A carbon nanotube cathode ion source device and neutron tube

Abstract

This invention discloses a carbon nanotube cathode ion source device and a neutron tube. The carbon nanotube cathode assembly is disposed at one end of a support pillar, with several protrusions at the end of the assembly furthest from the pillar. A first insulator is fitted onto the outside of the carbon nanotube cathode assembly, and a grid cylinder is fitted onto the outside of the first insulator. Through holes corresponding to the protrusions are formed on the end face of the grid cylinder near the carbon nanotube cathode assembly. A second insulator is fitted onto the outside of the grid cylinder, and a fixing assembly is fitted onto the outside of the support pillar. One end of the fixing assembly abuts against one end of the cathode, the first insulator, the grid cylinder, and the second insulator. An anode cylinder is fitted onto the outside of the second insulator and the fixing assembly. This invention provides a compact ion source structure and improves the degassing temperature, achieving a larger ion current output. It overcomes the disadvantages of complex structures and low degassing temperatures associated with magnetic material components, while also improving the output ion current and enhancing the stability of the ion source operation.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of well logging, and relates to a carbon nanotube cathode ion source device and a neutron tube. BACKGROUND

[0002] The existing neutron tube ion source generally includes a cold cathode (or hot cathode) Penning ion source, a radio frequency ion source, a microwave ion source and an arc discharge ion source, and most of them are Penning ion sources. The Penning ion source has a magnetic material structure, and the magnetic field generated by the magnetic material structure and the electric field generated by the anode cylinder and the cathode jointly act on the gas molecules and atoms in a certain pressure range to ionize the gas molecules and atoms to form the required ions. The existence of the magnetic material limits the outgassing of the high-temperature material of the ion source, and also makes the structure of the ion source relatively complex and the stability of the ion source is affected.

[0003] The radio frequency ion source and the microwave ion source have excellent performance, but their structures are complex, they have more auxiliary structures, and it is difficult to miniaturize them, so they are rarely used in the structure of the neutron tube. The arc discharge ion source is a special ion source for a pulse type neutron tube. SUMMARY

[0004] The present application aims to solve the problems of the existing ion source device, such as complex structure, poor stability, limitation of outgassing of the high-temperature material of the ion source, and inability to adapt to miniaturized neutron tubes, and to provide a carbon nanotube cathode ion source device and a neutron tube.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] A carbon nanotube cathode ion source device, comprising a grid cylinder, an anode cylinder, a carbon nanotube cathode assembly, a first insulator, a second insulator, a fixing assembly and a support;

[0007] The carbon nanotube cathode assembly is arranged at one end of the support, and a plurality of protrusions are arranged at the end of the carbon nanotube cathode assembly away from the support;

[0008] The first insulator is sleeved on the outer side of the carbon nanotube cathode assembly, the grid cylinder is sleeved on the outer side of the first insulator, and a through hole corresponding to the protrusion is formed in the end face of the grid cylinder close to the carbon nanotube cathode assembly;

[0009] The second insulator is sleeved on the outer side of the grid cylinder, and the fixing assembly is sleeved on the outer side of the support. One end of the fixing assembly abuts against one end of the cathode, the first insulator, the grid cylinder and the second insulator;

[0010] The anode cylinder is sleeved on the outer sides of the second insulator and the fixing assembly.

[0011] Further improvements of the present application are as follows:

[0012] The carbon nanotube cathode assembly comprises a carbon nanotube material coating and a cathode;

[0013] The cathode is arranged at one end of the support, and the cathode is axially provided with a plurality of convex points and a carbon nanotube material coating on the end surface away from the support.

[0014] The end surface of the cathode provided with the convex points is spaced apart from the end surface of the grid cylinder provided with the through holes.

[0015] One end of the cathode is provided with a groove, and one end of the support is inlaid in the cathode groove.

[0016] A thread is arranged in the groove of the cathode, and the support is rigidly connected with the cathode through the thread.

[0017] The first insulator is an isolation ceramic, and the isolation ceramic is sleeved on the outside of the cathode assembly.

[0018] The second insulator is an anode ceramic, and the anode ceramic is sleeved on the outside of the cathode.

[0019] The fixing assembly comprises a compression fixing ring and a welding ring.

[0020] The compression fixing ring is sleeved on the outside of the support, the welding ring is sleeved on the outside of the compression fixing ring, and the compression fixing ring is axially provided with a lead wire through hole.

