Super-high yield neutron tube and installation method thereof

Abstract

The invention relates to an ultra-high-yield neutron tube and an installation method thereof, which are used for solving the problem that the neutron yield of the existing neutron tube is relatively low. The device 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 extends upwards into the shell. The acceleration assembly is located in the shell, and the input end of the acceleration assembly corresponds to the output end of the heating excitation assembly; the target receiving assembly is installed at the upper end of the shell, and the output end of the acceleration assembly corresponds to the target receiving assembly. The target receiving assembly comprises a target, a target substrate, target bottom magnetic steel and an upper end sealing kovar; the lower end of the upper end sealing kovar is connected with the upper end of the shell; the target substrate is mounted in the upper-end sealed kovar, and the target is arranged on the front surface of the target substrate; the target bottom magnetic steel is mounted at the upper end of the target substrate, so that a magnetic field is formed at the lower end of the target, and ions bombard the target surface of the target through the magnetic field.

Description

Technical Field

[0001] The invention relates to a neutron tube, in particular to an ultra-high yield neutron tube and an installation method thereof. Background Art

[0002] At present, the output of neutron tubes used or researched in the market is basically concentrated in 1.5×10 8 For example, the Chinese invention patent with publication number CN 113543448 A discloses a high-yield self-target DD neutron tube and its manufacturing method. The DD neutron yield of the 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. Summary of the invention

[0003] The purpose of the present invention is to solve the problem of low neutron yield of existing neutron tubes, and propose an ultra-high yield neutron tube and an installation method thereof, the yield of which can reach 1×10 10 n / s or more.

[0004] To achieve the above object, the technical solution of the present invention is as follows:

[0005] An ultra-high-yield neutron tube comprises a shell, 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 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; 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;

[0006] Its special features are:

[0007] The heating and exciting assembly includes a sealing unit for sealing the lower end of the housing, a reservoir for storing the medium, and an ion unit for ionizing and exciting the medium;

[0008] The reservoir is installed in the sealing unit and communicated with the ion unit, and is used to release gas into the ion unit;

[0009] The ion unit includes a cylindrical ion source cover; the ion source cover is located inside the shell; the output end of the storage is connected to the input end of the ion source cover; the inside of the ion source cover is provided with an ion source chassis, a rear cathode, an anode structure, a front cathode, a magnetic steel ring and a grid connected in sequence from bottom to top; a second through hole is provided on the upper end surface of the ion source cover, the second through hole corresponds to a fourth through hole provided at the input end of the acceleration component and a third through hole provided on the magnetic steel ring, and the grid is located between the second through hole and the third through hole.

[0010] Furthermore, the accelerating component includes a conical accelerating electrode, the output end diameter of the accelerating electrode is larger than the input end diameter; the input end of the accelerating electrode is provided with a fourth through hole corresponding to the output end of the heating excitation component, the output end of the accelerating electrode is connected to the inner wall of the outer shell, and corresponds to the input end of the target receiving component.

[0011] Furthermore, the target receiving assembly includes a target, a target substrate, a target bottom magnetic steel and an upper end sealing kovar;

[0012] The output end of the accelerating electrode corresponds to the lower end surface of the target;

[0013] The lower end of the upper end sealing valve is connected to the upper end of the shell, and is used to seal the upper end of the shell;

[0014] The target substrate is installed in the upper sealing kovar, the target is arranged on the lower surface of the target substrate, and the axial cross section of the lower end surface of the target is in the shape of an arc; 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 target bottom magnetic steel through the magnetic field to bombard the target surface;

[0015] The upper end surface of the target substrate is provided with an external magnetic steel ring structure;

[0016] The lower end side wall of the external magnetic steel ring structure is connected to the inner surface of the target bottom magnetic steel, and the upper end passes through the upper end sealing valve and extends to the upper end outside of the casing.

[0017] Furthermore, 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.

