Rotary neutron target

Abstract

The utility model provides a rotary neutron target. The rotary neutron target comprises a neutron generation layer, a hydrogen diffusion layer and a cooling device, the cooling device comprises a cooling substrate and a rotating shaft, the cross section of the cooling substrate is circular, and the rotating shaft is vertically and fixedly connected to the circle center of the cooling substrate; the cross sections of the neutron generation layer and the hydrogen diffusion layer are of a first annular structure and a second annular structure respectively, and the first annular structure and the second annular structure are the same in shape and area. The hydrogen diffusion layer, the neutron generation layer and the cooling substrate are coaxially arranged, the hydrogen diffusion layer is arranged above the cooling substrate, and the neutron generation layer completely covers the hydrogen diffusion layer. According to the structure, all protons enter the hydrogen diffusion layer, and heat generated by the neutron generation layer and the hydrogen diffusion layer on the rotating neutron target is rapidly taken away, so that the heat is uniformly distributed, and high temperature of the target material caused by proton aggregation is avoided; according to the structure, proton energy deposition is basically in the hydrogen diffusion layer, the neutron generation layer is effectively protected, and the service life of the neutron target is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of neutron sources, and particularly relates to a rotating neutron target. Background Art

[0002] As the physical basis of a neutron source, a neutron target has a very important influence on neutron yield and neutron energy spectrum. When particle beams with different energies and beam sizes bombard different target materials, the obtained neutron yield and neutron energy spectrum are also different. When the selected proton energy is lower than 4 MeV, a lithium target is the best choice.

[0003] During the process of proton beam bombarding the target, heat accumulation will occur. The melting point of lithium is only 180 °C. Under high-power working conditions, excessive heat load will cause lithium to heat up rapidly, resulting in damage to the lithium layer, and is more likely to further damage the substrate, thereby destroying the overall structure of the neutron target. In addition, excessive accumulation of protons in the target will cause the target material to blister and be damaged. If considering directly introducing protons into water for cooling, the target itself may be damaged during operation due to insufficient mechanical strength.

[0004] In addition, most of the neutron targets commonly used in this field are stationary targets, which are more likely to cause concentrated heat accumulation, exacerbating the damage of the neutron target during the process of proton beam bombarding the target. Summary of the Utility Model

[0005] In order to overcome the defects of proton aggregation, blistering problems and too high working temperature generated when protons bombard a neutron target in the prior art, the utility model provides a rotating neutron target. Through the structural design of the rotating neutron target of the present application, all protons enter the hydrogen diffusion layer, thereby quickly taking away the heat generated by the neutron generation layer and the hydrogen diffusion layer on the rotating neutron target, making the heat distribution uniform, reducing the heat dissipation pressure, avoiding the high temperature caused by proton aggregation in the target material, and further avoiding the structural damage caused by blistering; and, this structure can also make the proton energy deposition basically in the hydrogen diffusion layer, effectively protecting the neutron generation layer and improving the working life of the neutron target.

[0006] The utility model solves the above technical problems through the following technical solutions:

[0007] The utility model provides a rotating neutron target, which includes a neutron generation layer, a hydrogen diffusion layer and a cooling device;

[0008] The cooling device includes a cooling substrate and a rotating shaft. The cross-section of the cooling substrate is circular, and the rotating shaft is vertically fixedly connected to the center of the cooling substrate;

[0009] The cross-section of the neutron generation layer and the cross-section of the hydrogen diffusion layer are a first annular structure and a second annular structure respectively, and the shapes and areas of the first annular structure and the second annular structure are the same; both the hydrogen diffusion layer and the neutron generation layer are coaxially arranged with the cooling substrate, the hydrogen diffusion layer is arranged above the cooling substrate, and the neutron generation layer completely covers the hydrogen diffusion layer.

[0010] In the present utility model, by adding a hydrogen diffusion layer between the neutron generation layer and the cooling substrate and designing a cooling substrate with a rotating shaft structure, the rotation of the neutron target can be realized, thereby prolonging the service life of the neutron target and enabling it to work stably for a long time.

