Superhigh-yield gaseous target neutron tube and installation method thereof

Abstract

The invention discloses an ultrahigh-yield gaseous target neutron tube and an installation method thereof in the technical field of neutron tubes, and the neutron tube comprises a shell, a heating excitation assembly, an acceleration assembly and a target receiving assembly, the heating excitation assembly is installed at the lower end of the shell, and the acceleration assembly is located in the shell; the input end of the acceleration assembly corresponds to the output end of the heating excitation assembly, and the target receiving assembly is installed at the upper end of the shell. According to the invention, the acceleration electrode is arranged to be in the conical table shape, the size of the inlet of the acceleration electrode is increased, the length of the acceleration electrode is shortened, and a proper acceleration electric field can be formed; a grid mesh output hole structure is adopted, and the aperture ratio of a grid mesh framework is adjusted, so that the ion transmittance is the maximum value, and a relatively large ion current can be obtained; by arranging the improved grid mesh and the improved acceleration pole, a large amount of neutrons are output, so that the yield of the super-high-yield gaseous target neutron tube can reach more than 1 * 1010n / s, and the problem that the neutron yield of an existing neutron tube is relatively low is solved.

Description

Technical Field

[0001] The invention relates to the technical field of neutron tubes, in particular to an ultra-high-yield gaseous target neutron tube and an installation method thereof. Background Art

[0002] Neutron tube is an instrument that can emit neutron flux. It uses high-energy particles to hit the target nucleus, or the instantaneous high temperature generated by the laser to cause the hydrogen isotopes deuterium and tritium in the vacuum tube to produce instantaneous neutron flux pulses, and uses the strong penetrating power of neutron flux. Neutron tubes have been widely used in oil well logging, irradiated shrimp, irradiated fish farming, nuclear physics scientific research and teaching experiments.

[0003] At present, the output of neutron tubes used or researched in the market is basically concentrated in 1.5×10 8 n / s level, for example, a high-yield self-forming target DD neutron tube and its manufacturing method with publication number CN113543448A, which mainly includes a tube shell assembly, a core column assembly, a gas pressure regulating assembly, a Penning ion source assembly, an accelerating electrode and a self-forming target assembly; the gas pressure regulating assembly is heated by electricity to release a certain amount of deuterium gas, and the Penning ion source assembly ionizes the deuterium gas to generate deuterium ions, which are accelerated by the accelerating electrode and bombard the self-forming target surface to emit fast neutrons, and the DD neutron yield reaches 1×10 7 n / s or more.

[0004] Although the DD neutron yield of the above neutron tube can reach 1×10 7 However, with the development of neutron photography and non-destructive technology, there is an urgent need for neutron tubes with higher yields, and the neutron yield of existing neutron tubes cannot meet the use requirements.

[0005] Based on this, the present invention designs an ultra-high-yield gaseous target neutron tube and an installation method thereof to solve the above problems. Summary of the invention

[0006] The purpose of the present invention is to provide a super high yield gaseous target neutron tube and its installation method to solve the problems raised in the above background technology, so that the yield of the neutron tube can reach 1×10 10 n / s.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] An ultra-high-yield gaseous target neutron tube comprises a shell, a heating and excitation component, an acceleration component and a target receiving component, wherein the heating and excitation component is installed at the lower end of the shell and extends upward to the inside of the shell, the acceleration component is located inside the shell, and the input end of the acceleration component corresponds to the output end of the heating and excitation component, and the target receiving component is installed at the upper end of the shell, and the output end of the acceleration component corresponds to the target receiving component, so that the excited ions located in the heating and excitation component are accelerated by the acceleration component and reach the target receiving component;

[0009] The heating and excitation component includes a sealing unit, a storage unit and an ion unit. The sealing unit is installed at the bottom of the housing and is used to seal the bottom end of the housing. The storage unit is installed in the sealing unit and is connected to the ion unit. The storage unit is used to store the medium, and the ion unit is used to ionize and excite the medium, and release gas into the ion unit through the storage unit.

[0010] The ion unit comprises a cylindrical ion source cover, which is located inside the housing, the output end of the storage is connected to the input end of the ion source cover, and the ion source chassis, rear cathode, anode structure, front cathode, magnetic steel ring and grid are arranged inside the ion source cover from bottom to top.

