A moving target for neutron generation

Abstract

The present invention provides a mobile target for neutron generation, the mobile target comprising a vacuum cavity, a mobile device and a target body installed in the vacuum cavity, the mobile device being installed on the top inner wall of the vacuum cavity, the target body being detachably installed on the mobile device through a hook assembly, and the mobile device being capable of controlling the reciprocating motion of the target body. The present invention solves the problem of high local heat caused by beam concentration of the existing static target by using a mobile device to control the left and right reciprocating motion of the target body, effectively reduces the heat deposition per unit volume of the target body, and also reduces the peak value of the heat concentration of the target body, thereby reducing the requirements for the proton beam.

Description

Technical Field

[0001] The present invention relates to the technical field of neutron therapy, and in particular to a neutron generation mobile target for a BNCT device. Background Art

[0002] In cancer treatment, radiation therapy is highly valued, and neutron capture therapy (BNCT) is particularly noteworthy for its potential for selective treatment at the cellular level in principle. In BNCT, stable isotopes with a high capture cross section for neutrons are introduced into cancer cells in advance, and neutrons react with them to produce heavy ions with a short range and high LET (Linear Energy Transfer), which kill cancer cells while having little effect on normal cells. Currently, BNCT uses B, Gd and thermal neutrons or epithermal neutrons for cancer treatment.

[0003] In recent years, neutron generators that accelerate protons to a specified energy and irradiate specific targets to generate neutrons have attracted attention because they can be used in hospitals. Neutron generators based on accelerators are simple in equipment and have low operating costs, and are the future development direction. Generally, the targets of neutron generators for this purpose are mainly "lithium using the Li(p, n)Be reaction" and "beryllium using the Be(p, n) reaction", but beryllium itself is toxic and has a low neutron yield, requiring higher accelerator energy, and due to the low melting point and thermal conductivity of lithium, it has extremely high requirements for heat dissipation.

[0004] In order to solve the difficult problem of rapid heat dissipation of the target material, people have come up with some solutions during the research and development process. For example, U.S. Patent US20100067640A1 discloses a high energy density lithium target, which adopts a conical target body and has a design power of 50kW. However, the conical target body of the patent needs to adopt an annular beam spot, and the Gaussian beam spot needs to be converted into an annular beam spot, which has very high requirements for the accelerator and increases the beam loss. In addition, the cooling effect of the cooling medium at the top of the cone is poor, and cavitation is easily formed at the top of the cone, which is not conducive to the stable operation of the target body. Another example is a target for a neutron generation device and a manufacturing method thereof disclosed in Chinese Patent CN104429168A. Due to its flat static target body, it is necessary to homogenize the proton beam, which increases the accelerator's requirements for proton beam homogenization to a certain extent. In addition, the flat target is also limited by the highest peak of the heat sink. Another example is Taiwan Patent TW201706008A, which discloses a rotating target that can effectively remove heat, but has a complex structure and a large equipment footprint.

[0005] Therefore, we need a method that can disperse the heat deposition inside the target body, reduce the concentrated peak value of the target body heat, and effectively improve the heat dissipation limitations of the planar static target. Therefore, the present invention aims to provide a mobile target for neutron generation. Summary of the invention

[0006] The purpose of the present invention is to provide a mobile target for neutron generation, aiming to solve the problems in the prior art that beryllium itself is toxic, brittle, and has poor machining performance, the use of neutron generation targets using beryllium as the target material is limited, the neutron yield is lower than that of lithium, the accelerator energy and power required for treatment are high, and the device cost is high; it also solves the problem that the planar static target in the prior art needs to homogenize the proton beam to reduce the maximum heat flux density, and the heat is concentrated and difficult to dissipate; and it also solves the problem that the conical and wedge-shaped target bodies in the prior art reduce the heat flux density per unit area, but the requirements for the accelerator are very high and the beam loss is also increased; in addition, it also solves the problem that the rotating target in the prior art has a complex structure, a large equipment size, is not conducive to coupling with a moderator, has a low neutron utilization efficiency, is difficult to install and operate, and has low stability.

[0007] To achieve the above-mentioned purpose, the present invention provides a mobile target for neutron generation, comprising a vacuum chamber and a mobile device and a target body installed in the vacuum chamber, wherein the mobile device is installed on the top inner wall of the vacuum chamber, and the target body is detachably installed on the mobile device through a hook assembly, and the mobile device can control the reciprocating motion of the target body, and the mobile device and the target body are arranged vertically.

