A pile base slow positron source, control method and reactor

Abstract

A kind of slow positron source of pile base, control method and reactor belong to nuclear power field.The slow positron source of pile base includes slow positron generating component, outer sleeve, heavy water tank sleeve and sealing component;Heavy water tank sleeve is connected into heavy water tank, outer sleeve is inserted into heavy water tank by heavy water tank sleeve and makes end submerged in heavy water;Slow positron generating component is arranged at the end of outer sleeve and is enclosed in outer sleeve;Sealing component includes heavy water sealing mechanism and light water sealing mechanism, heavy water sealing mechanism encloses the gap between heavy water tank sleeve and outer sleeve, and light water sealing mechanism encloses the gap in pool wall sleeve.The slow positron source of pile base can utilize heavy water convection to cool slow positron generating component, effectively improve heat dissipation efficiency, and improve slow positron beam intensity upper limit.

Description

Technical Field

[0001] This invention belongs to the field of nuclear technology, specifically relating to a reactor-based slow positron source, control method, and reactor. Background Technology

[0002] Positron beam detection technology, especially the detection scheme using slow positron beams as microscopic probes, is widely used in surface physics and materials science for non-destructive testing. It boasts advantages such as high detection accuracy, good safety, and strong environmental adaptability, and has found widespread application in aerospace, nuclear engineering, and the semiconductor industry. Reactor-based slow positron sources offer high beam intensity and good stability, making them the best performing slow positron sources overall. However, existing reactor-based slow positron sources generally suffer from insufficient heat dissipation. Since the beam intensity of a slow positron source is closely related to the neutron fluence rate, a higher neutron fluence results in a stronger slow positron beam, but also higher nuclear heating. Insufficient heat dissipation capacity restricts the development of reactor-based slow positron sources. Therefore, providing a reactor-based slow positron source with optimized heat dissipation is of positive significance for improving the slow positron beam intensity. Summary of the Invention

[0003] The purpose of this invention is to provide a reactor-based slow positron source that improves the heat dissipation capacity of the reactor-based slow positron source. This invention also provides a reactor-based slow positron source control method and a reactor.

[0004] According to one aspect of the present invention, a reactor-based slow positron source is provided, which is disposed in a reactor, wherein the reactor includes a water pool and a heavy water tank, the heavy water tank is disposed within the water pool, a gap exists between the wall of the heavy water tank and the wall of the water pool, the water pool contains light water, and the heavy water tank contains heavy water; the reactor-based slow positron source includes:

[0005] The components include a slow positron generator assembly, an outer sleeve, a heavy water tank sleeve, and a sealing assembly.

[0006] A through-wall sleeve is installed on the wall of the pool.

[0007] The heavy water tank sleeve is integrally connected to the heavy water tank and communicates with the inside of the heavy water tank.

[0008] The outer sleeve extends through the pool wall sleeve and the heavy water tank sleeve into the heavy water tank, so that the end of the outer sleeve is submerged in the heavy water; the slow positron generating component is disposed at the end of the outer sleeve and enclosed within the outer sleeve;

[0009] The sealing assembly includes a heavy water sealing mechanism and a light water sealing mechanism. The heavy water sealing mechanism seals the gap between the heavy water tank sleeve and the outer sleeve; the light water sealing mechanism seals the gap inside the pool wall sleeve.

[0010] This reactor-based slow positron source employs an open heavy water tank casing, allowing the outer sleeve end to be directly immersed in heavy water. The circulating heavy water directly cools the slow positron generator assembly, significantly improving cooling efficiency compared to gas-cooled structures. This allows the slow positron generator assembly to produce higher beam intensities and significantly reduces the risk of material melting. Furthermore, the distance between the positron generator assembly and the reactor core can be adjusted by controlling the length of the outer sleeve, thereby controlling the slow positron beam intensity. A heavy water sealing mechanism isolates and seals the heavy water within the tank, preventing leakage and mixing with the light water.