[0011] In the present utility model, those skilled in the art should know that there is no requirement for a fixed ratio between the areas of the first annular structure and the second annular structure and the area of the cooling substrate, and their sizes are designed by comprehensively considering proton beam irradiation and the rotation of the neutron target.

[0012] In some embodiments, the outer diameter of the cooling substrate is greater than the outer diameter of the neutron generation layer, or the outer diameter of the cooling substrate is greater than the outer diameter of the hydrogen diffusion layer.

[0013] In some embodiments, the thickness of the cooling substrate is 5 - 10 mm.

[0014] In some embodiments, the inner diameters of the neutron generation layer and the hydrogen diffusion layer are the same, both being 40 cm - 140 cm.

[0015] In some embodiments, the outer diameters of the neutron generation layer and the hydrogen diffusion layer are the same, both being 60 cm - 160 cm.

[0016] In some embodiments, the thickness of the neutron generation layer is 150 μm - 300 μm; the thickness of the neutron generation layer can be jointly determined by the neutron yield and the Bragg peak position.

[0017] In a certain embodiment, when bombarding the rotating neutron target with 2.8 MeV protons, under this energy condition, the Bragg peak position is calculated, and on this premise, several thickness gradients less than the Bragg peak depth are set to calculate the neutron yield, thereby obtaining the optimal layer thickness of the neutron generation layer.

[0018] In some embodiments, the thickness of the hydrogen diffusion layer is 30 μm - 60 μm; the thickness of the hydrogen diffusion layer is jointly determined by the Bragg peak position, the energy deposition distribution, and the thermal conductivity.

[0019] In one embodiment, under the condition of 2.8 MeV protons, the position of protons in the hydrogen diffusion layer is preliminarily determined, and the layer thickness is roughly established. On this basis, the above neutron generation layer and hydrogen diffusion layer are combined as a model to calculate the energy deposition distribution and determine the specific thickness of the hydrogen diffusion layer.

[0020] In some embodiments, an annular circulation area, a first water inlet channel, and a first water outlet channel are provided inside the cooling substrate; the center of the annular circulation area coincides with the center of the cooling substrate, and both the first water inlet channel and the first water outlet channel are arranged along the radial direction of the cooling substrate; the outlet of the first water inlet channel and the inlet of the first water outlet channel are respectively connected to the annular circulation area.

[0021] In a specific embodiment, the hydrogen diffusion layer is arranged directly above the annular circulation area; through this design, the heat generated by the neutron generation layer and the hydrogen diffusion layer can be quickly removed.

[0022] In a specific embodiment, the cross-sectional shape of the annular circulation area is the same as that of the first annular structure and the second annular structure.

[0023] In a specific embodiment, the inner diameter of the annular circulation area is less than or equal to the inner diameter of the neutron generation layer or the hydrogen diffusion layer.

[0024] In a specific embodiment, the outer diameter of the annular circulation area is greater than or equal to the outer diameter of the neutron generation layer or the hydrogen diffusion layer.

[0025] In a specific embodiment, the annular circulation area includes a plurality of annular channels; the centers of the annular channels coincide with the center of the cooling substrate; the outlet of the first water inlet channel and the inlet of the first water outlet channel are arranged opposite to each other, and the outlet of the first water inlet channel and the inlet of the first water outlet channel are respectively communicated with the annular channels.

[0026] In a preferred embodiment, the cross-section of the annular channel is circular.

[0027] In a preferred embodiment, the diameter of the annular channel is 1 - 5 mm, for example, 3 mm.

[0028] In a preferred embodiment, the number of the annular channels is 10 - 50, for example, 20.

[0029] In a preferred embodiment, the annular channels are arranged in sequence along the radial direction of the cooling substrate.

[0030] In a specific embodiment, a water inlet and a water outlet are provided at the upper part of the rotating shaft, and a second water inlet channel and a second water outlet channel are arranged inside the rotating shaft. The second water inlet channel is arranged inside the second water outlet channel. One end of the second water inlet channel is connected to the water inlet, and the other end is connected to the first water inlet channel. One end of the second water outlet channel is connected to the water outlet, and the other end is connected to the first water outlet channel.

[0031] In some embodiments, the material of the neutron generation layer is metallic lithium.