[0018] Further, the sealing unit includes a lower end sealing valve and an exhaust pipe;

[0019] The diameter of the lower end sealing valve is equal to the diameter of the outer shell, and the lower end sealing valve is connected to the lower end of the outer shell;

[0020] A stem disc is installed in the lower end sealing valve, and the reservoir is installed on the upper end surface of the stem disc;

[0021] One end of the exhaust pipe passes through the stem plate and is connected to the reservoir, and the other end is connected to the external environment, so as to transport the medium into the reservoir;

[0022] The storage device is connected to an external power supply device through a metal wire.

[0023] Furthermore, the heating excitation component also includes a magnetic steel structure;

[0024] The magnetic steel structure comprises a magnetic steel sleeve, a magnetic conductive sheet and a magnetic steel column which are sequentially arranged in the magnetic steel cover from bottom to top. The top end of the magnetic steel cover is in contact with the rear cathode; the lower end of the magnetic steel cover is arranged on the core column disk.

[0025] Further, the anode structure includes 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;

[0026] The anode is connected to an external power source through a lead.

[0027] Furthermore, the diameter of the accelerating electrode entrance is 16-19 mm, and the diameter of the target is 42-47 mm.

[0028] Furthermore, the diameter of the accelerating electrode entrance is 18 mm, the diameter of the target is 45 mm, and the outer dimensions of the ultra-high-yield neutron tube are Φ65×320 mm.

[0029] A method for installing an ultra-high-yield neutron tube is special in that, based on the ultra-high-yield neutron tube described above, the installation steps are as follows:

[0030] Step 1: install the grid into the upper end of the ion source cover and fit it with the second through hole.

[0031] Step 2: 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.

[0032] Step 3, sequentially loading a front cathode, a small anode magnetic ring, an anode, and a large anode magnetic ring having the same diameter as the small anode magnetic ring into the ion source cover, wherein the front cathode contacts the lower surface of the magnetic steel ring;

[0033] Step 4, 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;

[0034] Step 5, 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 to be connected to an external power source;

[0035] Step 6, aligning the upper end of the ion source cover with the upper end of the ion source cover chassis and connecting them;

[0036] Step 7, installing the reservoir on the sealing unit;

[0037] Step 8, 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;

[0038] Step 9, high temperature degassing, placing the formed neutron tube in an environment at least above 450° C. for one hour for high temperature degassing.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] 1. In order to avoid the sputtering contamination that may be formed on the inner wall of the accelerating gap ceramic shell, the accelerating electrode adopts a conical shape and increases the size of the accelerating electrode entrance from Φ8 to Φ18 mm, thereby shortening the accelerating electrode length, resulting in an increase in the target size from Φ38 to Φ45 mm, and also shortening the neutron tube length.

[0041] 2. In order to obtain a larger ion flow, the present invention adopts a grid output hole structure while avoiding the influence of the accelerating electric field on the ion source, and adjusts the grid skeleton aperture ratio to maximize the ion transmittance.

[0042] 3. 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.

[0043] 4. In the present invention, the structure of the ceramic shell and the corresponding sealing valve is simplified, the vacuum sealing strength and the electrical insulation strength of the ceramic shell are enhanced, and the final outer dimensions of the sample tube are adjusted from the original design of Φ80×400 to Φ65×320mm.

[0044] 5. The present invention achieves a large output of neutrons by providing an improved grid and an improved accelerating electrode, so that the yield of the ultra-high-yield neutron tube of the present invention can reach 1×10 10 n / s or more. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a structural schematic diagram of the present invention;

[0046] Figure 2 Schematic diagram of the structure of the grid in an embodiment of the present invention.

[0047] The reference numerals are as follows:

[0048] 1-lower end sealing 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-connecting ring, 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 sealing Kovar. DETAILED DESCRIPTION

[0049] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments. Figure 1 As shown, it includes a hollow cylindrical ceramic shell 11, a heating and excitation assembly, an acceleration assembly and a target receiving assembly, wherein the heating and excitation assembly is installed at the lower end of the shell 11 and extends into the inside of the shell 11, the acceleration assembly is located inside the shell 11, and the target receiving assembly is installed at the upper end of the shell 11. The heating and excitation assembly is used to heat the gas stored in the neutron tube to form ions, which are accelerated by the acceleration assembly, so that the neutrons finally reach the target receiving assembly.

[0050] The heating and excitation assembly includes a sealing unit for sealing, 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.

