A neutron emission device with controllable neutron flux

Abstract

The present invention discloses a neutron emission device with controllable neutron flux, comprising a device body, wherein the device body is provided with an exit channel, a silo is provided in the device body, the exit channel is provided on a side away from the silo, a neutron source is provided in the silo, and a driving mechanism for driving the neutron source to move in the extension direction of the silo is provided in the silo. The staff drives the driving mechanism to change the position of the neutron source in the silo. When the neutron source is at a deeper position in the silo, the opening angle of the neutron source to the inlet of the silo is smaller, and the path to the exit channel becomes longer, thereby increasing the neutron decay time. By controlling the position of the neutron source in the silo, the time for the neutron to reach the exit channel is adjusted, and then the number of neutrons reaching the exit channel is changed, so as to achieve the effect of controlling the neutron flux at the channel mouth of the exit channel.

Description

Technical Field

[0001] The invention relates to the field of nuclear technology and applications, in particular to a neutron emission device with controllable neutron flux. Background Art

[0002] Neutron sources are widely used in both military and civilian fields. Commonly used neutron sources include accelerator neutron sources, fission neutron sources, dense plasma focus neutron sources and isotope neutron sources.

[0003] The first three types of neutron sources are controllable neutron sources, among which accelerator neutron sources and fission neutron sources have high neutron flux and high safety, but their devices are huge and cannot be moved, so they are only suitable for fixed positions. Although the dense plasma focus neutron source is controllable, it belongs to the pulsed intermittent working mode, and the stability of this type of neutron source is poor, so the application of this type of neutron source in the field of precise measurement is greatly limited.

[0004] Isotope neutron sources produce neutrons by using a nuclear reaction between two nuclides or by using the fission of the nuclides themselves. Currently used sources include Am-Be sources, Pu-Be sources, Ra-Be sources and Cf spontaneous fission neutron sources.

[0005] Currently, the isotope neutron source devices on the market do not have a neutron flux control link. In an environment where the demand for precision control of neutron flux in neutron beam devices for neutron activation or material surface property research is increasingly high, the current emission source devices need to replace different neutron sources to obtain neutron beams with different neutron fluxes. This method is more troublesome to control the neutron flux size. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a neutron emission device with controllable neutron flux, which is relatively simple to control the neutron flux.

[0007] The solution of the present invention to solve its technical problem is:

[0008] A neutron emission device with controllable neutron flux comprises a device body, wherein the device body is provided with an emission channel, a launch silo is provided in the device body, the emission channel is provided on a side away from the launch silo, a neutron source is provided in the launch silo, and a driving mechanism for driving the neutron source to move in the extension direction of the launch silo is provided in the launch silo.

[0009] As a further improvement of the above technical solution, the device body is configured to be made of neutron absorbing material.

[0010] As a further improvement of the above technical solution, a moderator layer is fixedly connected to the inner wall of the device body.

[0011] As a further improvement of the above technical solution, a support plate is provided between the pushing device and the neutron source, and the outer peripheral surface of the support plate abuts against the inner wall of the moderator layer in the launch shaft.

[0012] As a further improvement of the above technical solution, the cross-sections of the launch shaft and the support plate are both set to be circular, and the neutron source is set at the center of the launch shaft.

[0013] As a further improvement of the above technical solution, a telescopic guide rod is arranged between the support plate and the bottom surface of the silo, and the telescopic guide rod includes a telescopic sleeve and a telescopic rod. The telescopic rod sleeve is arranged in the telescopic sleeve, and the telescopic rod slides in the telescopic sleeve. The two ends of the telescopic sleeve away from the telescopic rod are respectively fixedly connected to the support plate and the bottom surface of the silo, and the extension direction of the telescopic sleeve and the telescopic rod is perpendicular to the bottom surface of the silo.

[0014] As a further improvement of the above technical solution, a through hole is opened at the bottom of the launching silo, and the pushing device includes a push rod, one end of which is connected to the support plate, and the other end is threadedly connected to the through hole.

[0015] As a further improvement of the above technical solution, a limit ring protrudes outward from one end of the push rod close to the support plate, and a connecting block protrudes toward the push rod from the support plate. The connecting block is provided with a rotating cavity, and the end of the push rod close to the support plate and the limit ring rotate in the rotating cavity, and the end of the push rod away from the support plate is fixedly connected to a driving mechanism for driving the push rod to rotate along its central axis.

[0016] As a further improvement of the above technical solution, the driving mechanism is configured as a hand wheel.

[0017] As a further improvement of the above technical solution, the central axis of the exit channel and the central axis of the launch shaft are arranged perpendicular to each other.