[0011] Furthermore, in some embodiments, the sealing assembly includes a bellows, which is sleeved outside the outer sleeve and connected to the heavy water tank sleeve and the pool wall sleeve, respectively.

[0012] Furthermore, in some embodiments, flanges are respectively provided at the connection ends of the corrugated pipe and the heavy water tank sleeve, and the flanges of the corrugated pipe and the heavy water tank sleeve are connected to form the heavy water sealing mechanism.

[0013] Furthermore, in some embodiments, an end flange is provided at one end of the corrugated pipe extending to the pool wall sleeve, and a flange is provided at one end of the pool wall sleeve located outside the pool wall and connected to the end flange to form the light water sealing mechanism.

[0014] Furthermore, in some embodiments, the bellows is provided with a helium inlet to allow helium to be filled into the bellows.

[0015] Filling the bellows with helium can improve the cooling effect.

[0016] Furthermore, in some embodiments, the slow positron generation component includes (n,γ) converters, (γ,e+) converters, and moderators arranged sequentially along the axial direction of the outer sleeve, wherein the (n,γ) converters are disposed on the wall at the end of the outer sleeve.

[0017] The (n,γ) converter is placed on the wall at the end of the outer sleeve, so that the heavy water in the heavy water tank can directly carry away the heat generated by the (n,γ) converter, effectively improving the heat dissipation efficiency.

[0018] Furthermore, in some embodiments, the slow positron generation assembly further includes a vacuum cylinder and a beam tube. The vacuum cylinder is disposed inside the outer sleeve, and the beam tube is disposed inside the vacuum cylinder. The (γ,e+) converter and the moderator are disposed inside the vacuum cylinder. The moderator is fixedly disposed at the end of the beam tube, and the (γ,e+) converter and the moderator are connected together.

[0019] Furthermore, in some embodiments, a sealing mechanism is provided between the vacuum cylinder and the pool wall sleeve.

[0020] The sealing mechanism between the vacuum cylinder and the pool wall sleeve can further improve the sealing performance and reduce the risk of leakage of heavy water and light water.

[0021] Furthermore, in some embodiments, the outer sleeve is inclined, wherein the end of the outer sleeve extending into the heavy water tank is the lower end, and the opening height of the pool wall sleeve outside the pool is higher than the top of the heavy water tank.

[0022] The angled outer casing ensures that even in the event of a leak, the light water level will not drop below the safe level, thus ensuring the safety of the reactor.

[0023] According to another embodiment of the present invention, a method for controlling a stack-based slow positron source is provided, for controlling the slow positron beam intensity of the stack-based slow positron source provided in any of the foregoing embodiments, and includes the following steps:

[0024] Adjust the depth to which the outer sleeve is inserted into the heavy water tank to adjust the distance between the slow positron generator assembly and the reactor core.

[0025] According to yet another embodiment of the present invention, a reactor is provided, the reactor including a reactor-based slow positron source, the reactor-based slow positron source being configured as the reactor-based slow positron source provided in any of the foregoing embodiments.

[0026] Furthermore, in some embodiments, the reactor includes a plurality of the reactor-based slow positron sources;

[0027] The outer sleeve in the slow positron source is inclined, wherein the end of the outer sleeve that extends into the heavy water tank is the lower end;

[0028] The outer sleeves of the multiple stack-based slow positron sources have different tilt angles. Attached Figure Description

[0029] Figure 1 This is a schematic diagram illustrating the working principle of a reactor-based slow positron source.

[0030] Figure 2 This is a schematic diagram of a stack-based slow positron source structure in one embodiment;

[0031] Figure 3 This is a schematic diagram of a pair of scaled-down slow positron source structures.

