the filament emitter on the main target of the target assembly finally.

The focalizer is a focusing lens.

The auxiliary targets of the target assembly are multiple, and the thickness of the auxiliary target close to the main target is larger than that of the auxiliary target far away from the main target.

By adopting the technical scheme, the utility model discloses following beneficial effect has: (1) the utility model discloses the electron that the focuser made the filament transmitter send is gathered together and is formed X ray on the main target of target subassembly, and X ray can directly arouse secondary fluorescence locally through vice target, and energy conversion is high, can keep higher luminous flux, need not high power input and just can realize high light, can realize the formation of microfocus, and energy conversion is high to make the volume and the power of bulb can be very little, the application scene of simplifying greatly.

(2) The utility model discloses a focuser makes the miniaturization of effective focus and focus, can effectively reduce the interference and the ghost image of image, the reinforcing image definition, increase the SNR, make on the bulb can be applied to microscope and closely form images, owing to adopt the filament transmitter, the diameter of filament itself is less, the electric current is less than 2 milliamperes usually, can effectively reduce the service power, reduce the bulb volume, after focusing through the focuser simultaneously, the vast majority of electron beam is transmitted to the target subassembly on, make electron availability factor higher, and the local main target of target subassembly, the design of vice target, the light efficiency can effectively improve again

(3) The utility model discloses a it has insulating material to fill between the casing of vacuum tube and the ceramic tube, avoids the electric leakage.

(4) The utility model discloses a still establish on the vacuum tube outer wall including the cover, shield unnecessary radiation and restraint target subassembly radiation angle's radiation protection shield cover can effectively shield useless radiation to and restrain the radiation angle of the secondary fluorescence that generates. And the light-emitting angle of the secondary fluorescence can be adjusted from a narrow angle of 10 degrees to a wide angle of 80 degrees, so that the distance required by detection is greatly reduced.

(5) The utility model discloses a high-tension electricity module includes the transformer, and the transformer is through adjusting the high pressure, adjusts the electron energy that the filament transmitter struck the target subassembly to control X ray photon energy scope, the high pressure can be adjusted at 1KV ~ 120 KV.

(6) The utility model discloses still include magnetic field generator, further influence the trend of electron through magnetic field generator to adjust the light-emitting frequency spectrum, and help the heated region of dispersion target subassembly, prolong the life of target.

Drawings

In order that the present invention may be more readily and clearly understood, the following detailed description of the present invention is given in conjunction with the accompanying drawings, in which

Fig. 1 is a schematic view of non-local target detection.

Fig. 2 is a schematic diagram of local target detection.

Fig. 3 is a schematic diagram of energy conversion of a conventional kurgiz bulb.

Fig. 4 is a schematic structural diagram of the present invention.

FIG. 5 is a schematic diagram of imaging a point light source and a line light source.

Fig. 6 is a spatial distribution diagram of energy of the main target of the present invention.

Fig. 7 is a schematic diagram of energy transfer after the target material is hit by electrons according to the present invention.

The reference numbers in the drawings are:

the device comprises a vacuum tube 1, a ceramic tube 1-1, a shell 1-2, a filament emitter 2, a focalizer 3, a target assembly 4, a main target 4-1, an auxiliary target 4-2, a radiation-proof shielding cover 5, a constraint part 5-1, a high-voltage electric module 6 and a magnetic field generator 7.

Detailed Description

(example 1)

Referring to fig. 4, the local secondary fluorescent radiation X-ray tube of the present embodiment is characterized in that: the method comprises the following steps:

a vacuum tube 1.

And the filament emitter 2 is arranged in the vacuum tube 1 and used for emitting electrons.

And the focalizer 3 is arranged in the vacuum tube 1 and is used for gathering the electrons emitted by the filament emitter 2 into an electron beam.

The target assembly 4 is arranged on the vacuum tube 1 and comprises a main target 4-1 and an auxiliary target 4-2 which are sequentially arranged along the emission direction of the electron beam, and the thickness of the main target 4-1 is smaller than that of the auxiliary target 4-2. The electron beam produces a small or divergent focus on the main target 4-1.

The vacuum tube 1 comprises a ceramic tube 1-1 and a housing 1-2. The housing 1-2 is used to enclose the ceramic tube 1-1. The filament emitter 2 and the focuser 3 are both arranged in the ceramic tube 1-1. The target assembly 4 is disposed at one end of the housing 1-2, and the target assembly 4 is aligned with the filament emitter 2.

An insulating material is filled between the shell 1-2 of the vacuum tube 1 and the ceramic tube 1-1.

