A high flux X-ray source

Abstract

The present invention relates to a high flux X-ray source. The device comprises: an electron beam emitting device, an electron focusing ring and a composite anode arranged in sequence from top to bottom; the composite anode comprises an anode target material, a diamond sheet and a substrate in sequence from top to bottom; the electron beam emitted by the electron beam emitting device passes through the electron focusing ring to reach the anode target material of the composite anode. The present invention can quickly dissipate the high heat generated by the electron beam to prevent the anode from melting at high temperature due to heat accumulation.

Description

Technical Field

[0001] The present invention relates to the technical field of X-ray sources, and in particular to a high-flux X-ray source. Background Art

[0002] According to the working principle of the current X-ray source, the process of high-energy electrons bombarding the anode is complex, in which the conversion efficiency of the excited X-rays is very low (about 1%), and most of it is converted into heat energy. In order to indirectly increase the flux of emitted X-rays, it is necessary to increase the number of electrons emitted by the cathode of the X-ray source and improve the thermal performance of the anode. First, since the increase in the number of electrons means that the electron beam density received per unit area of ​​the anode increases, the increase in the electron beam density of the cathode of the X-ray source is the increase in the tube current; secondly, since the focal spot size of the X-ray source is limited, the heat generated by the high-density electron beam is very high and is concentrated in the focal spot area, so this places high demands on the thermal performance of the anode, including the heat capacity and thermal conductivity of the material.

[0003] The tube current of X-ray sources produced by existing technology is generally about 1-5mA, and the tube current of some imported high-flux sources is about 30-50mA. It can be seen that a larger tube current can effectively increase the outgoing X-ray flux, reduce the detection exposure time, and improve the detection efficiency, but according to the current emission mode of the X-ray cathode, the outgoing X-ray emission flux cannot be further increased. Even if the tube current is increased, the currently commonly used anode cannot directly withstand the heat of high heat flux density, resulting in the melting of the anode. Summary of the invention

[0004] The purpose of the present invention is to provide a high flux X-ray source, which can quickly dissipate the high heat generated by the electron beam to prevent the anode from melting at high temperature due to heat accumulation.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] A high flux X-ray source comprises: an electron beam emitting device, an electron focusing ring and a composite anode which are arranged in sequence from top to bottom; the composite anode comprises an anode target material, a diamond sheet and a substrate in sequence from top to bottom; the electron beam emitted by the electron beam emitting device passes through the electron focusing ring and reaches the anode target material of the composite anode.

[0007] Optionally, the electron beam emitting device comprises: a cathode structure and an electron beam multiplying structure arranged in sequence from top to bottom, and the electron beam emitted by the cathode structure passes through the electron beam multiplying structure.

[0008] Optionally, the cathode structure includes: a cathode cover, a cathode, a first fixed electrode and a second fixed electrode; the cathode is arranged inside the cathode cover, and the first fixed electrode passes through the cathode cover and is connected to the cathode; the second fixed electrode is connected to the cathode cover.

[0009] Optionally, the cathode structure further includes: a ceramic base fixed on the cathode cover, and the first fixed electrode passes through the ceramic base and is connected to the cathode.

[0010] Optionally, the electron beam multiplication structure includes: a third fixed electrode, a fourth fixed electrode, and arranged in sequence from top to bottom: a first electrode ring, a microchannel plate, and a second electrode ring; the first electrode ring is connected to the third fixed electrode, the fourth fixed electrode is connected to the second electrode ring, and the electron beam emitted by the cathode structure passes through the inner ring of the first electrode ring, the microchannel plate, and the inner ring of the second electrode ring in sequence.

[0011] Optionally, the electron beam multiplication structure further includes: an insulating pressure sheet ring and a microchannel plate fixing sleeve; the second electrode ring is arranged on the insulating pressure sheet ring, and the first electrode ring, the microchannel plate, the second electrode ring and the insulating pressure sheet ring are all fixedly arranged in the microchannel plate fixing sleeve.

[0012] Optionally, the composite anode further includes: solder, the solder is disposed at the connection between the diamond sheet and the substrate, and the solder is used to connect the diamond sheet and the substrate.

[0013] Optionally, a groove is provided on the upper surface of the substrate, and the diamond sheet is arranged in the groove.