[0032] Meaning of the reference numerals in the attached figures:

[0033] 1-(n,γ) converter; 2-(γ,e+) converter; 3-moderater; 4-beam tube; 5-vacuum cylinder; 6-coil; 7-outer sleeve; 8-heavy water tank sleeve; 9-bellows; 10-pool wall sleeve; 11-heavy water tank sleeve flange; 12-bellows front flange; 13-bellows stepped flange; 14-outer sleeve flange; 15-pool wall sleeve flange; 16-bellows rear flange; 17-vacuum cylinder sealing flange; 18-vacuum cylinder helium inlet; 19-vacuum cylinder helium outlet; 20-bellows helium inlet; 21-bellows helium outlet; 22-heavy water tank; 23-pool; 24-pool wall.

[0034] The purpose of the above-described drawings is to provide a detailed description of the present invention so that those skilled in the art can understand the technical concept of the invention, and is not intended to limit the invention. For the sake of brevity, the above-described drawings only schematically depict the structures related to the technical features of the present invention, and do not depict the complete structure and all details strictly according to actual scale. Detailed Implementation

[0035] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0036] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment herein. The phrase appearing in various places in the specification does not necessarily refer to the same embodiment, nor is it limited to mutually exclusive, independent, or alternative embodiments. Those skilled in the art will understand that the embodiments herein can be combined with other embodiments without causing structural conflicts.

[0037] In this description, unless otherwise explicitly specified and limited, the technical terms "installation," "connection," "joining," etc., should be interpreted broadly, for example, referring to movable connections, fixed connections, or integration. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0038] In this description, terms such as "upper," "lower," "left," "right," "lateral," "longitudinal," "height," "length," and "width," which indicate orientation or positional relationships, are intended to accurately describe the embodiments and simplify the description, rather than limiting the parts or structures involved to have a specific orientation, or to be installed or operated in a specific orientation, and should not be construed as limiting the embodiments in this document.

[0039] In this description, terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating relative importance or limiting the number, specific order, or primary / secondary relationship of the described technical features. In this description, "multiple" means at least two.

[0040] Positrons are the antimatter particles of electrons. When incident on matter, they annihilate with electrons within the matter. Utilizing this annihilation property, accurate characterization of microscopic defects and structures in materials can be achieved. This allows for the acquisition of information on elemental types and distributions within defects, as well as structural characteristics. It can also characterize the spatial distribution of materials from the surface to their interior. Currently, positron beams, as microscopic probes for probing material surfaces, are widely used in surface physics, materials science, aerospace, nuclear, and semiconductor industries. In practical applications, the penetration depth of high-energy positrons (hundreds of keV to MeV) is difficult to control, making it impossible to perform layer-by-layer analysis of material surfaces, interfaces, or thin film structures. Therefore, slow positron detection technology with energies in the eV-keV range has found wider application.

[0041] Slow positron sources mainly fall into three categories: those based on radioactive isotopes, those based on accelerators, and those based on reactors. These generate slow positrons through high-energy gamma-ray bombardment by radioactive isotopes, high-energy electron bombardment by electron accelerators, and neutron bombardment by reactors, respectively. Currently, with the development of surface physics and thin film materials, the demand for high-precision characterization of the microstructure of material surfaces in polymer or semiconductor thin film materials based on films is placing increasingly higher demands on the beam intensity and energy monochromaticity of slow positron beams. Among the three types of slow positron sources, reactor-based slow positron sources (reactor-based slow positron sources) can achieve a positron beam intensity of up to 10-1. 8 -10 9 The e+ / s ratio is far higher than that of radioactive isotope sources, and the continuity and stability of the beam output are significantly better than those of accelerator sources, thus it has the best application prospects.