[0011] A second through hole is arranged on the upper end surface of the ion source cover, a third through hole corresponding to the second through hole is arranged on the magnetic steel ring, and the grid is located between the second through hole and the third through hole;

[0012] The target receiving assembly includes a target, a target substrate, a target bottom magnet and an upper sealing film. The target is made of a graphene film, and a sealed cavity is provided at the bottom of the target substrate corresponding to the position of the target. A thin tube is connected to the sealed cavity, and the thin tube extends out of the shell to the external environment.

[0013] Preferably, the accelerating assembly includes a conical accelerating electrode, and the output end diameter of the accelerating electrode is larger than the input end diameter, a fourth through hole is provided at the input end of the accelerating electrode, and the fourth through hole corresponds to the position of the second through hole at the output end of the heating excitation assembly, the output end of the accelerating electrode is connected to the inner wall of the outer shell, and is correspondingly connected to the input end of the target receiving assembly.

[0014] Preferably, the target receiving assembly includes a target, a target substrate, a target bottom magnetic steel and an upper end sealing ferrule, and the output end of the accelerating electrode corresponds to the position of the lower end surface of the target;

[0015] The lower end of the upper sealing kovar is connected to the upper end of the shell, and is used to seal the upper end of the shell. The target substrate is installed in the upper sealing kovar. The target is set on the lower surface of the target substrate, and the axial cross-section of the lower end surface of the target is in an arc shape. The target bottom magnetic steel is installed between the target substrate and the upper sealing kovar, and is used to form a magnetic field at the lower end of the target, so that ions move toward the direction of the target bottom magnetic steel through the magnetic field to bombard the target surface.

[0016] The upper end surface of the target base is provided with an external magnetic steel ring structure, and the lower end side wall of the external magnetic steel ring structure is connected to the inner surface of the target base magnetic steel, and the upper end passes through the upper end sealing valve to extend to the upper end outside of the shell.

[0017] Preferably, the sealing unit comprises a lower end sealing valve and an exhaust pipe, the diameter of the lower end sealing valve is equal to the diameter of the shell, and the lower end sealing valve is connected to the lower end of the shell;

[0018] A stem disc is installed in the lower end sealing valve, and a reservoir is installed on the upper end surface of the stem disc. One end of the exhaust pipe passes through the stem disc and is connected to the reservoir, and the other end extends out of the shell and is connected to the external environment for conveying the medium into the reservoir.

[0019] The storage device is connected to an external power supply device through a metal wire.

[0020] Preferably, the heating excitation component also includes a magnetic steel structure, and the magnetic steel structure includes a magnetic steel cover and a magnetic steel sleeve, a magnetic conductive sheet and a magnetic steel column arranged in the magnetic steel cover from bottom to top, a first through hole is provided on the magnetic conductive sheet, and the first through hole is used to install the magnetic steel outside the tube, the top end of the magnetic steel cover is in contact with the rear cathode, and the lower end of the magnetic steel cover is arranged on the core column disk.

[0021] Preferably, the anode structure comprises a large anode magnetic ring, an anode and a small anode magnetic ring, the large anode magnetic ring and the small anode magnetic ring are both connected to the inner wall of the ion source cover, one end of the large anode magnetic ring is connected to the rear cathode, the other end is connected to one end of the small anode magnetic ring, the other end of the small anode magnetic ring is connected to the front cathode, and the anode is connected to the inner walls of the large anode magnetic ring and the small anode magnetic ring respectively;

[0022] The anode is connected to an external power source through a lead.

[0023] Preferably, the skeleton aperture ratio of the grid is D / d=4.0, wherein D is the side length of the small square holes of the grid, and d is the skeleton width between the small square holes.

[0024] Preferably, the diameter of the accelerating electrode entrance is 16-19 mm, and the diameter of the target 13 is 42-47 mm.

[0025] Preferably, the diameter of the accelerating electrode entrance is 18 mm, the diameter of the target 13 is 45 mm, and the outer dimensions of the ultra-high yield neutron tube are Φ65 mm×320 mm.