[0008] Further preferably, the moving device includes a linear guide screw device and a stepper motor, which are both arranged above the target body, and the linear guide screw device is installed on the top inner wall of the vacuum chamber. One end of the linear guide screw device is connected to the stepper motor. The stepper motor drives the screw to rotate forward and reverse to drive the target body to reciprocate left and right, thereby realizing the deposition of dispersed target heat, which is suitable for a variety of proton beams.

[0009] Further preferably, the hook assembly includes a mounting platform and a hook, wherein the hook is provided with a rectangular protrusion, and the mounting platform is provided with a mounting groove matched with the rectangular protrusion, so that the stress generated on the hook when the target body moves can be shared, and the mounting platform is arranged below the linear guide screw device, and the hook is arranged above the target body, and the target body is detachably mounted on the mounting platform of the linear guide screw device through the hook, which makes it easy to disassemble and replace the target body under vacuum conditions.

[0010] Further preferably, the target body includes a metal substrate and a target body shell, a hook is arranged above the target body shell, and the target body shell is detachably mounted on the mounting table of the linear guide screw device through the hook, and the target body can be replaced directly by operating the hook.

[0011] Further preferably, a target material filling groove is provided on the front side of the metal substrate, the front side is the side facing the proton beam, and the back side is the side facing away from the proton beam. The target material filling groove is used to fill the target material and seal the metal film, and its length, width and depth are 120mm*60mm*1mm. The gap between the back side of the metal substrate and the front side of the target body shell forms a serial water-cooling heat exchange channel for cooling the heat deposited by the target material.

[0012] Further preferably, a plurality of guide plates are provided on the back of the metal substrate, the guide plates are 5 mm high, and a gap groove matching the height of the guide plates is provided on the front of the target shell. The guide plates and the gap grooves form a serial water-cooled heat exchange channel, thereby improving flow stability.

[0013] Further preferably, a working fluid inlet and a working fluid outlet for conveying cooling working fluid are provided on the back of the target body shell, and both the working fluid inlet and the working fluid outlet are connected with bellows to facilitate the movement of the target body, and the working fluid inlet and the working fluid outlet are connected with the serial water cooling heat exchange channel.

[0014] Further preferably, a first pit with a fluid inlet section is provided at the working medium inlet, so as to avoid the problem of local flow unevenness caused by the jet impact of the fluid on the metal substrate; a second pit with a fluid collection section is provided at the working medium outlet to prevent backflow at the outlet and ensure the stability of the flow field; the first pit and the second pit are connected to the serial water-cooled heat exchange channel. Compared with the parallel flow channel, the flow field unevenness will not occur, thereby improving the cooling reliability.

[0015] Further preferably, the target material is sealed in the target material filling groove.

[0016] Further preferably, the target material is sealed in the target material filling groove by hot isostatic pressing through a sealing metal film.

[0017] Further preferably, the metal substrate and the target shell are assembled and connected by bolts passing through the mounting holes, the target shell is 304 stainless steel or nuclear stainless steel, and a rubber gasket is provided between the target shell and the metal substrate.

[0018] The present invention provides a mobile target for neutron generation, which is mainly used for a mobile target for neutron generation in a BNCT device, and has the following beneficial effects:

[0019] 1. By using a mobile device to control the left and right reciprocating motion of the target, the problem of high local heat caused by beam concentration of the existing static target is solved, which effectively reduces the heat deposition per unit volume of the target and also reduces the peak value of target heat concentration, thus reducing the requirements for proton beam current;

[0020] 2. By using a mobile device to control the left and right reciprocating motion of the target, the heat exchange area of ​​the target is increased, the heat dissipation limitation of the target is effectively improved, the heat exchange is enhanced, the risk of target melting is reduced, and the stability of equipment operation is improved;

[0021] 3. Since the target body is directly connected to the mobile device through a hook assembly, it is easy to install and disassemble, thus reducing the cost of replacing the target body;

[0022] 4. It can adapt to different proton beam spots, with less beam loss and low requirements for accelerators;

