Convex target neutron tube

Abstract

The application discloses a convex target neutron tube, which comprises a magnetic steel ring, a target sheet, a target body, a shell and an accelerating electrode, the accelerating electrode is fixedly connected with the target body, the magnetic steel ring is arranged on the outer side of the accelerating electrode, and the magnetic steel ring is close to the end surface of the target body connected with the accelerating electrode; the target sheet is arranged in the interior of the target body and is fixedly connected with the target body; the shell is arranged on the outer side of the accelerating electrode, one end of the shell is connected with the target body, and the other end is connected with a source structure member; the magnetic steel ring is arranged on the outer side of the accelerating electrode, the magnetic steel ring further forms an axial dispersion magnetic field on the outer convex spherical surface of the target sheet, a secondary electron magnetic suppression structure of the neutron tube is formed, and the secondary electron can be effectively suppressed; the problem that the secondary electron is accelerated by the accelerating electric field to form a harmful target flow, the power consumption of the neutron tube is increased, and the working life index is affected is solved; the outer convex spherical target surface is a gradient distribution deuterium absorption titanium film, the utilization rate of the deuterium in the target of the neutron tube is improved, and the neutron yield index of the neutron tube is improved.

Description

Technical Field

[0001] This invention belongs to the field of well logging technology and relates to a convex target neutron tube. Background Technology

[0002] Existing neutron tubes generally consist of an insulating shell, a Penning ion source, an accelerating electrode, and a target. The Penning ion source generates deuterium ions, which are accelerated and then strike a tritium-containing target, resulting in the following reaction: It emits fast neutrons of about 14 MeV. When the accelerated deuterium ions bombard the target, they produce spilled electrons. These secondary electrons may be accelerated in the opposite direction by the accelerating electric field to form a harmful target flux, increase the power consumption of the neutron tube, and also cause sputtering by bombarding the surface of the ion source.

[0003] Two secondary electron suppression methods are typically introduced in neutron tube structures: magnetic field suppression and reverse electric field suppression. The magnetic field suppression method usually involves embedding a magnetic steel column outside the target substrate to form an axially distributed magnetic field on the target surface. However, the magnetic field formed is relatively weak and its effect is not obvious.

[0004] Existing neutron tubes use planar targets, or concave spherical or conical targets to increase the target area. These curved targets present two problems: First, during the coating process, the equipment structure affects the formation of a titanium film density distribution on the target surface where the outer radial surface has a higher density than the inner core. Second, both theoretical calculations and practical experience have shown that the spot formed by the ion beam on the target surface is not a uniformly distributed circular area, but rather exhibits a distribution with high density in the central region and gradually decreasing density in the annular intervals. Therefore, during normal operation, the neutron tube consumes a significant amount of tritium in the central region of the target surface, which is a major factor affecting the yield and service life of neutron tubes. Summary of the Invention

[0005] The purpose of this invention is to solve the problems in the prior art and provide a convex target neutron tube.

[0006] To achieve the above objectives, the present invention employs the following technical solution:

[0007] A convex target neutron tube includes a magnetic ring, a target plate, a target body, a shell, an accelerating electrode, and a source substructure.

[0008] The accelerating electrode is fixedly connected to the target, and the magnetic ring is sleeved on the outside of the accelerating electrode, with the magnetic ring close to the end face where the accelerating electrode is connected to the target.

[0009] The target piece is disposed inside the target body and is fixedly connected to the target body;

[0010] The outer shell is fitted over the outside of the accelerating electrode, with one end connected to the target and the other end connected to the source substructure.

[0011] A further improvement of the present invention is that:

[0012] The target body includes a target base and a connecting ring;

[0013] The connecting ring is sleeved on the outside of the target substrate, the target sheet is disposed inside the target substrate, and the target substrate is connected to the accelerating electrode.

[0014] The target substrate has a groove inside, and the target piece is embedded in the groove.

[0015] The target plate has an outwardly convex spherical structure.

[0016] A gradient-distributed deuterium-absorbing titanium film is disposed on the outer convex spherical surface of the target.

[0017] The target plate has air guide grooves on its side.

[0018] The accelerating electrode is connected to the magnetic ring and the target body via a fixing ring;

[0019] The fixing ring is sequentially sleeved on the outside of the accelerating electrode and the target, with the two end faces of the accelerating electrode and the target abutting against each other.

[0020] The magnetic ring is fitted onto the outside of the fixed ring.