[0026] A method for installing an ultra-high-yield gaseous target neutron tube comprises the following steps:

[0027] S1, install the grid into the upper end of the ion source cover and fit it with the second through hole;

[0028] S2. Install the magnetic steel ring into the ion source cover so that the upper surface of the magnetic steel ring and the lower surface of the grid fit together;

[0029] S3, sequentially install the front cathode, the small anode magnetic ring, the anode and the large anode magnetic ring with the same diameter as the small anode magnetic ring into the ion source cover, and the front cathode contacts the lower surface of the magnetic steel ring;

[0030] S4, the anode is connected to the inner wall of the small anode magnetic ring and the large anode magnetic ring, so that the anode is fixed;

[0031] S5, welding a nickel wire or a stainless steel wire to the anode to form an anode lead, and passing the anode lead through the housing for connection with an external power source;

[0032] S6, aligning the upper end of the ion source cover with the upper end of the ion source cover chassis and then connecting them;

[0033] S7, installing the reservoir on the sealing unit;

[0034] S8, connecting the sealing unit to the lower end of the housing so that the output end of the storage corresponds to the input port on the ion source cover chassis, and connecting the target receiving assembly to the upper end of the housing so that the neutron tube is formed;

[0035] S9, high temperature degassing, placing the formed neutron tube in an environment at least above 450°C for one hour for high temperature degassing.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1. The target in the present invention adopts a graphene film, and a sealed cavity and a thin tube are set at the bottom of the target substrate, thereby improving the structure of the target receiving component, and adopting a gas-titanium target neutron tube to change the tritium-titanium target into gas-tritium, thereby increasing the probability of nuclear reaction;

[0038] 2. The present invention adopts a grid output hole structure and adjusts the grid skeleton aperture ratio to maximize the ion transmittance, thereby obtaining a larger ion flow. By setting an improved grid and an improved accelerating electrode, a large amount of neutron output is achieved, so that the yield of the ultra-high-yield gaseous target neutron tube of the present invention can reach 1×10 10 n / s or more;

[0039] 4. The target structure of the present invention adopts an external magnetic steel ring structure, which forms a magnetic field of sufficient strength on the target surface while maximizing the heat dissipation area of ​​the target base and reducing the local high temperature problem caused by the large target power;

[0040] 5. The present invention simplifies the structure of the shell and the corresponding sealing member, thereby enhancing the vacuum sealing strength and the electrical insulation strength of the ceramic shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0042] Figure 1 It is a schematic diagram of the structure of the present invention;

[0043] Figure 2 It is a schematic diagram of the structure of the upper end sealing caving of the present invention;

[0044] Figure 3 It is a structural schematic diagram of the ion source cover of the present invention;

[0045] Figure 4 This is a schematic diagram of the structure of the lower end sealing cutter of the present invention;

[0046] Figure 5 It is a schematic diagram of the structure of the grid of the present invention.

[0047] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0048] 1-lower end sealed Kovar, 2-lead, 3-magnetic steel sleeve, 4-ceramic tube, 5-magnetic conductive sheet, 6-magnetic steel column, 7-large anode magnetic ring, 8-anode, 9-small anode magnetic ring, 10-grid, 11-housing, 12-accelerating pole, 13-target, 14-sealed chamber, 15-exhaust pipe, 16-sealing ring, 17-core column disk, 18-storage, 19-ion source chassis, 20-ion source cover, 21-rear cathode, 22-front cathode, 23-magnetic steel ring, 24-target base, 25-target base magnet, 26-upper end sealed Kovar, 27-thin tube. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0050] Embodiment 1

[0051] Please refer to the accompanying drawings, the present invention provides a technical solution:

[0052] An ultra-high yield gaseous target neutron tube, such as Figure 1As shown, it includes a hollow cylindrical ceramic shell 11, a heating and excitation component, an acceleration component and a target receiving component. The heating and excitation component is installed at the lower end of the shell 11 and extends to the inside of the shell 11. The acceleration component is located inside the shell 11, and the input end of the acceleration component corresponds to the output end of the heating and excitation component. The target receiving component is installed at the upper end of the shell 11; wherein the heating and excitation component is used to heat the gas stored in the neutron tube to form ions, which are accelerated by the acceleration component, so that the neutrons finally reach the target receiving component.