[0014] Optionally, the anode target is made of metal tungsten.

[0015] Optionally, the microchannel plate fixing sleeve is a hollow cylinder without a bottom surface; the top surface of the microchannel plate fixing sleeve is a circular ring structure, and the electron beam emitted by the cathode structure passes through the inner ring of the top surface, the inner ring of the first electrode ring, the microchannel plate, the inner ring of the second electrode ring and the inner ring of the insulating pressing ring in sequence.

[0016] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects: the high-flux X-ray source of the present invention comprises: an electron beam emitting device, an electron focusing ring and a composite anode arranged in sequence from top to bottom; the composite anode comprises an anode target material, a diamond sheet and a substrate in sequence from top to bottom; the electron beam emitted by the electron beam emitting device passes through the electron focusing ring to reach the anode target material of the composite anode, and by adopting the composite anode and utilizing the fast axial heat transfer rate characteristic of diamond, rapid heat conduction is generated in the axial direction between the materials, and the heat flow is expanded in the radial direction, thereby reducing the heat flux density per unit area, thereby improving the heat dissipation capacity of the anode of the X-ray source. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0018] Figure 1 A side cross-sectional view of a high flux X-ray source provided by an embodiment of the present invention;

[0019] Figure 2 A side cross-sectional view of an electron beam emitting device provided by an embodiment of the present invention;

[0020] Figure 3 A front view of a cathode structure provided by an embodiment of the present invention;

[0021] Figure 4 A bottom view of a cathode structure provided by an embodiment of the present invention;

[0022] Figure 5 A bottom view of an electron beam multiplication structure provided by an embodiment of the present invention;

[0023] Figure 6 A side cross-sectional view of an electron beam multiplication structure provided by an embodiment of the present invention;

[0024] Figure 7 A partial enlarged view of a composite anode provided in an embodiment of the present invention;

[0025] Figure 8 A schematic diagram of the general structure of a high-flux X-ray source provided by an embodiment of the present invention.

[0026] Explanation of symbols:

[0027] I-high flux X-ray source, II-electron beam emitting device, 1-quartz housing, 2-1-first fixed electrode, 2-2-second fixed electrode, 2-3-third fixed electrode, 2-4-fourth fixed electrode, 3-electron focusing ring, 4-composite anode, 5-high voltage connecting hole, 6-cathode structure, 7-electron beam multiplication structure, 8-cathode cover, 9-ceramic base, 10-cathode, 11-microchannel plate fixing sleeve, 12-insulating pressing ring, 12-1-pit, 13-1-first electrode ring, 13-2-second electrode ring, 14-microchannel plate, 15-anode target, 16-diamond sheet, 17-solder, 18-copper column. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] like Figure 1 and Figure 8 As shown, the embodiment of the present invention provides a high flux X-ray source I, comprising: an electron beam emitting device II, an electron focusing ring 3 and a composite anode 4 arranged in order from top to bottom; Figure 7 As shown, the composite anode 4 includes an anode target 15 , a diamond sheet 16 and a substrate from top to bottom; the electron beam emitted by the electron beam emitting device II passes through the electron focusing ring 3 to reach the anode target 15 of the composite anode 4 .

[0031] As an optional implementation, the electron beam emitting device II, the electron focusing ring 3 and the composite anode 4 are packaged in a quartz housing 1, and the positions of the three devices are fixed and positioned by external electrodes.

[0032] As an optional implementation, Figure 2 As shown, the electron beam emitting device II comprises: a cathode structure 6 and an electron beam multiplying structure 7 which are arranged in sequence from top to bottom. The electron beam emitted by the cathode structure 6 passes through the electron beam multiplying structure 7 .

[0033] As an optional implementation, Figure 3 and Figure 4As shown, the cathode structure 6 includes: a cathode cover 8, a cathode 10, a first fixed electrode 2-1 and a second fixed electrode 2-2; the cathode 10 is arranged inside the cathode cover 8, and the first fixed electrode 2-1 passes through the cathode cover 8 and is connected to the cathode 10; the second fixed electrode 2-2 is connected to the cathode cover 8, and the first fixed electrode 2-1 and the second fixed electrode 2-2 penetrate the quartz shell 1 to connect to an external power supply.