[0021] The outer shell is connected to the target via Kovar;

[0022] The Kovar is sleeved on the outside of the fixing ring, and the end face of the Kovar near the accelerating electrode is fixedly connected to one end of the outer shell.

[0023] The Kovar is welded to the outer shell.

[0024] The shell is a ceramic shell.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] This invention discloses a convex target neutron tube, in which a magnetic ring is arranged on the outside of the accelerating electrode. The magnetic ring forms an axially radiating magnetic field at one end of the accelerating electrode. The magnetic ring and the accelerating electrode together constitute a secondary electron magnetic suppression structure of the neutron tube, which can effectively suppress secondary electrons. The magnetic field distribution on the target surface is reasonable, the structure is compact, the magnetic field formed is strong, and the effect is obvious. It helps to increase the yield of the neutron tube, reduce the power consumption of the neutron tube, and help to improve the life index of the neutron tube.

[0027] Furthermore, the target structure of the present invention is a convex spherical structure, combined with a titanium film with a gradient distribution on the convex spherical surface, forming a non-uniform tritium-absorbing titanium film on the neutron tube target surface, which can effectively improve the tritium utilization rate in the target film and increase the neutron yield.

[0028] Furthermore, the side of the target sheet of the present invention has an air guide groove, which provides an exhaust channel and improves the high-temperature exhaust effect. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the structure of the present invention.

[0031] Wherein: 1-Magnetic steel ring; 2-Target plate; 3-Target substrate; 4-Connecting ring; 5-Fixing ring; 6-Kovar; 7-Outer shell; 8-Accelerating electrode; 9-Gas guide groove; 10-Ion source structural component. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0033] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0034] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0035] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0036] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0037] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0038] The present invention will now be described in further detail with reference to the accompanying drawings:

[0039] See Figure 1 The present invention discloses a convex target neutron tube, including a magnetic ring 1, a target plate 2, a target substrate 3, a connecting ring 4, a fixing ring 5, a Kovar 6, a shell 7, an accelerating electrode 8, a gas guide groove 9, and an ion source structure 10.

[0040] Example 1

[0041] One end of the accelerating electrode 8 is connected to the target substrate 3. The connecting ring 4 is sleeved on the outside of the target substrate 3 and welded to the target substrate 3. The magnetic ring 1 is sleeved on the outside of the accelerating electrode 8. One end of the accelerating electrode 8 abuts against one end of the target substrate 3. The magnetic ring 1 is sleeved on the outside of the accelerating electrode 8 near the target substrate 3. The target sheet 2 is set inside the target substrate 3. The specific connection method is as follows: a groove is opened on the end face of the target substrate 3 near the accelerating electrode 8, and the target sheet 2 is embedded in the groove. The outer shell 7 is sleeved on the outside of the accelerating electrode 8 and connected to the target substrate 3. The end of the outer shell 7 away from the target substrate 3 is connected to the ion source structure 10.

[0042] The present invention also discloses another embodiment in which the target 2 is a convex spherical structure.

[0043] The present invention also discloses another embodiment in which a titanium film is gradient distributed on the outer wall of the target 2, and the coating forms a non-uniform radial gradient distribution film with high density in the central region, thereby improving the effective utilization rate of tritium gas.

[0044] The present invention also discloses another embodiment in which an air guide groove 9 is formed on the side of the target piece 2, and the target side air guide groove solves the exhaust treatment problem.

[0045] The present invention also discloses another embodiment, wherein the accelerating electrode 8 is connected to the magnetic steel ring 1 and the target substrate 3 through the fixing ring 5. The fixing ring 5 is sequentially sleeved on the outside of the accelerating electrode 8, and the magnetic steel ring 1 is sleeved on the outside of the fixing ring 5. The fixing ring 5 connects the accelerating electrode 8 and the target substrate 3 together. The connecting ring 4 is sleeved on the outside of the target substrate 3 and located on the inside of the fixing ring 5. One end of the outer shell 7 is also connected to Kovar 6, which is sleeved on the outside of the fixing ring 5. Kovar 6 is fixedly connected to the end of the outer shell 7 near the accelerating electrode 8.

[0046] In this embodiment of the invention, the housing 7 is a ceramic housing.