The local secondary fluorescent radiation X-ray tube of the embodiment further comprises an anti-radiation shielding cover 5 which is sleeved on the outer wall of the vacuum tube 1 and used for shielding redundant radiation and restraining the radiation angle of the target component 4.

One end of the radiation protection shield 5 close to the target assembly 4 is provided with a constraint part 5-1 for constraining the radiation angle of the target. The constraint part 5-1 is annular, and the target assembly 4 is positioned at the axis of the constraint part 5-1. The inner diameter of the restriction portion 5-1 is gradually increased from the inside to the outside.

The local secondary fluorescent radiation X-ray tube of the embodiment also comprises a high-voltage electric module 6 arranged between the ceramic tube 1-1 and the shell 1-2 of the vacuum tube 1. The target assembly 4, the filament emitter 2 and the focuser 3 are respectively electrically connected with the high-voltage electric module 6, and the target assembly 4 and the filament emitter 2 form a potential difference.

The focuser 3 applies a voltage to electrons emitted from the filament emitter 2 to confine the electrons in a narrow traveling angle, thereby forming an electron beam and causing the electron beam to strike the main target 4-1 of the target assembly 4. The focuser 3 can effectively reduce the focal point. Note that different applications are required by different focus sizes. For example, a small focal spot may not be needed for a wide range of biological treatments, and a wide range of light source emissions, such as panoramic imaging, may not be needed. However, many applications desire a smaller focus, especially for microscopy and close range imaging, which avoids edge ghosting and noise from folded imaging of different light sources. The relative size relationship of the imaging focus and the object can make the imaging result greatly different from reality. The image of a point object generated by a line light source (similar to a large focus) is identical to the image of a long object generated by a point light source (similar to a small focus), and thus erroneous judgment may occur (see fig. 5).

The conventional large X-ray machine generates an X-ray spot having a diameter of 300 μm, which results in an imaging distance of about one meter. With proper focusing, the local secondary fluorescent radiation X-ray tube of the present embodiment can produce a focus as low as about 50 microns for close range imaging. For microscope applications, even finer adjustments can be made lower.

The diameter of the filament emitter 2 is small and the current is typically below 2 milliamps. However, since the most electron beam electrons are transferred to the main target 4-1 after focusing, the electron use efficiency can be kept high. And by the design of the secondary target 4-2 of secondary local fluorescence, the light efficiency is improved greatly compared with the traditional method. This results in the secondary fluorescence emitted being much more efficient than X-ray conventional curio tube rays, increasing useful brightness. And the conventional X-ray tube often uses a single filter, which is equivalent to generating a plurality of emission points while filtering light, so that the imaging effect and the luminous efficacy are much lower. In a scenario of X-rays used to image tissue, thicker tissue requires higher energy X-rays; the high energy efficiency makes the device small in size and power, greatly simplifying the application scenarios, such as simple CT and portable mobile imaging become possible, and is not limited to dental examinations with low light requirements.

As the focuser 3 miniaturizes the effective focus and focus, image disturbance and ghosting problems are reduced, and in addition to enhancing image sharpness, the signal-to-noise ratio is further increased so that the required brightness and dose are further reduced. The image definition can be greatly helpful for non-destructive testing requiring high definition, such as circuit, medicine and specimen. While low doses are closely related to the health and safety of human imaging.

By proper parameter selection, the generated high-quality secondary fluorescence can be applied to phase difference imaging by utilizing the single energy spectrum correlation characteristic of the secondary fluorescence. The phase difference imaging greatly reduces the requirement and even dependence on a monochromator, simultaneously can avoid the difficulty requirement of reducing the grid for coherent imaging, and also avoids the dependence on a large synchronous generator to a certain extent.

The high voltage electrical module 6 includes a transformer.

A magnetic field generator 7 is also included. The magnetic field generator 7 is used for generating a magnetic field from the outside of the vacuum tube 1 to penetrate through the vacuum tube 1 so as to influence the final focus position of electrons emitted by the filament emitter 2 on the main target 4-1 of the target assembly 4.

The focuser 3 is a focusing mirror.

The secondary targets 4-2 of the target assembly 4 are provided in plurality, and the overall thickness of the secondary target 4-2 close to the primary target 4-1 is larger than that of the secondary target 4-2 far from the primary target 4-1.