[0023] 5. By adopting single-phase water-cooled serial flow channels, the flow is uniform, the heat exchange stability is high, and the reliability is strong. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0025] It should be noted that the front side is the side facing the proton beam, while the back side is the side facing away from the proton beam;

[0026] Figure 1 It is a schematic diagram of the front three-dimensional structure of the present invention;

[0027] Figure 2 This is a front perspective structural diagram of the present invention. It is easy for a person skilled in the art to understand that: the moving device is installed on the top inner wall of the vacuum chamber;

[0028] Figure 3 It is a schematic diagram of the front connection structure of the moving device, the hook assembly and the target body of the present invention;

[0029] Figure 4 It is a schematic diagram of the back connection structure of the moving device, the hook assembly and the target body of the present invention;

[0030] Figure 5 It is a schematic diagram of the front exploded structure of the hook assembly and the target body of the present invention;

[0031] Figure 6 It is a structural schematic diagram of the mounting platform of the present invention.

[0032] Among them, the reference numerals in the figure are:

[0033] 1. Moving target; 2. Vacuum chamber;

[0034] 3. Moving device; 31. Linear guide screw device; 32. Stepping motor;

[0035] 4. target body; 41. metal substrate; 411. target material filling groove; 412. mounting hole; 42. target body shell; 421. working fluid inlet; 422. working fluid outlet; 423. first pit; 424. second pit;

[0036] 5. Hook assembly; 51. Mounting platform; 511. Mounting slot; 52. Hook; 521. Rectangular protrusion;

[0037] 6. Serial water cooling heat exchange channel; 61. guide plate; 62. gap groove. DETAILED DESCRIPTION

[0038] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the embodiments of the present invention, and should not be construed as limiting the present invention.

[0039] In the description of the embodiments of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0040] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0041] In the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0042] In one embodiment of the present invention, Figures 1 to 3 As shown, a mobile target 1 for neutron generation is provided, comprising a vacuum chamber 2 and a mobile device 3 and a target body 4 installed in the vacuum chamber 2, wherein the mobile device 3 is installed on the top inner wall of the vacuum chamber 2, and the target body 4 is detachably installed on the mobile device 3 through a hook assembly 5, and the mobile device 3 can control the reciprocating motion of the target body 4, and the mobile device 3 and the target body 4 are arranged vertically.

[0043] Further references Figures 3 to 4 The moving device 3 includes a linear guide screw device 31 and a stepper motor 32. The linear guide screw device 31 and the stepper motor 32 are both arranged above the target body 4. The linear guide screw device 31 is installed on the top inner wall of the vacuum chamber 2. One end of the linear guide screw device 31 is connected to the stepper motor 32. The stepper motor 32 drives the linear guide screw to rotate forward and reverse to drive the target body 4 to reciprocate left and right, thereby realizing the deposition of dispersed heat from the target body 4, which is suitable for a variety of proton beams.

[0044] The hook assembly 5 includes a mounting platform 51 and a hook 52. The mounting platform 51 is arranged below the linear guide screw device 31, and the hook 52 is arranged above the target body 4. The target body 4 is detachably mounted on the mounting platform 51 of the linear guide screw device 31 through the hook 52, so that the target body 4 can be easily disassembled and replaced under vacuum conditions.

[0045] The target body 4 includes a metal substrate 41 and a target body shell 42. The hook 52 is arranged above the target body shell 42. The target body shell 42 is detachably mounted on the mounting table 51 of the linear guide screw device 31 through the hook 52. The target body 4 can be replaced directly by operating the hook 52.

[0046] Among them, Figure 5 The hook 52 shown in FIG. 1 is provided with a rectangular protrusion 521. Figure 6 The mounting platform 51 shown in the figure is provided with a mounting groove 511 matched with the rectangular protrusion 521, so that the stress generated on the hook 52 when the target body 4 moves can be shared.

[0047] Further references Figure 5 It should be noted that the front side is the side facing the proton beam, and the back side is the side facing away from the proton beam.

[0048] It is easy for those skilled in the art to understand that a target material filling groove 411 is provided on the front side of the metal substrate 41, and the target material filling groove 411 is used to fill the target material and seal the metal film, and its length, width and depth are 120mm*60mm*1mm. The gap between the back side of the metal substrate 41 and the front side of the target body shell 42 forms a serial water-cooling heat exchange channel 6 for cooling the heat deposited by the target material.