[0021] One end of the compression fixing ring is abutted against the end surface close to the cathode, the first insulator and the grid cylinder, and one end of the welding ring is abutted against the end surface close to the anode ceramic.

[0022] The compression fixing ring is made of ceramic material.

[0023] A neutron tube comprises a neutron tube housing and an ion source device.

[0024] The ion source device is arranged inside the neutron tube housing, and the ion source device is the ion source device according to any one of claims 1-8.

[0025] The further improvement of the neutron tube is that:

[0026] The neutron tube housing is made of ceramic material.

[0027] Compared with the prior art, the present application has the following beneficial effects:

[0028] The application discloses a carbon nanotube cathode ion source device, which is characterized in that a carbon nanotube cathode assembly is arranged in the inside of an anode cylinder, the anode cylinder is sleeved outside the cathode assembly, an electric field is formed between the cathode assembly and the anode cylinder, a higher electron flow density can be obtained at a lower opening voltage, a higher plasma density can be obtained without a magnetic field, the structural complexity and low gas removal temperature caused by the magnetic material structure are overcome, the ion flow output by the ion source is improved, the stability of the ion source is enhanced, a plurality of convex points are arranged at one end of the carbon nanotube cathode assembly, a plurality of through holes corresponding to the convex points are arranged on the end face of the grid cylinder, a regular local extremely high electric field distribution is formed between the cathode and the grid cylinder, a high-density field electron emission can be generated at a lower grid cylinder voltage, the ion source structure is compact, the gas removal temperature is improved, the ion source can be applied to a small neutron tube, the working reliability is improved, and a larger ion flow output can be obtained.

[0029] Further, a plurality of convex points are arranged on the end face of the cathode, the size of the convex points and the size of the through holes corresponding to the grid cylinder can be adjusted, different electric field distributions are generated, and a higher electron passing rate is obtained.

[0030] Further, a gap exists between the end face of the cathode provided with the convex points and the end face of the grid cylinder provided with the through holes, the size of the gap is adjusted, a specific electric field distribution is formed, and a higher electron flow emission is obtained. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some of the embodiments of the application, and therefore should not be regarded as a limitation to the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0032] Figure 1 The figure is a structural schematic diagram of the application.

[0033] In the figure, 1 is a carbon nanotube material plating layer, 2 is a grid cylinder, 3 is an anode cylinder, 4 is a cathode, 5 is an isolation ceramic, 6 is an anode ceramic, 7 is a compression fixing ring, 8 is a welding ring, 9 is a support column, and 10 is a neutron tube shell. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the embodiments of the application more clear, the following will combine the drawings in the embodiments of the application to clearly and completely describe the technical solutions in the embodiments of the application. Obviously, the described embodiments are some of the embodiments of the application, rather than all the embodiments. The components of the embodiments of the application described and shown in the drawings can be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the application provided in the drawings is not intended to limit the scope of the claimed application, but merely represent selected embodiments of the application. Based upon the embodiments of the application, all other embodiments that would be obvious to one of ordinary skill in the art based upon the present application are intended to be within the scope of the present application.

[0036] It should be noted that similar reference numbers and characters represent similar items in the drawings, and therefore, once an item is defined in one drawing, it need not be further defined and explained in subsequent drawings.

[0037] In the description of the embodiments of the present application, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate the orientation or position relationship based on the orientation or position relationship shown in the drawings, or the orientation or position relationship when the product of the application is usually placed, and are only for the convenience of describing the application and simplifying the description, and therefore cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application. In addition, the terms "first", "second", etc. are only used for differentiation and cannot be understood as indicating or implying relative importance.

[0038] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly inclined. For example, "horizontal" only means that its direction is relatively more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0039] In the description of the embodiments of the present application, it should also be noted that unless otherwise explicitly specified and limited, if the terms "arrangement", "installation", "connection", "connection" appear, they should be understood in a broad sense, for example, they can be fixedly connected, or detachably connected, or integrally connected; can be mechanically connected, or electrically connected; can be directly connected, or indirectly connected through an intermediate medium; can be the communication inside two elements. For those of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0040] The present application will be described in further detail below with reference to the accompanying drawings:

[0041] Referring to Figure 1 The embodiment of the present application discloses a carbon nanotube cathode ion source device, which comprises a carbon nanotube material plating layer 1, a grid cylinder 2, an anode cylinder 3, a cathode 4, an isolation ceramic 5, an anode ceramic 6, a compression fixing ring 7, a welding ring 8, a support 9 and a neutron tube shell 10.