[0034] As an optional embodiment, the cathode structure 6 further includes: a ceramic base 9 fixed on the cathode cover 8, and the first fixed electrode 2-1 passes through the ceramic base 9 and is connected to the cathode 10. Figure 3 As shown, specifically, the first fixed electrode 2-1 passes through the quartz shell 1 and the ceramic base 9 of the X-ray source, and is connected to the ceramic base 9 to form a whole. The ceramic base 9 is placed inside the cathode cover 8 and is pin-connected to the cathode cover 8 to form a whole. The cathode 10 is arranged below the ceramic base 9. The second fixed electrode 2-2 passes through the quartz shell 1 of the X-ray source package and is welded to the cathode cover 8 to form a whole.

[0035] As an optional implementation, the cathode 10 is a solenoid structure with a certain length, with the head and tail ends extended to a certain length, and connected to the first fixed electrode 2-1 by pressing.

[0036] As an optional implementation, Figure 5 and Figure 6 As shown, the electron beam multiplication structure 7 includes: a third fixed electrode 2-3, a fourth fixed electrode 2-4 and arranged in sequence from top to bottom: a first electrode ring 13-1, a microchannel plate 14 and a second electrode ring 13-2; the first electrode ring 13-1 is connected to the third fixed electrode 2-3, the fourth fixed electrode 2-4 is connected to the second electrode ring 13-2, the electron beam emitted by the cathode structure 6 passes through the inner ring of the first electrode ring 13-1, the microchannel plate 14 and the inner ring of the second electrode ring 13-2 in sequence, and the third fixed electrode 2-3 and the fourth fixed electrode 2-4 penetrate the quartz shell 1 to connect to the external power supply.

[0037] As an optional implementation, the electron beam multiplication structure 7 further includes: an insulating pressure piece ring 12 and a microchannel plate fixing sleeve 11; the second electrode ring 13-2 is arranged on the insulating pressure piece ring 12, and the first electrode ring 13-1, the microchannel plate 14, the second electrode ring 13-2 and the insulating pressure piece ring 12 are all fixedly arranged in the microchannel plate fixing sleeve 11. Specifically, as Figure 5 and Figure 6As shown, the electron beam multiplication structure 7 includes a microchannel plate fixing sleeve 11, an insulating pressing sheet arranged inside the microchannel plate fixing sleeve 11, a second electrode ring 13-2 arranged inside the microchannel plate fixing sleeve 11 and located above the insulating pressing sheet ring 12, a microchannel plate 14 arranged inside the microchannel plate fixing sleeve 11 and located above the second electrode ring 13-2, a first electrode ring 13-1 arranged inside the microchannel plate fixing sleeve 11 and located above the microchannel plate 14, and a third fixed electrode 2-3 passing through the microchannel plate fixing sleeve 11 and contacting the first electrode ring 13-1. and a fourth electrode ring 2-4 contacting the second electrode ring 13-2, the microchannel plate 14 is fixed by the first electrode ring 13-1 and the second electrode ring 13-2, the first electrode ring 13-1 and the second electrode ring 13-2 provide voltage to the microchannel plate 14 at the same time, the insulating pressing ring 12 is rotated and pressed by the concave point 12-1, and the first electrode ring 13-1, the second electrode ring 13-2 and the microchannel plate 14 are fixed inside the microchannel plate fixing sleeve 11, and the microchannel plate fixing sleeve 11 is in contact with the first electrode ring 13-1 and the second electrode ring 13-2 to form a whole.

[0038] As an optional embodiment, the electron focusing ring 3 is a copper metal ring of a certain thickness, the fifth fixed electrode 2-5 passes through the quartz housing 1 of the X-ray source package and is connected to the electron focusing ring 3 to form a whole, and the fifth fixed electrode 2-5 is connected to an external power supply system to provide voltage for the electron focusing ring 3. Through external power supply, the electron focusing ring 3 can form an electron lens structure with the first electrode ring 13-1, the second electrode ring 13-2, and the composite anode 4, the voltage value applied by the first electrode ring 13-1 and the second electrode ring 13-2 is V1, the voltage value applied by the electron focusing ring 3 is V2, and the voltage value applied by the composite anode 4 is V3, wherein the value of V2 is less than V1 and V3, so that a low-potential and adjustable electrostatic field region can be formed below the emission end of the high-flux electron beam emission structure and above the composite anode 4, which is used to converge the secondary emission electron beam to the focal area range specified on the surface of the anode target 15.