[0049] Similarly, a plurality of guide plates 61 are provided on the back of the metal substrate 41, and the height of the guide plates 61 is 5 mm. A gap groove 62 matching the height of the guide plates 61 is provided on the front of the target housing 42. The guide plates 61 and the gap groove 62 form a serial water-cooled heat exchange channel 6, which improves the flow stability.

[0050] Next, a working fluid inlet 421 and a working fluid outlet 422 for conveying cooling working fluid are respectively provided on both sides of the lower part of the back side of the target body shell 42. The working fluid inlet 421 and the working fluid outlet 422 are both connected with bellows to facilitate the movement of the target body 4. The working fluid inlet 421 and the working fluid outlet 422 are connected to the serial water-cooling heat exchange channel 6.

[0051] Then, a first pit 423 with a fluid inlet section is provided at the working medium inlet 421 to avoid the problem of local flow unevenness caused by the jet impact of the fluid on the metal substrate. A second pit 424 with a fluid collection section is provided at the working medium outlet 422. The first pit 423 and the second pit 424 are connected to the serial water-cooled heat exchange channel to prevent backflow at the outlet and ensure the stability of the flow field. Compared with parallel flow channels, this method will not cause uneven flow field, thereby improving the reliability of cooling.

[0052] In addition, the target is sealed in the target filling groove 411 .

[0053] Furthermore, the target is sealed in the target filling groove 411 by hot isostatic pressing bonding via a sealing metal film.

[0054] Finally, the metal base plate 41 and the target shell 42 are assembled and connected by bolts passing through the mounting holes 412 . The target shell 42 is made of 304 stainless steel or nuclear stainless steel, and a rubber gasket is provided between the target shell 42 and the metal base plate 41 .

[0055] The second embodiment of the present invention is different from the first embodiment in that the gap groove in the serial water-cooled heat exchange channel is not limited to being set on the front side of the target body shell, but can also be set on the back side of the metal substrate. It only needs to open a gap groove that matches the height of the guide plate on the back side of the metal substrate. The designed wall thickness between the gap groove and the target material filling groove is the same as the wall thickness between the target material filling groove and the gap groove in the first embodiment, and the serial water-cooled heat exchange channel with flow stability and cooling reliability can also be ensured.

[0056] The third embodiment of the present invention is different from the first and second embodiments in that the connection method between the moving device and the linear guide screw device is not limited to the detachable connection between the mounting platform and the hook, but can also be other mutually detachable connection structures, such as a snap connection structure or a pin hole assembly connection, or a mounting hole assembly connection, etc.

[0057] Working principle:

[0058] Run the BNCT device and start the stepper motor 32. Since the target body 4 is detachably mounted on the moving device 3 through the hook assembly 5, the stepper motor 32 drives the forward and reverse rotation of the lead screw to drive the target body 4 to reciprocate left and right. Then, the fluid flows from the working fluid inlet 421 into the first pit 423, passes through the serial water-cooled heat exchange channel 6, and finally flows into the second pit 424 for liquid collection, and flows out through the working fluid outlet 422, which improves the local flow uniformity of the jet impact of the fluid on the metal substrate 41, ensures the flow field stability and cooling reliability, and the working fluid inlet 421 and the working fluid outlet 42 2 is connected with the bellows, which makes it easier to move the target body 4. When the target body 4 needs to be replaced, the BNCT device and the stepper motor 32 are turned off. Only the hook 52 on the target body 4 needs to be removed from the mounting table 51, and the entire target body 4 can be removed under vacuum conditions. Then, after the target body 4 is taken out of the vacuum chamber 2, the bellows of the working fluid inlet 421 and the working fluid outlet 422 are removed to prevent residual fluid from dripping into the vacuum chamber 2. Then, the bellows of the working fluid inlet 421 and the working fluid outlet 422 are connected to the new target body 4, and then the new target body 4 is installed on the mounting table 51 through the hook 52, realizing the disassembly and installation under vacuum conditions, and then repeating the above operations. The operation is very convenient, reducing labor intensity and labor hours.