[0047] This invention also discloses a tooling method:

[0048] Before the neutron tube is assembled, the magnet ring 1 is installed on the fixed ring 5, and then the accelerating electrode 8 is installed. After it is tightened, the accelerating electrode 8 is welded to the fixed ring 5 using laser welding pulse spot welding. The magnet ring 1 is also fixed on the fixed ring 5, thus forming the accelerating electrode structure.

[0049] The connecting ring 4 is pre-brazed to the target substrate 3. The target substrate 3 and the connecting ring 4 are vacuum brazed to form the target body, and leak testing is performed to confirm the sealing performance. The Kovar 6 is first brazed to the outer shell 7.

[0050] Before the neutron tube is assembled, the target 2 is coated in stages using a special coating tool to form a gradient titanium film on the target surface, and then undergoes a tritium filling process to complete the tritium titanium film target.

[0051] During assembly, the target plate 2 with the side air guide groove 9 is embedded into the groove of the target base 3, and the target plate 2 is pressed inward at several points evenly on the outer edge of the target base 3. The assembly is a tight fit to ensure sufficient heat dissipation. The accelerating electrode 8, the magnet ring 1, the fixing ring 5, the target base 3, and the connecting ring 4, which are spot-welded together, are then put into the shell composed of the outer shell 7 and the Kovar 6, and are tightened into place in the Kovar 6. Finally, the outer edge formed by the three sides of the Kovar 6, the connecting ring 4, and the fixing ring 5 is sealed by argon arc welding. Cooling protection is performed after the argon arc welding is completed.

[0052] The embodiments of the present invention produce the following effects:

[0053] This invention discloses a neutron tube with a built-in front-magnetic ring for magnetic suppression and a convex target structure. The neutron tube in this embodiment uses a built-in permanent magnet material to form an axially divergent magnetic field of appropriate magnetic induction intensity at the front end of the neutron tube target surface, constituting a secondary electron magnetic suppression structure for the neutron tube. At the same time, the target is designed as a convex spherical structure, and a unique multi-stage overlapping coating process is used to form a non-uniform tritium-absorbing titanium film on the neutron tube target surface. This can effectively improve the tritium utilization rate in the target film, increase the neutron yield, and reduce the target current, thereby reducing the power consumption of the neutron tube.

[0054] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A convex target neutron tube, characterized in that, It includes a magnetic ring (1), a target plate (2), a target body, a shell (7), an accelerating electrode (8), and an ion source structure (10). The accelerating electrode (8) is fixedly connected to the target, and the magnetic ring (1) is sleeved on the outside of the accelerating electrode (8), with the magnetic ring (1) close to the end face where the accelerating electrode (8) is connected to the target. The target piece (2) is disposed inside the target body and is fixedly connected to the target body; The outer shell (7) is fitted on the outside of the accelerating electrode (8), with one end of the outer shell (7) connected to the target and the other end connected to the source substructure. The target (2) is a convex spherical structure; The target sheet (2) has a gradient-distributed deuterium-absorbing titanium film on its convex spherical surface, and the coating forms a non-uniform radial gradient distribution film with high density in the central region.

2. The convex target neutron tube according to claim 1, characterized in that, The target body includes a target base (3) and a connecting ring (4); The connecting ring (4) is sleeved on the outside of the target substrate (3), the target sheet (2) is disposed inside the target substrate (3), and the target substrate (3) is connected to the accelerating electrode (8).

3. A convex target neutron tube according to claim 2, characterized in that, The target substrate (3) has a groove inside, and the target piece (2) is embedded in the groove.

4. A convex target neutron tube according to any one of claims 1-3, characterized in that, The side of the target (2) has an air guide groove (9).

5. A convex target neutron tube according to claim 1, characterized in that, The accelerating electrode (8) is connected to the magnetic ring (1) and the target body through the fixing ring (5); The fixing ring (5) is sequentially sleeved on the outside of the accelerating electrode (8) and the target, with the two end faces of the accelerating electrode (8) abutting against each other. The magnetic ring (1) is sleeved on the outside of the fixed ring (5).

6. A convex target neutron tube according to claim 5, characterized in that, The outer shell (7) is connected to the target via Kovar (6); The Kovar (6) is sleeved on the outside of the fixing ring (5), and the end face of the Kovar (6) near the accelerating electrode (8) is fixed to one end of the outer shell (7).

7. A convex target neutron tube according to claim 6, characterized in that, The Kovar (6) is welded to the outer shell (7).

8. A convex target neutron tube according to claim 1, characterized in that, The outer shell (7) is a ceramic shell.

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