[0018] The beneficial effect of the present invention is that the staff drives the pushing mechanism to change the position of the neutron source in the launch shaft. When the neutron source is at a deeper position in the launch shaft, the opening angle of the neutron source to the launch shaft entrance becomes smaller, and the path between reaching the exit channel becomes longer, thereby increasing the neutron decay time. By controlling the position of the neutron source in the launch shaft, the time for the neutrons to reach the exit channel is adjusted, and then the number of neutrons reaching the exit channel is changed, so as to achieve the effect of controlling the neutron flux at the channel mouth of the exit channel.

[0019] The invention is used in the field of nuclear technology and applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly describes the drawings required for use in the description of the embodiments. Obviously, the drawings described are only part of the embodiments of the present invention, not all of the embodiments, and those skilled in the art can also obtain other design solutions and drawings based on these drawings without creative work.

[0021] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0022] In the figure, 1. device body; 11. support foot; 12. exit channel; 13. launch silo; 14. neutron shielding cover; 15. moderator; 2. neutron source; 3. support plate; 31. connecting block; 32. rotating cavity; 4. pushing device; 41. push rod; 411. limit ring; 42. hand wheel; 5. telescopic guide rod; 51. telescopic sleeve; 52. telescopic rod. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the concept, specific structure and technical effects of the present invention in combination with the embodiments and drawings, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by technicians in this field without creative work are all within the scope of protection of the present invention. In addition, all the connection / connection relationships mentioned in the text do not refer to the direct connection of components, but refer to the formation of a better connection structure by adding or reducing connection accessories according to the specific implementation situation. The various technical features in the invention can be combined interchangeably without conflicting with each other.

[0024] Reference Figure 1 , a neutron flux controllable emission device, comprising a device body 1 and a neutron source 2. Four legs 11 are fixedly connected to the lower end of the device body 1, and the four legs 11 are distributed in a rectangular array, and the four legs 11 support the device body 1. The neutron source 2 is arranged inside the device body 1. The material of the device body 1 is set to boron steel material, which can absorb neutrons, reduce the radiation of the emission device, and reduce the harm of the emission device to the staff. Three exit channels 12 are opened on the device body 1. When some of the exit channels 12 are not in use, a neutron shielding cover 14 is detachably fixedly connected to the exit port of the exit channel 12, and the exit port of the unused exit channel 12 is closed to prevent neutrons from being emitted from the unused exit channel 12 and affecting the surrounding environment.

[0025] The inner wall of the device body 1 is fixedly connected with a moderator layer 15, which is mainly made of polyethylene. After the neutron source 2 emits neutrons, the neutrons will contact the moderator layer 15. The more the neutrons contact the moderator layer 15, the longer it takes for them to be ionized to the exit channel 12, thereby increasing the decay time of the neutrons, and the number of neutrons in the device body 1 decays according to the decay formula.

[0026] A launch shaft 13 is provided at the lower part of the device body 1. The cross section of the launch shaft 13 is set to be circular. The neutron source 2 is set in the launch shaft 13 and at the center of the launch shaft 13. The circular launch shaft 13 makes the neutrons emitted by the neutron source 2 reach the inner wall of the same height of the launch shaft 13 at the same time. The central axis of the launch shaft 13 is perpendicular to the central axis of the exit channel 12. Through such a setting, the neutrons emitted by the neutron source 2 cannot directly reach the exit channel 12, but need to contact with the moderator layer 15 for multiple times before entering the exit channel 12, thereby reducing the energy of the emitted neutrons and making the nuclear reaction easy to proceed and stable.

[0027] A support plate 3 and a pushing device 4 are provided in the launch silo 13. A through hole is provided at the bottom of the launch silo 13, and the pushing device 4 includes a push rod 41 and a hand wheel 42. The end of the push rod 41 away from the support plate 3 is threadedly connected to the through hole. The hand wheel 42 is fixedly connected to the end of the push rod 41 away from the support plate 3. The staff drives the push rod 41 to rotate relative to the device body 1 by turning the hand wheel 42. Since the push rod 41 is threadedly connected to the through hole, when the hand wheel 42 is turned, the push rod 41 will be displaced in the axial direction of the launch silo 13, so that the height of the neutron source 2 in the launch silo 13 changes, so that the number of contacts between the emitted neutrons and the moderator layer 15 changes, and then the neutron flux at the exit port of the exit channel 12 is controlled.