[0042] The basic principle of a stacked slow positron source is as follows: Figure 1 As shown, neutrons generated in the reactor core bombard the (n,γ) converter, producing gamma-ray photons. These gamma-ray photons then bombard the (γ,e+) converter, producing positrons. The positrons subsequently enter the moderator, undergoing inelastic collisions and losing energy, becoming moderated, and are then extracted to form a slow positron beam. During reactor-based slow positron generation, both neutrons and gamma-ray photons deposit energy on the converters. Particularly on the (n,γ) converter, the absorption of neutrons and the release of gamma-ray photons release a significant amount of energy, which is deposited on the (n,γ) converter, constituting the majority of the energy deposition in the generator. Therefore, the design must consider appropriate heat dissipation measures for the (n,γ) converter to ensure that the temperature of the generator does not exceed the material critical values ​​and safety limits.

[0043] Currently, conventional stack-based slow positron source structures, such as Figure 3As shown, the reactor is equipped with channels to accommodate a slow positron source. Specifically, the reactor pool 23 contains a heavy water tank 22, which is filled with light water and submerges the heavy water tank 22. The heavy water tank 22 contains the reactor core. Horizontal channels are provided on the pool wall 24 and the wall of the heavy water tank 22 to accommodate the slow positron source equipment. The channels of the heavy water tank 22 are equipped with a heavy water tank sleeve 8 that is closed at the end, and the channels of the pool wall 24 are equipped with a pool wall sleeve 10. A corrugated pipe 9 connects the heavy water tank sleeve 8 and the pool wall sleeve 10. The heavy water tank sleeve flange 11 at the end of the heavy water tank sleeve 8 is connected to the front flange 12 of the corrugated pipe, and the rear flange 16 of the corrugated pipe is connected to the pool wall sleeve flange 15, forming a sealed structure that isolates the heavy water and light water outside the channels. The outer casing 7 and the vacuum cylinder 5, which passes through the outer casing, extend through the pool wall sleeve 10 and the corrugated pipe 9 to the end of the heavy water tank sleeve 8. The slow positron generation assembly is located inside the vacuum cylinder 5, specifically including a beam tube 4 extending from outside the reactor, and (n,γ) converter 1, (γ,e+) converter 2, and moderator 3 arranged in series along the axial direction at the end of the beam tube 4. The (n,γ) converter 1 is located at the very end of the series structure. The slow positron beam exits the reactor along the beam tube 4 and is then guided out by the coil 6. During the operation of the slow positron source, neutrons, γ photons, etc., mainly generate nuclear heating on the converter and moderator 3. The end of the vacuum cylinder 5 is provided with a vacuum cylinder sealing flange 17, which is connected to the rear flange 16 of the bellows to form a seal. The vacuum cylinder sealing flange 17 is provided with a vacuum cylinder helium inlet 18 and a vacuum cylinder helium outlet 19, which can form a helium flow in the chamber between the vacuum cylinder 5 and the outer sleeve 7. The heat generated by the converter and the moderator 3 is transferred to the vacuum cylinder through thermal radiation and then dissipated through the convection of the flowing helium.

[0044] The beam intensity of a reactor-based slow positron source depends on the neutron fluence of the reactor core. Increasing the neutron fluence leads to higher nuclear heat generation. When further increasing the slow positron beam intensity is required, helium cooling is insufficient to remove the nuclear heat. Excessive heat deposition can cause the material temperature to exceed a critical value, resulting in equipment failure or even material melting. Therefore, heat dissipation capacity is limiting the application of reactor-based slow positron sources.

[0045] However, since the main body of the slow positron source is located inside the reactor, space is limited, and additional cooling devices would significantly increase system complexity and development costs. Introducing new cooling devices into the reactor core may also lead to a decrease in system reliability.

[0046] To address the aforementioned problems, one embodiment of the present invention provides a stack-based slow positron source with improved cooling performance. The structure of this stack-based slow positron source is as follows: Figure 2 As shown:

[0047] The reactor-based slow positron source includes a slow positron generating assembly, an outer sleeve 7, a heavy water tank sleeve 8, and a sealing assembly. A through-wall sleeve 10 is installed on the pool wall 24. The heavy water tank sleeve 8 is welded integrally to the wall of the heavy water tank 22, with its end open and connected to the inside of the heavy water tank 22. The outer sleeve 7 extends through the pool wall sleeve 10 and the heavy water tank sleeve 8 installed on the pool wall 24 of the pool 23 into the heavy water tank 22, so that its end is submerged in heavy water. The slow positron generating assembly is located at the end of the outer sleeve 7 and is enclosed within the outer sleeve 7.