[0032] In some embodiments, the material of the hydrogen diffusion layer is metallic palladium or metallic tantalum. Among them, both the palladium and the tantalum are pure substances.

[0033] In the present utility model, the material of the cooling substrate can be determined by the thermal conductivity.

[0034] In some embodiments, the material of the cooling substrate is copper.

[0035] The positive and progressive effects of the present utility model are as follows:

[0036] 1. In the rotating neutron target of the present application, the heat generated by the neutron generation layer and the hydrogen diffusion layer can be quickly removed through the cooling device, thereby avoiding damage to the target layer structure caused by high temperature.

[0037] 2. Through the structural design of the rotating neutron target of the present application, all protons enter the hydrogen diffusion layer, avoiding structural damage caused by proton aggregation leading to blistering of the target material.

[0038] 3. Through the structural design of the rotating neutron target of the present application, the proton energy deposition is also basically in the hydrogen diffusion layer, effectively protecting the neutron generation layer, thereby effectively improving the working life of the neutron target. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is the front view sectional view of the rotating neutron target of Example 1;

[0040] Figure 2 For Figure 1 The partial enlarged view of the connection between the rotating shaft and the cooling substrate in

[0041] Figure 3 For Figure 1 The front view sectional view of the outer edge of the cooling substrate in

[0042] Figure 4 For Figure 3 The partial enlarged front view sectional view of the annular channel of the cooling substrate in

[0043] Figure 5Top view of the cross-section of a partial annular channel in the rotating neutron target of Example 1;

[0044] Figure 6 Cross-sectional view of the cooling substrate in the rotating neutron target of Example 1;

[0045] Explanation of reference numerals:

[0046] Water inlet 1

[0047] Water outlet 2

[0048] Second water inlet channel 3

[0049] Second water outlet channel 4

[0050] Rotating shaft 5

[0051] First water inlet channel 6

[0052] First water outlet channel 7

[0053] Annular circulation area 8

[0054] Neutron generation layer 9

[0055] Hydrogen diffusion layer 10

[0056] Cooling substrate 11

[0057] Annular channel 12. Detailed implementation manner

[0058] The following is a preferred embodiment and is described in more clearly and completely in conjunction with the drawings for the present utility model.

[0059] Example 1

[0060] This embodiment provides a rotating neutron target, which is used to bombard protons (not shown in the figure) with an energy of 2.8 MeV on it, and the proton beam current is 10 mA to generate neutrons. After calculation, the Bragg peak of the proton beam in lithium is 288 μm.

[0061] Figure 1 Front view sectional view of the rotating neutron target of this embodiment; Figure 2 For Figure 1Partial enlarged view of the connection between the rotating shaft and the cooling substrate. The rotating neutron target includes a neutron generation layer 9, a hydrogen diffusion layer 10, and a cooling device; the cooling device includes a cooling substrate 11 and a rotating shaft 5. The cross-section of the cooling substrate 11 is circular, and the rotating shaft 5 is vertically fixed to the center of the cooling substrate 11. The cross-sections of the neutron generation layer 9 and the hydrogen diffusion layer 10 are a first annular structure and a second annular structure respectively, and the shapes and areas of the first annular structure and the second annular structure are the same. The hydrogen diffusion layer 10 and the neutron generation layer 9 are both coaxially arranged with the cooling substrate 11. The hydrogen diffusion layer 10 is arranged above the cooling substrate 11, and the neutron generation layer 9 completely covers the hydrogen diffusion layer 10.

[0062] Among them, the material of the neutron generation layer 9 is metallic lithium; the material of the hydrogen diffusion layer 10 is metallic palladium or metallic tantalum; the material of the cooling substrate 11 is copper; the material of the rotating shaft 5 is stainless steel or aluminum alloy, and it is welded to the cooling substrate 11.