[0053] The heating and excitation assembly includes a sealing unit for sealing the bottom end of the outer shell 11, a storage 18 for storing a medium, and an ion unit for ionizing and exciting ions to form neutrons. The sealing unit is installed at the lower end of the outer shell 11, the lower end of the ion unit is connected to the sealing unit, the upper end of the ion unit extends to the inside of the outer shell 11 and corresponds to the lower end of the acceleration assembly, and the upper end of the acceleration assembly corresponds to the target receiving assembly, so that the neutrons emitted by the ion unit reach the target receiving assembly after being accelerated by the acceleration assembly.

[0054] The sealing unit includes a cylindrical lower sealing valve 1 with a diameter equal to that of the outer shell 11, a lead 2, a magnetic steel structure and an exhaust pipe 15. The lower sealing valve 1 is connected to the lower end of the outer shell 11, and a core column disk 17 is installed on the lower sealing valve 1. The outer diameter of the core column disk 17 matches the inner diameter of the lower sealing valve 1, and a sealing ring 16 is arranged between the core column disk 17 and the inner surface of the lower sealing valve 1 for sealing.

[0055] A storage 18 is provided on the upper end surface of the core disc 17 , so that the storage 18 is located inside the housing 11 and is used for storing gaseous medium and regulating the gas pressure inside the neutron tube.

[0056] One end of the exhaust pipe 15 passes through the core disc 17 and is connected to the storage tank 18, and the other end of the exhaust pipe 15 is connected to the external environment, which is used to transport the gas medium into the storage tank 18. The air inside the shell 11 can also be transported to the external environment to confirm whether the exhaust pipe has the function of transporting the gas medium.

[0057] The metal wire inside the housing 11 is connected to the reservoir 18, so that the reservoir 18 is connected to an external power source through the metal wire.

[0058] The ion unit includes a cylindrical ion source cover 20, which is arranged in the housing 11. The ion source cover 20 is provided with an ion source chassis 19, a rear cathode 21, an anode structure, a front cathode 22, a magnetic steel ring 23 and a grid 10 which are connected in sequence from bottom to top.

[0059] The lower end of the magnetic steel structure is mounted on the core plate 17 , and the upper end extends toward the inside of the housing 11 , and finally passes through the ion source bottom plate 19 to be connected to the rear cathode 21 .

[0060] The anode structure includes a large anode magnetic ring 7, an anode 8 and a small anode magnetic ring 9. The large anode magnetic ring 7 and the small anode magnetic ring 9 are both connected to the inner wall of the ion source cover 20. One end of the large anode magnetic ring 7 is connected to the rear cathode 21, and the other end is connected to one end of the small anode magnetic ring 9. The other end of the small anode magnetic ring 9 is connected to the front cathode 22. The anode 8 is connected to the inner walls of the large anode magnetic ring 7 and the small anode magnetic ring 9 respectively.

[0061] The stem disc 17 is provided with a lead wire 2, which is connected to an external power source and the anode 8 inside the housing 11. The lead wire 2 includes a cathode wire, an anode wire and a ground terminal.

[0062] The magnetic steel structure includes a magnetic steel cover and a magnetic steel sleeve 3, a magnetic conductive sheet 5 and a magnetic steel column 6 which are connected and arranged in sequence in the magnetic steel cover. A first through hole is provided on the magnetic conductive sheet 5, and the first through hole is used to install the outer magnetic steel of the tube. The upper end of the magnetic steel cover is in contact with the rear cathode 21, and the lower end of the magnetic steel cover is arranged on the core column disk 17.

[0063] A second through hole is formed on the upper end surface of the ion source cover 20, and a third through hole corresponding to the second through hole is formed on the magnetic steel ring 23, and the grid 10 is located between the second through hole and the third through hole.

[0064] In order to obtain a larger ion flow, a grid output hole structure is used while avoiding the influence of the accelerating electric field on the ion source, and the grid skeleton aperture ratio is adjusted to maximize the ion transmittance. When the skeleton aperture ratio of the grid 10 D / d = 4.0, Figure 5 As shown, D is the side length of the small square holes of the grid 10, d is the skeleton width between the square holes, and the maximum ion permeability is 65%.