In addition, the emission light with fluorescence as the main component can be selected on the characteristics of light intensity and light spectral line. If the target is chosen thicker, the high energy radiation is converted more into secondary fluorescence, resulting in a purer spectral characteristic closer to that of mono-energetic light, but the luminous efficacy is reduced because more energy is blocked and converted into heat. When the thickness of the main target 4-1 and the sub-target 4-2 of the target assembly 4 is larger, the high-energy radiation is more converted into secondary fluorescence, and the purer spectral characteristics are closer to single-energy light, but the luminous efficiency is reduced, because more energy is blocked and converted into heat, and when the overall thickness of the main target 4-1 and the sub-target 4-2 of the target assembly 4 is smaller, more light penetrates, including higher energy and lower energy besides fluorescence. In a portable scene, the requirement of high brightness is more important, and on the premise that high power and heat dissipation in a fixed scene are not problems, pure fluorescence is more beneficial to imaging quality and dosage reduction, so that the overall thickness of the main target 4-1 and the auxiliary target 4-2 can be selected according to the application scene.

The principle of the local secondary fluorescent radiation X-ray tube of the embodiment is as follows: electrons are emitted from the filament emitter 2, more than 90% of the electrons are focused by the focuser 3 through voltage and are converged on the main target 4-1, the electron use efficiency is greatly improved, and after the main target 4-1 is hit by the electrons, the emitted energy is divided into Bremsstrahlung and characteristic spectral lines, as shown in FIG. 6. Because the energy and the speed of the electrons are very high, the energy of the X-ray acted by the electrons simultaneously has a forward tilting type, so that the X-ray continuously propagates to the main target 4-1 to reach the auxiliary target 4-2 in a deep way, the K absorption edge of the auxiliary target 4-2 can be selected to be lower than or even equal to the main target 4-1, so that the X-ray of a high-energy part can be continuously absorbed to carry out the conversion of local secondary fluorescence, meanwhile, the auxiliary target 4-2 can also effectively absorb the energy lower than the K absorption edge part of the auxiliary target, most of the energy in a medical image is absorbed by a human body to be useless for imaging, finally, the X-ray is mainly based on the secondary fluorescence, and a small amount of high-energy and low-energy Bremsstrahlung rays which are not completely converted are accompanied by the local generation of the above processes, less energy is wasted in the form of heat, and both Bremsstrahlung and fluorescent rays are not subjected to ineffective attenuation in the form of shielding or long-, so that a high luminous flux can be maintained. The spectral characteristics of the final light output can also be adjusted for the energy of the electron beam by the target thickness and the choice of material metal, so that results optimized for the application are obtained.

As the electrons enter the main target 4-1 and decelerate by inelastic coulomb scattering, they lose energy in multiple steps. The first 200nm are both electron dependent and do not produce X-rays, and between 200nm and 2um the Bremsstrahlung radiation and characteristic lines are generated sequentially as shown in figure 7. The interaction of coulombs with target nuclei can be Bremsstrahlung emission or fluorescence when the electron energy is above the K absorption edge of the target element. Bremsstrahlung radiation has a forward bias with the most likely energy distribution of about 2/3 for electron beam energy. In order to allow this portion of the energy to resonate, the electron energy is at least 50% higher than the K-absorption edge. The mechanisms of radiation and secondary radiation are different in the energy generation of electrons, which can only excite X-rays at the target surface, but local secondary rays are generated by photons. The penetration force is stronger, and the directivity is more open. The thickness of the sub-target 4-2 determines the generation of such light. The thermal loading on the end window of the sub-target 4-2 still produces a number of non-X-ray generated scatterings and auger emissions, but these constitute only a small part of the total energy loading of the electron beam, the vast majority of which is still realized in the form of local fluorescence. Because of the high energy efficiency, the bulb tube can emit high light without high power, thereby further reducing the requirements of focusing and heat dissipation, and realizing the generation of micro-focus.

In contrast to Bremsstrahlung radiation produced by electron impact, secondary fluorescence has the further advantage that it no longer has a forward tilt, but converts to a uniform omnidirectional. The heel effect of the traditional Kurqi bulb is eliminated, and the imaging process is not provided with direction specificity any more and is greatly simplified; and the brightness is uniformly distributed in the spherical space and can be prejudged, and the post-processing and correction of the image are simpler. Meanwhile, because the angle of the spherical light is large, the spherical light can be adjusted to a proper angle according to requirements through the restraint device, the spherical light is not limited to a narrow angle of the traditional library curio, and the imaging detection distance of objects with the same size can be greatly reduced. Because the attenuation multiple of light and the distance form a square relation, the reduction of the imaging distance reduces the requirement of light output quantity, reduces the power requirement and the manufacturing cost of equipment, and provides a foundation for mobile application; and secondly, the radiation to the environment is greatly reduced, so that the method is suitable for emergency scenes and areas with underdeveloped infrastructures and the like, wherein the radiation shielding is not easy to implement.