[0042] An embodiment is disclosed, a cathode 4 is arranged at one end of a support 9, a groove is arranged at the end of the support 9 connected with the cathode 4, and the support 9 is embedded in the groove; a plurality of groups of convex points are arranged at the other end surface of the cathode 4, and a carbon nanotube material plating layer 1 is arranged at the same time, the carbon nanotube material plating layer 1 covers the convex points and the end surface where the convex points are located. The carbon nanotube material is used as a field electron emission cathode, has the advantages of low turn-on voltage and large electron emission density, so that the ion source has the characteristics of low power consumption, high ion flow output intensity, simple and reliable structure, and is more suitable for small neutron tubes.

[0043] The isolation ceramic 5 is arranged outside the cathode 4, the grid cylinder 2 is arranged outside the isolation ceramic 5, the through holes corresponding to the convex points are arranged on the end surface of the grid cylinder 2 close to the cathode 4, there is a gap between the end surface of the grid cylinder 2 where the through holes are arranged and the end surface of the cathode 4 where the convex points are arranged, and a certain electric field distribution is formed between the two end surfaces, wherein the shape of the convex points is cylindrical, the convex points are distributed in a wheel shape on the end surface of the cathode 4, and by appropriately adjusting the size of the convex points, the size of the through holes on the grid cylinder 2 and the distance between the two end surfaces of the grid cylinder 2 and the cathode 4, a specific electric field can be formed to adjust the emission density and pass rate of the field electrons. The embodiment of the application can obtain a higher electron flow density at a lower turn-on voltage, and a higher plasma density is also obtained without the need for a magnetic field, which not only overcomes the disadvantages of complex structure and low material outgassing temperature caused by magnetic material structural parts, but also improves the ion source output ion flow and enhances the stability of the ion source work.

[0044] The anode ceramic 6 is arranged outside the front end of the cathode 4, and the anode ceramic 6 can insulate and isolate the anode cylinder 3 and the grid cylinder 2

[0045] In the embodiment, the ends of the grid cylinder 2, the isolation ceramic 5 and the anode ceramic 6 are flush, the cathode 4 is embedded in the interior of the grid cylinder 2, and the end of the grid cylinder 2 is provided with a metal lead wire.

[0046] The compression fixing ring 7 is arranged outside the support 9, one end of the compression fixing ring 7 is in abutment with the end surfaces of the cathode 4, the grid cylinder 2, the isolation ceramic 5 and the anode ceramic 6 close to each other at the same time, 4 lead wire through holes are arranged in the interior of the compression fixing ring 7 in the axial direction, the metal lead wire at the end of the grid cylinder 2 can be led out through any one of the lead wire through holes; the welding ring 8 is arranged outside the compression fixing ring 7, one end of the welding ring 8 is in abutment with the end surface of the anode ceramic 6, and the end of the welding ring 8 is flush with the end of the anode cylinder 3.

[0047] The compression fixing ring 7 disclosed in the embodiment is made of ceramic material.

[0048] In the embodiment, a thread is arranged in the groove of the cathode 4, and the support 9 is connected with the cathode 4 through the thread.

[0049] The embodiment of the present application also discloses a neutron tube, which comprises a neutron tube shell 10 and the ion source device disclosed by the embodiment.

[0050] The embodiment of the present application also discloses an installation method.

[0051] Before the ion source assembly, the cathode 4 needs to be surface treated and high-temperature degassed, carbon nanotube material evaporation is carried out under a specific high-temperature-vacuum degree-time parameter combination condition, and a metal lead wire with a proper length is spot welded at the tail end of the grid cylinder 2.

[0052] The welding ring 8 and the compression fixing ring 7 are vacuum brazed to form a combination; the rest of the parts are cleaned and high-temperature degassed;

[0053] Firstly, the anode ceramic 6 is installed in the anode cylinder 3, then the grid cylinder 2 is installed in the inner cavity of the anode ceramic 6, then the isolation ceramic 5 is installed, then the cathode 4 is installed, and finally the combination of the welding ring 8 and the compression fixing ring 7 is installed, the metal lead wire at the tail end of the grid cylinder 2 passes through the wire hole of the combination, so as to be welded on the lead electrode during the neutron tube assembly, the assembled components are compressed and assembled, at this time, the welding ring 8 and the tail end of the anode cylinder 3 should be aligned, the argon arc welding process is carried out to encapsulate the assembled ion source into a whole, and finally the support 9 is connected in the threaded hole at the tail end of the cathode 4 of the ion source to complete the ion source assembly.