[0065] A ceramic tube 4 is provided in the ion source cover 20 , and the anode 8 is connected to the lead 2 via a metal wire passing through the ceramic tube 4 , and the ceramic tube 4 is used for insulation.

[0066] The accelerating assembly includes a conical accelerating pole 12, the lower end of which is provided with a fourth through hole corresponding to the third through hole, the upper end of which is connected to the inner wall of the housing 11, and the diameter of the upper end of the accelerating pole 12 is greater than that of the lower end.

[0067] The target receiving assembly includes a target 13, a target base 24, a target base magnet 25 and an upper sealing kovar 26; the lower end of the upper sealing kovar 26 is connected to the upper end of the housing 11, the target base 24 is installed in the upper sealing kovar 26, and a connecting ring for sealing is provided between the target base 24 and the upper sealing kovar 26, the target 13 is provided on the lower surface of the target base 24, and the axial cross-section of the lower end face of the target 13 is an arc shape; the upper end of the accelerating pole 12 corresponds to the target 13.

[0068] The target bottom magnet 25 is installed at the upper end of the target base 24 to form an axial magnetic field at the lower end of the target 13 , so that the neutrons released by the accelerating pole 12 move toward the target bottom magnet 25 and finally bombard the target surface of the target 13 .

[0069] The target 13 is made of graphene film, and a sealed cavity 14 is provided at the bottom of the target substrate 24 corresponding to the position of the target 13, and a thin tube 27 is connected to the sealed cavity 14, and the thin tube 27 extends out of the outer shell 11 to the external environment, thereby using a gas-titanium target neutron tube to convert the tritium titanium target into gas-tritium, increasing the probability of nuclear reaction, and using a new material graphene film.

[0070] In this embodiment, in order to form a suitable accelerating electric field and avoid sputtering contamination that may be formed on the inner wall of the accelerating gap ceramic shell, a conical accelerating electrode 12 is used, and the diameter of the lower end entrance of the accelerating electrode 12 is increased from Φ8mm to Φ18mm, thereby shortening the accelerating electrode length and increasing the size of the target 13, so that the radius of the target 13 is increased from Φ38mm to Φ45mm, and at the same time, the overall length of the neutron tube is shortened, so that the specification of the neutron tube is Φ65×320mm.

[0071] The present invention realizes a large amount of neutron output by providing an improved grid 10 and an improved accelerating electrode 12, so that the yield of the ultra-high-yield gaseous target neutron tube of the present invention can reach 1×10 10 n / s or more.

[0072] There is a correlation between the size of the target 13 and the length of the accelerating gap and the aperture of the entrance of the accelerating electrode 12. When the length of the accelerating gap is determined, the size of the spot formed on the target surface of the target 13 by the neutrons output by the accelerating electrode 12 is positively correlated with the aperture of the entrance of the accelerating electrode 12, but it is nonlinear.

[0073] The accelerating electrode gap length refers to the distance from the upper end surface of the ion source cover 20 to the entrance of the accelerating electrode 12 .

[0074] The aperture of the outlet of the accelerating electrode 12 is matched with the diameter of the housing 11 and can be installed normally.

[0075] An external magnetic steel ring structure is installed on the upper end surface of the target substrate 24, and the external magnetic steel ring structure extends to the outer upper end of the outer shell 11 through the upper end sealing valve 26. The external magnetic steel ring structure can form a magnetic field of sufficient strength on the target surface while maximizing the heat dissipation area of ​​the target substrate 24 and reducing the local high temperature problem caused by the large target power.

[0076] The installation method of the neutron tube is as follows:

[0077] Step 1: install the grid 10 into the upper end of the ion source cover 20 and fit it with the second through hole.

[0078] Step 2, install the magnetic steel ring 23 into the upper end of the grid 10, so that the magnetic steel ring 23 and the grid 10 are attached together.

[0079] Step 3, sequentially install the front cathode 22, the small anode magnetic ring 9, the anode 8 and the large anode magnetic ring 7 with the same diameter as the small anode magnetic ring 9 into the ion source cover 20.