The local secondary fluorescent radiation X-ray tube of the embodiment has various applications: such as medical digital radiography, CT imaging, mammography, angiography, cardiovascular imaging, bone densitometry imaging, dental imaging, circuit board imaging, radiation therapy, and X-ray imaging using integrated circuits for radiography, fluoroscopy, and tomography. Computed tomography and multi-energy X-ray techniques may use the present techniques to obtain images; can also be arranged in a C-shaped arm for intraoperative real-time monitoring; non-destructive evaluation of objects including luggage and shipping containers, or checking integrated circuits and circuit boards may also be applied; and general X-ray fluoroscopy for non-destructive testing applications, which can be used to treat diseases by killing or altering biological samples.

Such as digital radiographic imaging, high light and small size may make portable X-ray and even hand-held instruments possible. Meanwhile, the vertical small-sized wide-angle cone scanning is possible, the load is reduced, the mechanical bearing requirement is greatly reduced, and the cost of the simple CT can be greatly reduced. And effectively reduce the radiation dose and quickly obtain large-area imaging.

Meanwhile, the energy bandwidth of fluorescence is narrow, so that proper energy can be easily selected to appropriately penetrate through a measured object, and meanwhile, the detection plate can correspond to the measured object more sensitively. Therefore, only low effective light is needed to achieve the purpose of imaging, and the radiation dose of the patient can be reduced without influencing the image.

The above-mentioned embodiments, further detailed description of the objects, technical solutions and advantages of the present invention, it should be understood that the above-mentioned embodiments are only specific embodiments of the present invention, and are not intended to limit the present invention, and any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (9)

1. A local secondary fluorescent radiation X-ray tube is characterized in that: the method comprises the following steps:

a vacuum tube (1);

the filament emitter (2) is arranged in the vacuum tube (1) and used for emitting electrons;

the focalizer (3) is arranged in the vacuum tube (1) and is used for gathering electrons emitted by the filament emitter (2) into an electron beam;

the target assembly (4) is arranged on the vacuum tube (1) and comprises a main target (4-1) and an auxiliary target (4-2) which are sequentially arranged along the emission direction of the electron beam, and the thickness of the main target (4-1) is smaller than that of the auxiliary target (4-2); the electron beam generates a small or divergent focus on the main target (4-1).

2. The local secondary fluorescent radiation X-ray tube of claim 1, wherein: the vacuum tube (1) comprises a ceramic tube (1-1) and a shell (1-2); the shell (1-2) is used for sealing the ceramic tube (1-1); the filament emitter (2) and the focalizer (3) are both arranged in the ceramic tube (1-1); the target assembly (4) is arranged at one end of the shell (1-2), and the target assembly (4) is aligned with the filament emitter (2).

3. The local secondary fluorescent radiation X-ray tube of claim 2, wherein: and an insulating material is filled between the shell (1-2) of the vacuum tube (1) and the ceramic tube (1-1).

4. The local secondary fluorescent radiation X-ray tube of claim 1, wherein: the anti-radiation target assembly is characterized by further comprising an anti-radiation shielding cover (5) which is sleeved on the outer wall of the vacuum tube (1) and used for shielding redundant radiation and restraining the radiation angle of the target assembly (4).

5. The local secondary fluorescent radiation X-ray tube of claim 4, wherein: one end of the radiation-proof shielding cover (5) close to the target assembly (4) is provided with a restraining part (5-1) for restraining the radiation angle of the target; the constraint part (5-1) is annular, and the target assembly (4) is positioned at the axis of the constraint part (5-1); the inner diameter of the restriction part (5-1) is gradually increased from the inside to the outside.

6. The local secondary fluorescent radiation X-ray tube of claim 2, wherein: the high-voltage electric module (6) is arranged between the ceramic tube (1-1) of the vacuum tube (1) and the shell (1-2); the target assembly (4), the filament emitter (2) and the focalizer (3) are respectively electrically connected with the high-voltage electric module (6), and the target assembly (4) and the filament emitter (2) form potential difference.

7. The local secondary fluorescent radiation X-ray tube of claim 6, wherein: the focuser (3) presses the electrons released by the filament emitter (2) through voltage to limit the electrons in a narrow walking angle, so as to form an electron beam, and the electron beam strikes a main target (4-1) of the target assembly (4).

8. The local secondary fluorescent radiation X-ray tube of claim 1, wherein: further comprising a magnetic field generator (7); the magnetic field generator (7) is used for generating a magnetic field from the outer side of the vacuum tube (1) to penetrate through the vacuum tube (1) to influence the focus position of electrons emitted by the filament emitter (2) on a main target (4-1) of the target assembly (4).

9. The local secondary fluorescent radiation X-ray tube of claim 1, wherein: the focalizer (3) is a focusing lens.

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