[0051] The sealing unit includes a cylindrical lower sealing valve 1 with the same diameter as the 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 shell 11. The stem plate 17 is installed on the lower sealing valve 1. The outer diameter of the stem plate 17 matches the inner diameter of the lower sealing valve 1, and a sealing ring 16 is provided between the stem plate 17 and the inner surface of the lower sealing valve 1 for sealing. A storage 18 is provided on the upper end surface of the stem plate 17, so that the storage 18 is located inside the shell 11, and is used to store and place gaseous media and adjust the internal air pressure of the neutron tube. One end of the exhaust pipe 15 passes through the stem plate 17 and is connected to the storage 18, and the other end of the exhaust pipe 15 is connected to the external environment, and is used to transport gaseous media into the storage 18, and can also transport the air inside the shell 11 to the external environment.

[0052] The metal wire located inside the housing 11 is connected to the storage 18, so that the storage 18 is connected to an external power source through the metal wire.

[0053] The ion unit comprises a ceramic tube 4 and an ion source cover 20. The ion source cover 20 is arranged in the housing 11, and the ion source chassis 19, the rear cathode 21, the anode structure, the front cathode 22, the magnetic steel ring 23 and the grid 10 are arranged in the ion source cover 20 from bottom to top.

[0054] 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 .

[0055] 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.

[0056] The stem plate 17 is provided with a lead wire 2, which connects an external power source and an anode 8 inside the housing 11. The lead wire 2 includes a cathode wire, an anode wire and a ground terminal.

[0057] The magnetic steel structure includes a magnetic steel sleeve 3, a magnetic conductive sheet 5 and a magnetic steel column 6 which are connected in sequence and arranged in the magnetic steel cover. The magnetic conductive sheet 5 is provided with a first through hole for installing the outer magnetic steel. The upper end of the magnetic steel cover contacts the rear cathode 21.

[0058] A second through hole is formed on the upper end surface of the ion source cover 20, and the second through hole corresponds to the third through hole on the magnetic steel ring 23, and the grid 10 is located between the second through hole and the third through hole. When the skeleton aperture ratio D / d of the grid 10 is 4.0, as Figure 2 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%.

[0059] 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.

[0060] The accelerating assembly includes a conical accelerating pole 12. A fourth through hole corresponding to the third through hole is arranged at the lower end of the accelerating pole 12. The upper end of the accelerating pole 12 is connected to the inner wall of the housing 11. The diameter of the upper end of the accelerating pole 12 is larger than that of the lower end.

[0061] The target receiving assembly includes a target 13, a target substrate 24, a target bottom magnet 25 and an upper end sealing Kovar 26. The lower end of the upper end sealing Kovar 26 is connected to the upper end of the housing 11, the target substrate 24 is installed in the upper end sealing Kovar 26, and a connecting ring 14 is provided between the target substrate 24 and the upper end sealing Kovar 26 for sealing, the target 13 is provided on the lower surface of the target substrate 24, and the axial cross section of the lower end surface of the target 13 is in the shape of an arc. The upper end of the accelerating pole 12 corresponds to the target 13.

[0062] 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 .

[0063] In this embodiment, in order to form a suitable accelerating electric field, a conical accelerating electrode 12 is used, and the diameter of the lower entrance of the accelerating electrode 12 is increased from Φ8 to Φ18mm, thereby shortening the length of the accelerating electrode and increasing the size of the target 13, so that the target 13 is increased from Φ38 to Φ45mm, and the overall length of the neutron tube is also shortened, so that the specification of the neutron tube is Φ65×320mm. 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 light 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. The aperture of the exit of the accelerating electrode 12 is compatible with the diameter of the housing 11, and it can be installed normally. The accelerating electrode gap length refers to the distance from the upper end face of the ion source cover 20 to the entrance of the accelerating electrode 12.

[0064] 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 passes through the upper end sealing ferrule 26 and extends to the upper end of the outer shell 11. 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. The installation method of the neutron tube is as follows:

[0065] Step 1: install the grid 10 into the upper end of the ion source cover 20 and fit it with the second through hole.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] Step 5, use Φ0.8 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.