[0080] Step 4: the anode 8 is connected to the inner wall of the small anode magnetic ring 9 and the large anode magnetic ring 7, so that the anode 8 is fixed.

[0081] Step 5, use a Φ0.8mm nickel wire or stainless steel wire to weld on the anode 8 to form an anode lead, pass the anode lead through the ceramic tube 4, connect with the lead 2 and fix it by spot welding.

[0082] Step 6: align the upper end of the ion source cover 20 with the upper end of the ion source cover chassis 19, and spot weld three evenly distributed points using argon arc welding.

[0083] Step 7: Connect the sealing unit to the lower end of the housing 11, and connect the target receiving assembly to the upper end of the housing 11, so that the neutron tube is formed.

[0084] Step 8: Pass the lead wire 2 through the lower end of the housing 11 and connect it to the ground.

[0085] Step 9, high temperature degassing, the formed neutron tube is placed in an environment of 450°C for one hour for high temperature degassing.

[0086] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0087] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. An ultra-high-yield gaseous target neutron tube, comprising a housing (11), a heating and excitation assembly, an accelerating assembly and a target receiving assembly, wherein the heating and excitation assembly is mounted at the lower end of the housing (11) and extends upward to the interior of the housing (11), the accelerating assembly is located inside the housing (11), and the input end of the accelerating assembly corresponds to the output end of the heating and excitation assembly, and the target receiving assembly is mounted at the upper end of the housing (11), and the output end of the accelerating assembly corresponds to the target receiving assembly, characterized in that: The heating excitation component comprises a sealing unit, a storage device and an ion unit, wherein the sealing unit is installed at the bottom of the housing (11), and the storage device (18) is installed in the sealing unit and is in communication with the ion unit; The ion unit comprises a cylindrical ion source cover (20), the ion source cover (20) is located inside the housing (11), the output end of the storage (18) is connected to the input end of the ion source cover (20), and the ion source cover (20) is provided with an ion source chassis (19), a rear cathode (21), an anode structure, a front cathode (22), a magnetic steel ring (23) and a grid (10) connected in sequence from bottom to top; A second through hole is provided on the upper end surface of the ion source cover (20), a third through hole corresponding to the second through hole is provided on the magnetic steel ring (23), and the grid (10) is located between the second through hole and the third through hole; The target receiving assembly comprises a target (13), a target substrate (24), a target bottom magnetic steel (25) and an upper end sealing kovar (26); the target (13) is made of a graphene film, and a sealed cavity (14) is provided at the bottom of the target substrate (24) corresponding to the position of the target (13); a thin tube (27) is connected to the sealed cavity (14), and the thin tube (27) extends out of the housing (11) to the external environment.

2. The ultra-high-yield gaseous target neutron tube according to claim 1, characterized in that: The accelerating component comprises a conical table-shaped accelerating electrode (12), the output end of the accelerating electrode (12) corresponds to the lower end surface position of the target (13), and the output end diameter of the accelerating electrode (12) is larger than the input end diameter, the input end of the accelerating electrode (12) is provided with a fourth through hole, and the fourth through hole corresponds to the position of the second through hole at the output end of the heating excitation component, the output end of the accelerating electrode (12) is connected to the inner wall of the housing (11), and is correspondingly connected to the input end of the target receiving component.

3. The ultra-high-yield gaseous target neutron tube according to claim 1, characterized in that: The lower end of the upper sealing kovar (26) is connected to the upper end of the housing (11), the target base (24) is installed in the upper sealing kovar (26), the target (13) is arranged on the lower surface of the target base (24), and the axial cross section of the lower end surface of the target (13) is in the shape of an arc, and the target base magnetic steel (25) is installed between the target base (24) and the upper sealing kovar (26); The upper end surface of the target base (24) is provided with an external magnetic steel ring structure, and the lower end side wall of the external magnetic steel ring structure is connected to the inner surface of the target base magnetic steel (25), and the upper end passes through the upper end sealing valve (26) to extend to the outside of the upper end of the shell (11).