[0039] As an optional implementation, Figure 7 As shown, the composite anode 4 further includes: a solder 17, which is disposed at the connection between the diamond sheet 16 and the substrate, and is used to connect the diamond sheet 16 to the substrate.

[0040] As an optional implementation, a groove is provided on the upper surface of the substrate, and the diamond sheet 16 is provided in the groove, and the groove may be a circular groove.

[0041] As an optional embodiment, the substrate is a copper column 18, the upper surface of which is a wedge-shaped structure with an inclination angle of 10 to 20 degrees, and is encapsulated inside a quartz housing 1 encapsulated by an X-ray source. The lower surface of the substrate is a power supply end, which is used for fixing and high-voltage power supply, passes through the quartz housing 1 encapsulated by the X-ray source and is connected to an external power supply electrode through a high-voltage connection hole 5 arranged inside. The diamond sheet 16 is embedded in the groove of the copper column. After embedding, an anode target material is used to plate the surface of the diamond sheet and the entire copper column. The anode target material is attached to the upper surface of the diamond sheet and the substrate to form a thin film with a thickness of the micron level.

[0042] As an optional implementation, the anode target 15 is made of metal tungsten.

[0043] As an optional embodiment, the microchannel plate fixing sleeve 11 is a hollow cylinder without a bottom surface; the top surface of the microchannel plate fixing sleeve 11 is a circular ring structure, and the electron beam emitted by the cathode structure 6 passes through the inner ring of the top surface, the inner ring of the first electrode ring 13-1, the microchannel plate 14, the inner ring of the second electrode ring 13-2 and the inner ring of the insulating pressing ring 12 in sequence.

[0044] The present invention has the following technical effects:

[0045] The present invention relates to a source with relatively high X-ray emission flux, which is mainly used in an environment with high requirements on X-ray flux in an X-ray detection system.

[0046] The present invention utilizes the secondary multiplication effect of the microchannel plate to multiply the number of electrons emitted by the cathode, thereby probabilistically increasing the efficiency of the electron-excited anode to generate X-rays per unit time, and indirectly increasing the flux of emitted X-rays. At the same time, the composite anode used has a high thermal conductivity and heat load capacity, which can quickly dissipate the high heat generated by the electron beam and prevent high-temperature melting caused by heat accumulation.

