High-efficiency heat-removing neutron target device for electron accelerator boron neutron capture therapy
By combining electron beam modulation and a heavy water cooling system, the heat dissipation problem caused by the high-power particle beam in the electron accelerator boron neutron capture therapy system was solved, ensuring the reliability of the BNCT target and the stability of the treatment system.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- INST OF FLUID PHYSICS CHINA ACAD OF ENG PHYSICS
- Filing Date
- 2026-04-30
- Publication Date
- 2026-06-05
AI Technical Summary
In existing electron accelerator boron neutron capture therapy systems, the BNCT target faces heat dissipation problems caused by high-power particle beams, target damage caused by high temperatures, and accelerator vacuum rupture issues that have not been effectively resolved.
An electron beam control system is used to expand or scan the electron beam into a large-area beam spot. Combined with a heavy water chamber, an X-ray conversion target, and a high-efficiency heat exchange substrate, efficient heat dissipation is achieved through a circulating heavy water cooling system to reduce the electron beam power density. The heat is also quickly removed through a dual-circulation cooling system.
This effectively reduces the electron beam power density of the BNCT target, avoiding target damage and accelerator vacuum rupture caused by high temperatures, thus ensuring the reliability and stability of the treatment system.
Smart Images
Figure CN122160987A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of boron neutron capture therapy technology, and more specifically, to a highly efficient heat-dissipating neutron target device for boron neutron capture therapy using an electron accelerator. Background Technology
[0002] Boron neutron capture therapy (BNCT) is a novel cancer treatment method often referred to as the fifth type of cancer therapy. It combines the targeted application of boron drugs with the precise killing of tumor cells by heavy ions, creating a "binary" targeted radiotherapy technique. The basic principle of BNCT is to use boron-rich neutrons to target and kill tumor cells with heavy ions. 10 Drug B is injected into cancer patients, where it is metabolized and accumulated in tumor cells. Then, the tumor area is irradiated using a superthermal neutron beam generated by a BNCT device. 10 B has a high reaction cross-section to ultrathermal neutrons, and the generated Li and α ions can perform targeted elimination of tumor cells with cell-level precision, while substances in normal cells have a very low reaction cross-section to ultrathermal neutrons, thus protecting normal cells.
[0003] Boron neutron capture therapy (BNCT) systems based on electron accelerators have been proposed in the literature. However, because BNCT targets have very high particle beam power (tens to hundreds of kW) and the generated X-rays produce a strong background radiation dose, this leads to additional non-therapeutic radiation exposure, which is detrimental to the patient's health. For example, Chinese patent CN111135477A describes a boron neutron capture therapy system based on an electron accelerator. In this system, the BNCT target adopts a design based on the mainstream proton accelerator BNCT neutron target structure. The therapeutic neutron beam is along the direction of the electron beam's target impact. The X-ray dose rate generated along the electron beam direction (forward) is higher than that in other directions, resulting in a background X-ray fluence in the therapeutic neutron beam direction that is much higher than the neutron beam fluence. Furthermore, the heat dissipation of the high-power electron beam has not been optimized. Additionally, Chinese patent CN114159702A, concerning a boron neutron capture therapy device and method based on a high-energy electron accelerator, utilizes an electron beam to target the object. The electron beam is extracted through an electron transmission window (such as a 50μm titanium window) and then strikes the target, with an energy of 20-140MeV. This leads to significant thermal power deposition on the titanium window, posing a substantial risk of vacuum leakage. To disperse the electron beam power, a rotating or translational target is used to enhance the conversion target's power tolerance. However, rotating or translational targets require complex structures such as motors and may fail under strong radiation.
[0004] Neither of the aforementioned two approaches addresses the heat dissipation issues encountered with high-power electron beam targeting. In particular, BNCT treatments typically last 30 minutes to an hour, or even longer, while the electron beam power reaches tens to hundreds of kW. Without efficient heat dissipation design, the BNCT target faces problems such as target burn-out and long-term operational reliability issues. Therefore, there is an urgent need to develop a highly efficient heat-dissipating neutron target device for electron accelerator boron neutron capture therapy (BNCT), reducing or even eliminating the risks caused by high temperatures, ensuring the reliable and stable operation of the BNCT system, guaranteeing treatment quality, and avoiding the heat dissipation problems caused by high-power particle beams, as well as target damage and accelerator vacuum rupture due to high temperatures. Summary of the Invention
[0005] The technical problems to be solved by this invention are heat dissipation problems caused by high-power particle beams in BNCT targets, as well as target damage and accelerator vacuum breakage caused by high temperatures.