[0063] Among them, the outer diameter of the cooling substrate 11 is greater than the outer diameter of the neutron generation layer 9 or the outer diameter of the hydrogen diffusion layer 10; the thickness of the cooling substrate 11 is 5 - 10 mm; the inner diameters of the neutron generation layer 9 and the hydrogen diffusion layer 10 are the same, both being 80 cm; the outer diameters of the neutron generation layer 9 and the hydrogen diffusion layer 10 are the same, both being 100 cm; the thickness of the neutron generation layer 9 is 150 μm; the thickness of the hydrogen diffusion layer 10 is 50 μm. In order to make protons deposit in the hydrogen diffusion layer 10, ensure the maximum neutron yield, and make most of the energy deposition of protons located in the hydrogen diffusion layer 10, the thickness of the neutron generation layer 9 is less than the depth of the Bragg peak. In this embodiment, the thickness of the neutron generation layer 9 is 52% of the depth of the Bragg peak.

[0064] Figure 3 Front view sectional view at the outer edge of the cooling substrate 11 of the rotating neutron target; Figure 4 For Figure 3 Front view sectional view of the partial enlarged view at the annular channel 12 of the cooling substrate 11 in Figure 5 Top view of the cross-section of a part of the annular channels 12 in the rotating neutron target of this embodiment; Figure 6 Cross-sectional view of the cooling substrate 11 in the rotating neutron target of this embodiment.

[0065] Among them, an annular flow area 8, a first water inlet channel 6 and a first water outlet channel 7 are arranged inside the cooling substrate 11; the center of the annular flow area 8 coincides with the center of the cooling substrate 11, and both the first water inlet channel 6 and the first water outlet channel 7 are arranged along the radial direction of the cooling substrate 11; the outlet of the first water inlet channel 6 and the inlet of the first water outlet channel 7 are respectively connected to the annular flow area 8. The hydrogen diffusion layer 10 is arranged directly above the annular flow area; the cross-sectional shape of the annular flow area 8 is the same as that of the first annular structure and the second annular structure, so as to ensure that the cooling medium can fully cool the neutron generation layer 9 and the hydrogen diffusion layer 10, and can quickly take away the heat, avoiding structural damage problems such as melting and falling off of the neutron generation layer 9 due to high temperature. The annular flow area 8 includes a plurality of annular channels 12; the centers of the annular channels 12 coincide with the center of the cooling substrate 11; the outlet of the first water inlet channel 6 and the inlet of the first water outlet channel 7 are arranged opposite to each other, and the outlet of the first water inlet channel 6 and the inlet of the first water outlet channel 7 are respectively communicated with the annular channels 12. The radial cross-section of each annular channel 12 is circular, with a diameter of 3 mm and a number of 20, and they are arranged in sequence along the radial direction of the cooling substrate 11. The cooling substrate 11 is an integral structure, and grooves are directly machined inside to ensure its sealing performance.

[0066] An inlet 1 and an outlet 2 are provided at the upper part of the rotating shaft 5, and the rotating shaft 5 is designed in a sandwich structure, and a second water inlet channel 3 and a second water outlet channel 4 are arranged inside it. The second water inlet channel 3 is arranged inside the second water outlet channel 4 and is separated by a solid wall; one end of the second water inlet channel 3 is connected to the inlet 1, and the other end is connected to the first water inlet channel 6; one end of the second water outlet channel 4 is connected to the outlet 2, and the other end is connected to the first water outlet channel 7.

[0067] The cooling medium in the cooling substrate 11 is cooling water. Combined Figure 1 and Figure 2 , the cooling medium enters from the inlet 1, flows through the second water inlet channel 3, enters the annular channels 12 through the first water inlet channel 6, and after circulation, flows into the second water outlet channel 4 through the first water outlet channel 7, and finally discharges from the outlet 2.

[0068] Through the structural design of the rotating neutron target in this embodiment, protons are basically deposited in the hydrogen diffusion layer 10, avoiding the problem of proton aggregation and deposition in the neutron generation layer 9 and the cooling substrate 11, and also strengthening the mechanical strength of the target body, thereby effectively improving the working life of the neutron target.

[0069] In this embodiment, the thickness of the neutron generation layer 9 is less than the Bragg peak depth of the proton beam in the neutron generation layer 9. While achieving the maximum neutron yield, protons are deposited into the hydrogen diffusion layer 10, effectively avoiding the problem of aggregation and blistering after proton deposition and strengthening the mechanical strength of the target so that it will not be damaged during operation. At the same time, the rotating structure and the cooling substrate 11 can quickly cool the first two layers to rapidly remove the generated heat, preventing the target material from being damaged due to high temperature. Thereby, the working cycle of the neutron target is effectively improved.