[0048] The slow positron generation assembly includes (n,γ) converter 1, (γ,e+) converter 2 and moderator 3 arranged sequentially along the axial direction of the outer sleeve 7. The (n,γ) converter 1 is located on the inner wall of the end of the outer sleeve 7, so that the heavy water in the heavy water tank 22 can directly carry away the heat generated by the (n,γ) converter 1 through convection heat transfer, thereby effectively improving the heat dissipation efficiency.

[0049] The vacuum cylinder 5 is installed inside the outer sleeve 7, and the beam tube is installed inside the vacuum cylinder. The (γ,e+) converter 2 and the moderator 3 are installed inside the vacuum cylinder. The moderator 3 is fixedly installed at the end of the beam tube 4, and the (γ,e+) converter 2 and the moderator 3 are connected together. The heat generated by the (γ,e+) converter 2 and the moderator 3 is transferred to the wall of the vacuum cylinder 5 through radiation heat transfer. The space between the vacuum cylinder 5 and the outer sleeve 7 is filled with flowing helium gas, which can remove the heat from the wall of the vacuum cylinder 5 through convection heat transfer, thus achieving a heat dissipation effect.

[0050] The sealing assembly includes a heavy water sealing mechanism and a light water sealing mechanism. The heavy water sealing mechanism seals the gap between the heavy water tank sleeve 8 and the outer sleeve 7 to prevent heavy water leakage from the heavy water tank 22. The light water sealing mechanism seals the gap within the pool wall sleeve 10 to prevent light water leakage from the pool 23. Specifically, the sealing assembly includes a bellows 9, one end of which is connected to the heavy water tank sleeve 8, and the other end is connected to the port of the pool wall sleeve 10 located on the outer surface of the pool wall 24, forming seals respectively. The heavy water tank sleeve flange 11 is connected to the corrugated pipe front flange 12 to form a heavy water sealing mechanism, which seals the heavy water in the heavy water tank 22, preventing the heavy water from passing through the sealing surface formed by the heavy water tank sleeve flange 11 and the corrugated pipe front flange 12. The corrugated pipe 9 extends to the end of the pool wall sleeve 10 and is provided with a corrugated pipe rear flange 16. The end of the pool wall sleeve 10 located outside the pool wall 24 is provided with a pool wall sleeve flange 15. The pool wall sleeve flange 15 is connected to the corrugated pipe rear flange 16 to form a light water sealing mechanism, preventing the light water in the pool 23 from passing through the sealing surface formed by the pool wall sleeve flange 15 and the corrugated pipe rear flange 16. A vacuum cylinder sealing flange 17 is provided at the end of the vacuum cylinder 5. The vacuum cylinder sealing flange 17 overlaps and connects with the bellows rear flange 16 and the pool wall sleeve flange 15 to form a double seal. On the one hand, this further improves the sealing effect on light water, and on the other hand, it forms a closed chamber between the vacuum cylinder 5 and the outer sleeve 7. The vacuum cylinder sealing flange 17 is provided with a vacuum cylinder helium inlet 18 and a vacuum cylinder helium outlet 19. Helium can flow in from the vacuum cylinder helium inlet 18 and flow out from the vacuum cylinder helium outlet 19, forming a helium flow between the vacuum cylinder 5 and the outer sleeve 7 to achieve convective heat dissipation. Furthermore, the bellows 9 is also provided with a bellows helium inlet 20 and a bellows helium outlet 21. Helium flows in from the bellows helium inlet 20 and flows out from the bellows helium outlet 21 to form a helium flow between the outer sleeve 7 and the bellows 9, further improving the convective heat dissipation effect.