[0054] The embodiment of the present application designs a special carbon nanotube material plated cathode, the end surface of the cathode is designed with a wheel-shaped distribution of small circular convex point arrays, corresponding to a similarly wheel-shaped distribution of hole array grids, a regular local extremely high electric field distribution is formed between the cathode and the grid, high-density field electron emission can be generated under a lower grid voltage, and a higher field electron emission and electron passing rate can be obtained by reasonably adjusting the grid hole size and the grid-cathode spacing. The electron obtains kinetic energy under the action of the anode high voltage, collides and ionizes with the working gas, so that the required working gas ions are generated, and the anode simultaneously serves as an output electrode, and the working gas ions are output from the anode hole under the joint action of the internal acceleration electric field of the neutron tube.

[0055] The above only describes the preferred embodiments of the present application and is not used to limit the present application, and the present application can have various changes and variations for those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A carbon nanotube cathode ion source apparatus, characterized by, It comprises a grid cylinder (2), an anode cylinder (3), a carbon nanotube cathode assembly, a first insulator, a second insulator, a fixing assembly and a support (9); The carbon nanotube cathode assembly is arranged at one end of the support (9), and the end of the carbon nanotube cathode assembly away from the support (9) is provided with a plurality of convex points; The first insulator is sleeved outside the carbon nanotube cathode assembly, the grid cylinder (2) is sleeved outside the first insulator, and a through hole corresponding to the convex point is formed in the end face of the grid cylinder (2) close to the carbon nanotube cathode assembly; The second insulator is sleeved outside the grid cylinder (2), and the fixing assembly is sleeved outside the support (9), and one end of the fixing assembly abuts against one end of the cathode (4), the first insulator, the grid cylinder (2) and the second insulator; The anode cylinder (3) is sleeved outside the second insulator and the fixing assembly.

2. The carbon nanotube cathode ion source device according to claim 1, wherein The carbon nanotube cathode assembly comprises a carbon nanotube material coating (1) and a cathode (4); The cathode (4) is arranged at one end of the support (9), and the end face of the cathode (4) away from the support (9) is axially provided with a plurality of convex points and a carbon nanotube material coating (1).

3. A carbon nanotube cathode ion source device according to claim 2, wherein There is a gap between the end face of the cathode (4) provided with the convex points and the end face of the grid cylinder (2) provided with the through hole.

4. The carbon nanotube cathode ion source apparatus according to claim 3, wherein One end of the cathode (4) is provided with a groove, and one end of the support (9) is embedded in the groove of the cathode (4).

5. A carbon nanotube cathode ion source device according to claim 4, wherein The groove of the cathode (4) is provided with a thread, and the support (9) is rigidly connected with the cathode (4) through the thread.

6. The carbon nanotube cathode ion source apparatus according to claim 1, wherein The first insulator is an isolation ceramic (5), and the isolation ceramic (5) is sleeved outside the cathode assembly; The second insulator is an anode ceramic (6), and the anode ceramic (6) is sleeved outside the cathode (4).

7. The carbon nanotube cathode ion source apparatus according to claim 1, wherein The fixing assembly comprises a compression fixing ring (7) and a welding ring (8); The compression fixing ring (7) is sleeved outside the support (9), the welding ring (8) is sleeved outside the compression fixing ring (7), and the compression fixing ring (7) is axially provided with a lead wire through hole; One end of the compression fixing ring (7) abuts against the end face close to the cathode (4), the first insulator and the grid cylinder (2); and one end of the welding ring (8) abuts against the end face close to the anode ceramic (6).

8. A carbon nanotube cathode ion source device according to claim 7, wherein The compression fixing ring (7) is made of ceramic material.

9. A neutron tube based on the carbon nanotube cathode ion source device according to any one of claims 1 to 8, characterized in that It comprises a neutron tube shell (10) and an ion source device; The ion source device is arranged inside the neutron tube shell (10), and the ion source device is the ion source device according to any one of claims 1-8.

10. A neutron tube according to claim 9, characterized in that The neutron tube shell (10) is made of ceramic material.

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