[0070] So far, the technical solution of the present invention has been described in conjunction with the embodiments shown in the drawings. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and these changed or substituted technical solutions will fall within the protection scope of the present invention.

Claims

1. A rotating neutron target, characterized in that, It includes a neutron generation layer, a hydrogen diffusion layer and a cooling device; The cooling device includes a cooling substrate and a rotating shaft. The cross-section of the cooling substrate is circular, and the rotating shaft is vertically and fixedly connected to the center of the cooling substrate; The cross-sections of the neutron generation layer and the hydrogen diffusion layer are a first annular structure and a second annular structure respectively, and the shapes and areas of the first annular structure and the second annular structure are the same; The hydrogen diffusion layer and the neutron generation layer are both coaxially arranged with the cooling substrate. The hydrogen diffusion layer is arranged above the cooling substrate, and the neutron generation layer completely covers the hydrogen diffusion layer; 2. The rotating neutron target according to claim 1, wherein The outer diameter of the cooling substrate is greater than the outer diameter of the neutron generation layer, or the outer diameter of the cooling substrate is greater than the outer diameter of the hydrogen diffusion layer; The thickness of the cooling substrate is 5 - 10 mm; 3. The rotating neutron target according to claim 1, wherein, The inner diameters of the neutron generation layer and the hydrogen diffusion layer are the same, both being 40 cm - 140 cm; The outer diameters of the neutron generation layer and the hydrogen diffusion layer are the same, both being 60 cm - 160 cm; 4. The rotating neutron target according to claim 1, characterized in that, The thickness of the neutron generation layer is 150 μm - 300 μm; The thickness of the hydrogen diffusion layer is 30 μm - 60 μm; 5. The rotating neutron target according to claim 1, wherein An annular flow area, a first water inlet channel and a first water outlet channel are arranged inside the cooling substrate; The center of the annular flow area coincides with the center of the cooling substrate, and the first water inlet channel and the first water outlet channel are both arranged along the radial direction of the cooling substrate; The outlet of the first water inlet channel and the inlet of the first water outlet channel are respectively connected to the annular flow area; 6. The rotating neutron target according to claim 5, wherein The hydrogen diffusion layer is arranged directly above the annular flow area; The shape of the cross-section of the annular flow area is the same as that of the first annular structure and the second annular structure; The inner diameter of the annular flow area is less than or equal to the inner diameter of the neutron generation layer or the hydrogen diffusion layer; The outer diameter of the annular flow area is greater than or equal to the outer diameter of the neutron generation layer or the hydrogen diffusion layer; 7. The rotating neutron target according to claim 5, wherein, The annular flow area includes a number of annular channels; the centers of the annular channels coincide with the center of the cooling substrate; the outlet of the first water inlet channel and the inlet of the first water outlet channel are arranged oppositely, and the outlet of the first water inlet channel and the inlet of the first water outlet channel are respectively communicated with the annular channels; 8. The rotating neutron target according to claim 7, wherein The annular channels satisfy one or more of the following conditions: ① The radial cross-section of the annular channel is circular; ② The diameter of the annular channel is 1 - 5 mm; ③ The number of the annular channels is 10 - 50; ④ The annular channels are arranged in sequence along the radial direction of the cooling substrate; 9. The rotating neutron target according to claim 5, wherein An inlet and an outlet are arranged at the upper part of the rotating shaft, and a second water inlet channel and a second water outlet channel are arranged inside the rotating shaft. The second water inlet channel is arranged inside the second water outlet channel; one end of the second water inlet channel is connected to the inlet, and the other end is connected to the first water inlet channel; one end of the second water outlet channel is connected to the outlet, and the other end is connected to the first water outlet channel; 10. The rotating neutron target according to claim 1, characterized in that, The material of the neutron generation layer is metallic lithium; The material of the hydrogen diffusion layer is metallic palladium or metallic tantalum; The material of the cooling substrate is copper.

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