[0028] A telescopic guide rod 5 is provided between the support plate 3 and the bottom of the launch shaft 13, and the telescopic guide rod 5 includes a telescopic sleeve 51 and a telescopic rod 52. The telescopic sleeve 51 is fixedly connected to the bottom of the launch shaft 13, and the telescopic rod 52 is fixedly connected to the surface of the support plate 3 near the bottom of the launch shaft 13. The telescopic rod 52 is sleeved in the telescopic sleeve 51 and is slidably connected to the telescopic sleeve 51. The extension directions of the telescopic sleeve 51 and the telescopic rod 52 are perpendicular to the telescopic guide rod 5, which guide the support plate 3 so that the support plate 3 can only be displaced in the height direction of the launch shaft 13, and the telescopic sleeve 51 and the telescopic rod 52 limit the rotation of the support plate 3, so as to prevent the support plate 3 from rotating with the rotation of the push rod 41, thereby affecting the normal operation of the neutron source 2.

[0029] The end of the push rod 41 close to the support plate 3 has a limit ring 411 protruding outward. The surface of the support plate 3 close to the push rod 41 has a connection block 31 protruding, and the connection block 31 has a rotation cavity 32. The end of the push rod 41 close to the support plate 3 and the limit ring 411 are arranged in the rotation cavity 32, and the push rod 41 and the limit ring 411 are both rotatably connected to the rotation cavity 32. The cooperation of the limit ring 411 and the connection block 31 enables the support plate 3 to rise or fall with the push rod 41, so as to avoid the support plate 3 being unable to fall due to excessive friction between other components when the push rod 41 falls, thereby affecting the emission device's regulation of the neutron flux at the exit port of the exit channel 12.

[0030] The implementation principle of this embodiment is as follows: when it is necessary to increase the neutron flux at the exit port of the exit channel 12, the hand wheel 42 is turned to move the neutron source 2 upward. After the neutron source 2 is moved upward, the number of contacts between the neutrons emitted by the neutron source 2 and the moderator layer 15 is reduced, and the path to the exit channel 12 is shortened, thereby reducing the neutron decay time; when it is necessary to reduce the neutron flux at the exit port of the exit channel 12, the hand wheel 42 is turned to move the neutron source 2 downward. After the neutron source 2 is moved downward, the number of contacts between the neutrons emitted by the neutron source 2 and the moderator layer 15 is increased, and the path to the exit channel 12 is increased, thereby increasing the neutron decay time.

[0031] The preferred embodiments of the present invention are specifically described above, but the invention is not limited to the embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A neutron emission device with controllable neutron flux, characterized in that: The device comprises a device body (1), the device body (1) being provided with an exit channel (12), a launch shaft (13) being provided in the device body (1), the exit channel (12) being provided on a side away from the launch shaft (13), a neutron source (2) being provided in the launch shaft (13), and a driving mechanism for driving the neutron source (2) to move in an extension direction of the launch shaft (13); The device body (1) is made of neutron absorbing material; A moderator layer (15) is fixedly connected to the inner wall of the device body (1); A support plate (3) is provided between the pushing mechanism and the neutron source (2), and the outer peripheral surface of the support plate (3) abuts against the inner wall of the moderator layer (15) in the launch shaft (13); The cross-sections of the launch shaft (13) and the support plate (3) are both arranged to be circular, and the neutron source (2) is arranged at the center of the launch shaft (13); A telescopic guide rod (5) is arranged between the support plate (3) and the bottom surface of the launch silo (13), and the telescopic guide rod (5) comprises a telescopic sleeve (51) and a telescopic rod (52). The telescopic rod (52) is sleeved in the telescopic sleeve (51), and the telescopic rod (52) slides in the telescopic sleeve (51). The two ends of the telescopic sleeve (51) and the telescopic rod (52) that are away from each other are fixedly connected to the support plate (3) and the bottom surface of the launch silo (13), respectively. The extension direction of the telescopic sleeve (51) and the telescopic rod (52) is perpendicular to the bottom surface of the launch silo (13).

2. A neutron emission device with controllable neutron flux according to claim 1, characterized in that: A through hole is provided at the bottom of the launch silo (13), and the pushing mechanism comprises a push rod (41), one end of the push rod (41) is connected to the support plate (3), and the other end is threadedly connected to the through hole.

3. A neutron emission device with controllable neutron flux according to claim 2, characterized in that: The end of the push rod (41) close to the support plate (3) has a limit ring (411) protruding toward the outside of the push rod (41); the support plate (3) has a connecting block (31) protruding toward the push rod (41); the connecting block (31) is provided with a rotating cavity (32); the end of the push rod (41) close to the support plate (3) and the limit ring (411) rotate in the rotating cavity (32); the end of the push rod (41) away from the support plate (3) is fixedly connected to a driving component for driving the push rod (41) to rotate along its central axis.

4. A neutron emission device with controllable neutron flux according to claim 3, characterized in that: The driving component is configured as a hand wheel (42).

5. The neutron emission device with controllable neutron flux according to claim 1, characterized in that: The central axis of the exit channel (12) and the central axis of the launch shaft (13) are arranged perpendicular to each other.

Images