[0070] 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.

[0071] 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.

[0072] Step 8: Pass the lead wire 2 through the lower end of the housing 11 and connect it to the ground.

[0073] Step 9, high temperature degassing, the formed neutron tube is placed in an environment of 450°C for one hour for high temperature degassing.

Claims

1. An ultra-high-yield neutron tube, comprising a housing (11), a heating and excitation component, an accelerating component and a target receiving component; the heating and excitation component is mounted at the lower end of the housing (11) and extends upward to the interior of the housing (11); the accelerating component is located inside the housing (11), and the input end of the accelerating component corresponds to the output end of the heating and excitation component; the target receiving component is mounted at the upper end of the housing (11), and the output end of the accelerating component corresponds to the target receiving component, so that excited ions located in the heating and excitation component are accelerated by the accelerating component and reach the target receiving component; Features: The heating and exciting component comprises a sealing unit for sealing the lower end of the housing (11), a storage container (18) for storing the medium, and an ion unit for ionizing and exciting the medium; The reservoir (18) is installed in the sealing unit and communicated with the ion unit, and is used to release gas into 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); 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), the second through hole corresponds to a fourth through hole provided at the input end of the acceleration component and a third through hole provided on the magnetic steel ring (23), and the grid (10) is located between the second through hole and the third through hole.

2. The ultra-high yield neutron tube according to claim 1, characterized in that: The accelerating component comprises a conical cone-shaped accelerating electrode (12), the diameter of the output end of the accelerating electrode (12) being larger than the diameter of the input end; the input end of the accelerating electrode (12) is provided with a fourth through hole corresponding to 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 corresponds to the input end of the target receiving component.

3. The ultra-high-yield neutron tube according to claim 1 or 2, characterized in that: 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 output end of the accelerating electrode (12) corresponds to the lower end surface of the target (13); The lower end of the upper end sealing valve (26) is connected to the upper end of the housing (11) and is used to seal the upper end of the housing (11); The target substrate (24) is installed in the upper sealing kovar (26); the target (13) is arranged on the lower end surface of the target substrate (24); the axial cross section of the lower end surface of the target (13) is in the shape of a circular arc; the target bottom magnetic steel (25) is installed between the target substrate (24) and the upper sealing kovar (26) and is used to form a magnetic field at the lower end of the target (13), so that ions move in the direction of the target bottom magnetic steel (25) through the magnetic field to bombard the target surface of the target (13); The upper end surface of the target substrate (24) is provided with an external magnetic steel ring structure; The lower end side wall of the external magnetic steel ring structure is connected to the inner surface of the target bottom magnetic steel (25), and the upper end passes through the upper end sealing valve (26) and extends to the upper end outside of the casing (11).

4. The ultra-high-yield neutron tube according to claim 3, 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.

5. The ultra-high-yield neutron tube according to claim 4, characterized in that: The sealing unit comprises a lower end sealing valve (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 valve (1), and the 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 plate (17) and is connected to the reservoir (18), and the other end is connected to the external environment, so as to transport the medium into the reservoir (18); The storage device (18) is connected to an external power supply device via a metal wire.

6. The ultra-high-yield neutron tube according to claim 5, characterized in that: The heating excitation component also includes a magnetic steel structure; The magnetic steel structure comprises a magnetic steel sleeve (3), a magnetic conductive sheet (5) and a magnetic steel column (6) which are arranged in sequence from bottom to top in the magnetic steel cover, 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).

7. The ultra-high-yield neutron tube according to claim 6, 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).

8. The ultra-high-yield neutron tube according to claim 7, 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 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 Φ65×320 mm.

10. A method for installing an ultra-high yield neutron tube, characterized in that: Based on the ultra-high yield neutron tube described in claim 1, the installation steps are as follows: Step 1, inserting the grid (10) into the upper end of the ion source cover (20) and fitting it with the second through hole; Step 2, 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; Step 3, 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); 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; Step 5, 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 to an external power source; Step 6, aligning and connecting the upper end of the ion source cover (20) with the upper end of the ion source cover chassis (19); Step 7, installing the reservoir (18) on the sealing unit; Step 8, 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; Step 9, 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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