[0047] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0048] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A high flux X-ray source, characterized in that: include: An electron beam emitting device, an electron focusing ring and a composite anode are sequentially arranged from top to bottom; the composite anode comprises an anode target material, a diamond sheet and a substrate sequentially from top to bottom; the electron beam emitted by the electron beam emitting device passes through the electron focusing ring and reaches the anode target material of the composite anode; The electron beam emitting device, electron focusing ring and composite anode are encapsulated in a quartz housing, and the positions of the three devices are fixed and positioned by external electrodes; The electron beam emitting device comprises: a cathode structure and an electron beam multiplying structure arranged in sequence from top to bottom, wherein the electron beam emitted by the cathode structure passes through the electron beam multiplying structure; The cathode structure comprises: a cathode cover, a cathode, a first fixed electrode and a second fixed electrode; the cathode is arranged inside the cathode cover, the first fixed electrode passes through the cathode cover and is connected to the cathode; the second fixed electrode is connected to the cathode cover, and the first fixed electrode and the second fixed electrode penetrate the quartz shell and are connected to an external power supply; The cathode structure further includes: a ceramic base fixed on the cathode cover, the first fixed electrode passes through the ceramic base and is connected to the cathode, specifically, the first fixed electrode passes through the quartz shell of the X-ray source and the ceramic base, and is connected to the ceramic base to form a whole, the ceramic base is arranged inside the cathode cover, and is connected to the cathode cover pin to form a whole, the cathode is arranged below the ceramic base, and the second fixed electrode passes through the quartz shell of the X-ray source package, and is welded to the cathode cover to form a whole; The cathode is a solenoid structure with a certain length, the head and tail ends of which are extended to a certain length and connected to the first fixed electrode by pressing; The electron beam multiplication structure comprises: a third fixed electrode, a fourth fixed electrode, and arranged in order from top to bottom: a first electrode ring, a microchannel plate, and a second electrode ring; the first electrode ring is connected to the third fixed electrode, the fourth fixed electrode is connected to the second electrode ring, the electron beam emitted by the cathode structure passes through the inner ring of the first electrode ring, the microchannel plate, and the inner ring of the second electrode ring in sequence, and the third fixed electrode and the fourth fixed electrode penetrate the quartz shell to connect to an external power supply; The electron beam multiplication structure also includes: an insulating pressure piece ring and a microchannel plate fixing sleeve; the second electrode ring is arranged on the insulating pressure piece ring, and the first electrode ring, the microchannel plate, the second electrode ring and the insulating pressure piece ring are all fixedly arranged in the microchannel plate fixing sleeve; the electron beam multiplication structure includes a microchannel plate fixing sleeve, an insulating pressure piece arranged inside the microchannel plate fixing sleeve, a second electrode ring arranged inside the microchannel plate fixing sleeve and located above the insulating pressure piece ring, a microchannel plate arranged inside the microchannel plate fixing sleeve and located above the second electrode ring, a first electrode ring arranged inside the microchannel plate fixing sleeve and located above the microchannel plate, a third fixed electrode passing through the microchannel plate fixing sleeve and contacting the first electrode ring, and a fourth electrode ring contacting the second electrode ring, the microchannel plate is fixed by the first electrode ring and the second electrode ring, the first electrode ring and the second electrode ring provide voltage to the microchannel plate at the same time, the insulating pressure piece ring is rotated and pressed by using the concave point to fix the first electrode ring, the second electrode ring and the microchannel plate inside the microchannel plate fixing sleeve, and the microchannel plate fixing sleeve contacts the first electrode ring and the second electrode ring to form a whole; The electron focusing ring is a copper metal ring of a certain thickness. The fifth fixed electrode passes through the quartz shell of the X-ray source package and is connected to the electron focusing ring to form a whole. The fifth fixed electrode is connected to an external power supply system to provide voltage for the electron focusing ring. Through external power supply, the electron focusing ring, the first electrode ring, the second electrode ring, and the composite anode form an electron lens structure. The voltage value applied by the first electrode ring and the second electrode ring is V1, the voltage value applied by the electron focusing ring is V2, and the voltage value applied by the composite anode is V3, wherein the value of V2 is smaller than V1 and V3, so that a low-potential and adjustable electrostatic field region is formed below the emission end of the high-flux electron beam emission structure and above the composite anode, which is used to converge the secondary emission electron beam to the focal area range specified on the surface of the anode target material. The composite anode further includes: a solder, the solder is arranged at the connection between the diamond sheet and the substrate, and the solder is used to connect the diamond sheet and the substrate; A groove is arranged on the upper surface of the substrate, the diamond sheet is arranged in the groove, and the groove is a circular groove; The substrate is a copper column, the upper surface of which is a wedge-shaped structure with an inclination angle of 10 to 20 degrees, and is packaged inside a quartz shell packaged with an X-ray source. The lower surface of the substrate is a power supply end, which is used for fixing and high-voltage power supply, passes through the quartz shell packaged with the X-ray source and is connected to an external power supply electrode through a high-voltage connection hole arranged inside. The diamond sheet is embedded in the groove of the copper column. After embedding, the surface of the diamond sheet and the copper column as a whole is plated with an anode target material, and the anode target material is attached to the upper surface of the diamond sheet and the substrate to form a film with a thickness of micrometers. The material of the anode target is metal tungsten; The microchannel plate fixing sleeve is a hollow cylinder without a bottom surface; the top surface of the microchannel plate fixing sleeve is a circular ring structure, and the electron beam emitted by the cathode structure passes through the inner ring of the top surface, the inner ring of the first electrode ring, the microchannel plate, the inner ring of the second electrode ring and the inner ring of the insulating pressing ring in sequence; By utilizing the secondary multiplication effect of the microchannel plate, the number of electrons emitted by the cathode is multiplied many times, thereby probabilistically increasing the efficiency of electrons exciting the anode to produce X-rays per unit time, and indirectly increasing the flux of emitted X-rays; at the same time, the composite anode used has high thermal conductivity and heat load capacity, which can quickly dissipate the high heat generated by the electron beam and prevent high-temperature melting caused by heat accumulation.

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