4. The ultra-high-yield gaseous target neutron tube according to claim 1, characterized in that: The sealing unit comprises a lower end sealing kovar (1) and an exhaust pipe (15), the diameter of the lower end sealing kovar (1) is equal to the diameter of the outer shell (11), and the lower end sealing kovar (1) is connected to the lower end of the outer shell (11); A stem disc (17) is installed in the lower end sealing kovar (1), a reservoir (18) is installed on the upper end surface of the stem disc (17), one end of the exhaust pipe (15) passes through the stem disc (17) and is connected to the reservoir (18), and the other end extends out of the housing (11) and is connected to the external environment; The storage device (18) is connected to an external power supply device via a metal wire.

5. The ultra-high-yield gaseous target neutron tube according to claim 4, characterized in that: The heating excitation component also includes a magnetic steel structure, and the magnetic steel structure includes a magnetic steel cover and a magnetic steel sleeve (3), a magnetic conductive sheet (5) and a magnetic steel column (6) arranged in the magnetic steel cover from bottom to top, wherein a first through hole is arranged on the magnetic conductive sheet (5), and the first through hole is used to install the magnetic steel outside the tube, the top end of the magnetic steel cover is in contact with the rear cathode (21), and the lower end of the magnetic steel cover is arranged on the core column disk (17).

6. The ultra-high-yield gaseous target neutron tube according to claim 1, characterized in that: The anode structure comprises a large anode magnetic ring (7), an anode (8) and a small anode magnetic ring (9); the large anode magnetic ring (7) and the small anode magnetic ring (9) are both connected to the inner wall of an ion source cover (20); one end of the large anode magnetic ring (7) is connected to a rear cathode (21), and the other end is connected to one end of the small anode magnetic ring (9); the other end of the small anode magnetic ring (9) is connected to a front cathode (22); and the anode (8) is respectively connected to the inner walls of the large anode magnetic ring (7) and the small anode magnetic ring (9); The anode (8) is connected to an external power source via a lead wire (2).

7. The ultra-high-yield gaseous target neutron tube according to claim 1, characterized in that: The skeleton aperture ratio of the grid (10) is D / d=4.0, wherein D is the side length of the small square holes of the grid (10), and d is the skeleton width between the small square holes.

8. The ultra-high-yield gaseous target neutron tube according to claim 2, characterized in that: The diameter of the entrance of the accelerating electrode (12) is 16-19 mm, and the diameter of the target (13) is 42-47 mm.

9. The ultra-high-yield gaseous target neutron tube according to claim 8, characterized in that: The diameter of the entrance of the accelerating electrode (12) is 18 mm, the diameter of the target (13) is 45 mm, and the outer dimensions of the ultra-high-yield neutron tube are Φ65 mm×320 mm.

10. A method for installing an ultra-high-yield gaseous target neutron tube as claimed in claim 1, characterized in that: The following steps are involved: S1, installing the grid (10) into the upper end of the ion source cover (20) so that it fits the second through hole; S2, installing the magnetic steel ring (23) into the interior of the ion source cover (20) so that the upper surface of the magnetic steel ring (23) and the lower surface of the grid (10) are in contact with each other; S3, sequentially loading the front cathode (22), the small anode magnetic ring (9), the anode (8), and the large anode magnetic ring (7) having the same diameter as the small anode magnetic ring (9) into the ion source cover (20), the front cathode (22) being in contact with the lower surface of the magnetic steel ring (23); S4, the anode (8) is connected to the inner wall of the small anode magnetic ring (9) and the large anode magnetic ring (7), so that the anode (8) is fixed; S5, welding a nickel wire or a stainless steel wire to the anode (8) to form an anode lead, and passing the anode lead through the housing (11) for connection with an external power source; S6, aligning the upper end of the ion source cover (20) with the upper end of the ion source cover chassis (19) and connecting them; S7, installing the reservoir (18) on the sealing unit; S8, connecting the sealing unit to the lower end of the housing (11) so that the output end of the storage (18) corresponds to the input port on the ion source cover chassis (19), and connecting the target receiving assembly to the upper end of the housing (11) so that the neutron tube is formed; S9, high temperature degassing, placing the formed neutron tube in an environment at least above 450°C for one hour for high temperature degassing.

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