[0051] In a preferred embodiment, the pool wall sleeve 10, the corrugated pipe 9, the heavy water tank sleeve 8, and the outer sleeve 7 passing through them are all inclined, so that the end of the outer sleeve 7 is the lower end. The opening height of the pool wall sleeve 10 outside the pool 23 is higher than the top of the heavy water tank 22. The inclined design can further improve the safety of the reactor. Even if a seal failure occurs and leakage occurs, it can ensure that the light water in the pool 23 is at a safe level and prevent the accident from worsening.

[0052] The installation method of the above-mentioned slow positron source is as follows: When building the reactor, corresponding channels need to be reserved on the heavy water tank 22 and the pool wall 24, and the heavy water tank sleeve 8 is welded and the pool wall sleeve 10 is buried. The corrugated pipe 9 is installed when the heavy water and light water of the reactor are drained. Then, the outer sleeve 7 and its internal components are inserted through the opening of the pool wall sleeve 10 and the assembly is completed.

[0053] After the reactor starts operating, neutrons generated in the core bombard (n,γ) converter 1 through the wall of the outer casing 7 to produce γ photons. The energy deposited on the (n,γ) converter 1 is transferred to the outer casing 7 through contact heat transfer and carried away by the heavy water in the heavy water tank 22. The γ photons pass through the wall of the vacuum tube 5 to bombard (γ,e+) converter 2 to produce positrons. The positrons enter the moderator 3 and are slowed down to slow positrons. The slow positrons are emitted from the core along the beam tube 4 and form a slow positron beam output under the guidance of the electromagnetic field generated by the coil 6 and other equipment. The heat generated by the (γ,e+) converter 2 and the moderator 3 is carried away by the helium flow.

[0054] The reactor-based slow positron source provided in the above embodiments uses heavy water for direct convective cooling of the front end of the outer casing 7, effectively improving the heat dissipation capacity of the converter and moderator, especially the heat dissipation capacity of the (n,γ) converter 1 which withstands neutron bombardment from the reactor core. Due to the improved cooling performance, the (n,γ) converter 1 can withstand a higher neutron flux rate, thus enabling the reactor-based slow positron source to output a slow positron beam with a higher beam intensity. Simultaneously, the tilted design effectively improves the inherent safety of the reactor and reduces the risk of coolant leakage. This reactor-based slow positron source has a simple structure, effectively improving heat dissipation without introducing complex new structures. It is easy to install and maintain, and converter replacement and other tasks can be completed outside the reactor.

[0055] Based on this slow positron source design, another embodiment of the present invention provides a reactor-based slow positron source control method. By adjusting the depth of the outer sleeve 7 inserted into the heavy water tank 22 (for example, by replacing the outer sleeve 7 with one of different lengths), the distance between the slow positron generating component and the reactor core is adjusted, thereby adjusting the neutron flux rate of the (n,γ) converter 1 and thus adjusting the slow positron beam intensity.

[0056] In another aspect of the present invention, a reactor is provided that employs the reactor-based slow positron source provided in the foregoing embodiments. In a preferred embodiment, the reactor is configured with a plurality of reactor-based slow positron sources, the outer casings of which are inserted into the heavy water tank 22 at different tilt angles.

[0057] The purpose of the above embodiments is to provide a further detailed description of the present invention in conjunction with the accompanying drawings, so that those skilled in the art can understand the technical concept of the present invention. Within the scope of the present invention, optimizations or equivalent substitutions of the involved structures or method steps, as well as combinations of implementation methods in different embodiments without causing structural or principle conflicts, all fall within the protection scope of the present invention.