[0059] The present invention provides a mobile target for neutron generation, which is mainly used for a mobile target for neutron generation in a BNCT device, and has the following beneficial effects:

[0060] 1. By using a mobile device to control the left and right reciprocating motion of the target, the problem of high local heat caused by beam concentration of the existing static target is solved, which effectively reduces the heat deposition per unit volume of the target and also reduces the peak value of target heat concentration, thus reducing the requirements for proton beam current;

[0061] 2. By using a mobile device to control the left and right reciprocating motion of the target, the heat exchange area of ​​the target is increased, the heat dissipation limitation of the target is effectively improved, the heat exchange is enhanced, the risk of target melting is reduced, and the stability of equipment operation is improved;

[0062] 3. Since the target body is directly connected to the mobile device through a hook assembly, it is easy to install and disassemble, thus reducing the cost of replacing the target body;

[0063] 4. It can adapt to different proton beam spots, with less beam loss and low requirements for accelerators;

[0064] 5. By adopting single-phase water-cooled serial flow channels, the flow is uniform, the heat exchange stability is high, and the reliability is strong.

[0065] The rest of this embodiment is the same as the first embodiment. The features not explained in this embodiment are all based on the explanations in the first embodiment and will not be described in detail here.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A mobile target system for neutron generation, characterized in that: The invention comprises a vacuum chamber, a moving device installed in the vacuum chamber, and a target body, wherein the moving device is installed on the top inner wall of the vacuum chamber, and the target body is detachably installed on the moving device through a hook assembly, and the target body comprises a metal substrate and a target body shell, and the target body shell is detachably installed on the mounting table of a linear guide screw device through a hook assembly, and the target body shell is made of 304 stainless steel or nuclear stainless steel, and a rubber gasket is arranged between the metal substrate and the target body shell; a target material filling groove is arranged on the front side of the metal substrate, and the target material is filled in the groove and sealed by hot isostatic pressing through a sealing metal film; a serial water-cooled heat exchange channel is formed in the gap between the back side of the metal substrate and the front side of the target body shell; a back side of the metal substrate is provided with a target material filling groove ... a target material filling groove is filled in the groove and sealed by hot isostatic pressing through a sealing metal film; a back side of the metal substrate is provided with a target material filling groove, and a target material filling groove is filled in the groove and sealed by hot isostatic pressing through a sealing metal film; a back side of the metal substrate is provided with a target material filling groove, and a target material filling groove is filled in the groove and sealed by hot isostatic pressing through a sealing metal film; a back side of the metal substrate is provided with a target material filling groove, and a target material filling groove is filled in the groove, and a target material filling groove is filled in the groove and sealed by hot isostatic pressing through a sealing metal film; a back side of the metal substrate is provided with a target material filling groove, and a target material filling groove is filled in the groove, and a target material filling groove is filled in the groove and sealed by hot isostatic pressing through a sealing metal film; a back side of the metal substrate is provided with A plurality of guide plates are provided on the surface, and the height of the guide plates is 5mm. The front side of the target shell is provided with gap grooves matched with the height of the guide plates, and the guide plates and the gap grooves form the serial water-cooling heat exchange channel; the back side of the target shell is provided with a working fluid inlet and a working fluid outlet for conveying cooling working fluid, and the working fluid inlet and the working fluid outlet are both connected with bellows and are connected with the serial water-cooling heat exchange channel; a first pit with a fluid inlet section is provided at the working fluid inlet, and a second pit with a fluid collection section is provided at the working fluid outlet, and the first pit and the second pit are connected with the serial water-cooling heat exchange channel; the moving device can control the target to reciprocate in the vacuum chamber to disperse the heat deposition inside the target, and the moving device and the target are arranged vertically.

2. A mobile target system for neutron generation according to claim 1, characterized in that: The moving device includes a linear guide screw device and a stepper motor, both of which are arranged above the target body. The linear guide screw device is installed on the top inner wall of the vacuum chamber. One end of the linear guide screw device is connected to the stepper motor. The stepper motor drives the screw to rotate forward and reverse to drive the target body to reciprocate left and right.

3. A mobile target system for neutron generation according to claim 2, characterized in that: The hook assembly includes a mounting platform and a hook, wherein the mounting platform is arranged below the linear guide screw device, and the hook is arranged above the target body, and the target body is detachably mounted on the mounting platform of the linear guide screw device through the hook, the hook is provided with a rectangular protrusion, and the mounting platform is provided with a mounting groove adapted to the rectangular protrusion.

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