Claims

1. A reactor-based slow positron source, disposed in a reactor, wherein the reactor includes a water pool and a heavy water tank, the heavy water tank being disposed within the water pool, a gap existing between the wall of the heavy water tank and the wall of the water pool, the water pool containing light water, and the heavy water tank containing heavy water; characterized in that, include: The components include a slow positron generator assembly, an outer sleeve, a heavy water tank sleeve, and a sealing assembly. A through-wall sleeve is installed on the wall of the pool. The heavy water tank sleeve is integrally connected to the heavy water tank and communicates with the inside of the heavy water tank. The outer sleeve extends through the pool wall sleeve and the heavy water tank sleeve into the heavy water tank, so that the end of the outer sleeve is submerged in the heavy water; the slow positron generating component is disposed at the end of the outer sleeve and enclosed within the outer sleeve; The sealing assembly includes a heavy water sealing mechanism and a light water sealing mechanism. The heavy water sealing mechanism seals the gap between the heavy water tank sleeve and the outer sleeve; the light water sealing mechanism seals the gap inside the pool wall sleeve.

2. The stack-based slow positron source according to claim 1, characterized in that, The sealing assembly includes a bellows, which is sleeved outside the outer sleeve and connected to the heavy water tank sleeve and the pool wall sleeve, respectively.

3. The stack-based slow positron source according to claim 2, characterized in that, The corrugated pipe is connected to the heavy water tank sleeve at the end of the heavy water tank sleeve outside the water pool. Flanges are provided at the connection points, and the flanges of the corrugated pipe and the heavy water tank sleeve are connected to form the heavy water sealing mechanism.

4. The stack-based slow positron source according to claim 2 or 3, characterized in that, The corrugated pipe extends to one end of the pool wall sleeve and is provided with an end flange. The end of the pool wall sleeve located on the outside of the pool wall is provided with a flange and is connected to the end flange to form the light water sealing mechanism.

5. The stack-based slow positron source according to claim 1, 2, or 3, characterized in that, The bellows is provided with a helium inlet to allow helium to be filled into the bellows.

6. The stack-based slow positron source according to claim 1, 2, or 3, characterized in that, The slow positron generation assembly includes (n,γ) converters, (γ,e+) converters, and moderators arranged sequentially along the axial direction of the outer sleeve, with the (n,γ) converters disposed on the wall at the end of the outer sleeve.

7. The stack-based slow positron source according to claim 6, characterized in that, The slow positron generation assembly also includes a vacuum cylinder and a beam tube. The vacuum cylinder is inserted inside the outer sleeve, and the beam tube is inserted inside the vacuum cylinder. The (γ,e+) converter and the moderator are disposed inside the vacuum cylinder. The moderator is fixedly disposed at the end of the beam tube, and the (γ,e+) converter and the moderator are connected together.

8. The stack-based slow positron source according to claim 7, characterized in that, A sealing mechanism is provided between the vacuum cylinder and the pool wall sleeve.

9. The stack-based slow positron source according to claim 1, 2, or 3, characterized in that, The outer sleeve is inclined, wherein the end of the outer sleeve extending into the heavy water tank is the lower end, and the opening height of the pool wall sleeve outside the pool is higher than the top of the heavy water tank.

10. A method for controlling a reactor-based slow positron source, characterized in that, For controlling the slow positron beam intensity of the stack-based slow positron source as described in any one of claims 1 to 9, and comprising the following steps: Adjust the depth to which the outer sleeve is inserted into the heavy water tank to adjust the distance between the slow positron generator assembly and the reactor core.

11. A reactor, characterized in that, The reactor includes a reactor-based slow positron source, which is configured as a reactor-based slow positron source as described in any one of claims 1 to 9.

12. The reactor according to claim 11, characterized in that, The reactor includes multiple reactor-based slow positron sources; The outer sleeve in the slow positron source is inclined, wherein the end of the outer sleeve that extends into the heavy water tank is the lower end; The outer sleeves of the multiple stack-based slow positron sources have different tilt angles.

Images