[0006] To address the aforementioned technical problems, this invention provides a highly efficient heat-dissipating neutron target device for boron neutron capture therapy using an electron accelerator. The device includes: an electron beam control system for expanding the beam or enlarging the beam cross-sectional area through electron beam scanning, uniformly dispersing the electron beam into circular, elliptical, or square spots, but not limited to the listed shapes, as long as the beam is enlarged, thereby reducing the electron beam power density on the composite target surface and ensuring the composite target operates within a reliable temperature range; the electron beam generated by the electron accelerator is typically a millimeter-scale beam spot, typically expanded or scanned into a circular beam spot with a diameter of several millimeters to tens of millimeters, such as 10-70 mm; and a beam transmission vacuum pipe with two ends. In the process, the diameter of one end of the beam transmission vacuum pipe is smaller than that of the other end; one section of the electron beam control system is a vacuum flange, which connects to the connecting flange at the electron accelerator beam outlet; the heavy water chamber is used to contain circulating heavy water; the circulating heavy water surrounds one end of the electron beam transmission pipe and the entire X-ray conversion target and high-efficiency heat exchange substrate structure. On the one hand, the circulating heavy water acts as a neutron conversion target to convert high-energy X-rays into photoneutrons; on the other hand, the circulating heavy water serves as the cooling medium for the first cycle. The heavy water chamber has an inlet and an outlet, which are connected to a cooler to form the first cooling cycle; the side wall of the heavy water chamber has an inlet connected to the cooler outlet and an outlet connected to the cooler inlet. The cooler is cooled by air or by the second cycle. Cooling is achieved through a second cooling cycle, consisting of either water cooling, air cooling, or cooling water cooling. This second cycle ultimately removes heat to achieve cooling. The composite target comprises an X-ray conversion target and a high-efficiency heat exchange substrate, sequentially positioned at the other end of the beam transmission vacuum pipe and located within the heavy water chamber. At least one side of the high-efficiency heat exchange substrate contacts the circulating heavy water within the heavy water chamber. A cooling array is positioned on the side of the high-efficiency heat exchange substrate facing the heavy water to increase the contact area with the circulating heavy water and enhance heat dissipation efficiency. The internal flow of heavy water can achieve efficient heat exchange between the substrate and the circulating heavy water through rapid flow, even turbulence or phase change. The electron beam is converted into high-energy X-rays by the X-ray conversion target, forming a bremsstrahlung continuous spectrum. The beam generates photoneutrons through photonuclear reactions of deuterium atoms in heavy water. A neutron beam reflector, used to reflect neutrons emitted from different directions to a predetermined neutron beam outlet, includes a main body covering the outside of the heavy water chamber and a channel leading to the neutron beam outlet. A collimator is located at the outlet end near the neutron beam outlet. A shielding body, covering the outside of the neutron beam reflector and collimator, collimates the neutron beam to the shape and size required for treatment and further absorbs X-rays and non-superheated neutrons. A neutron beam modulator / shaper, located in the channel of the neutron beam reflector, is used to modulate and optimize the neutron beam at the outlet, ensuring that the proportion of neutrons required for 0.5 eV-10 keV treatment meets the requirements recommended by the IAEA.
[0007] According to embodiments of the present invention, the high-efficiency heat-dissipating neutron target device for boron neutron capture therapy in electron accelerators may further include: an X-ray absorber, wherein the direction of the radial neutron beam exit within the collimator gradually narrows, and the X-ray absorber is disposed inside the collimator to further reduce the background radiation dose generated by X-rays, thereby meeting the requirements recommended by the IAEA. Materials such as Bi or Bi alloys, or Bi-containing compounds are used.
[0008] According to embodiments of the present invention, the highly efficient heat-dissipating neutron target device for boron neutron capture therapy in electron accelerators may further include: a thermal neutron absorber, disposed between the neutron beam moderator and the X-ray absorber, for reducing the proportion of thermal neutrons to meet the requirements recommended by the IAEA. Materials with large thermal neutron absorption cross-sections, such as Gd and Ga, are used.
[0009] According to an embodiment of the present invention, the X-ray conversion target may be a refractory material with a high atomic number, and may include one or more metals selected from tungsten, tantalum, and gold, or a composite material containing these metals.
[0010] According to an embodiment of the present invention, the area of the X-ray conversion target may not be less than the size of the electron beam spot of the target, and the thickness of the X-ray conversion target is determined by the energy of the electron beam generated by the electron accelerator, wherein when the electron beam is 10MeV, the thickness is 0.5mm-5mm.
[0011] According to embodiments of the present invention, the high-efficiency heat exchange substrate may be made of a high thermal conductivity material, including copper, aluminum, gold, diamond, or a composite material of diamond and metals. The thickness of the high-efficiency heat exchange substrate is from several millimeters to tens of millimeters, and its cross-sectional size is not smaller than that of an X-ray conversion target.
[0012] According to embodiments of the present invention, the cooling array may employ a cooling microchannel array. The cross-section of the cooling microchannel may be one or more of circular, square, and elliptical shapes, with rounded corners, so that the circulating heavy water flowing inside the microchannel can fully contact the substrate. Its maximum size is sub-mm to several mm. The microchannels may be uniformly or non-uniformly arranged, with spacing and equivalent diameter comparable, typically on the order of mm, and the number of microchannels ≥ 1.
[0013] According to embodiments of the present invention, the cooling array can be a cooling microchannel array, and the cross-section of the cooling microchannel can be semi-circular, square, or other open shapes. Its maximum size is sub-mm to several mm. The microchannels can be uniformly or non-uniformly arranged, with equal spacing and equivalent diameter, typically on the order of mm, and the number of microchannels is ≥1.
[0014] According to an embodiment of the present invention, the X-ray conversion target and the high heat transfer substrate can be integrated by one or more processes including vacuum brazing, diffusion welding, friction welding, and casting to ensure efficient heat conduction.
[0015] According to an embodiment of the present invention, since the X-ray beam generated by the electron beam bombarding the X-ray conversion target is forward-oriented, the neutron beam generated by the composite target is guided out from a direction that forms a certain angle with the direction of the electron beam's impact, thereby reducing the background X-ray radiation in the direction of the neutron beam. Preferably, 90 degrees is used.
[0016] Compared with the prior art, the technical solution provided by the embodiments of the present invention can achieve at least the following beneficial effects:
[0017] This invention proposes a highly efficient heat-dissipating neutron target device for boron neutron capture therapy (BNCT) using an electron beam control system and an integrated neutron conversion and heat dissipation target consisting of an X-ray conversion target, a high-heat-transfer substrate, and circulating heavy water. This distributes the electron beam power over a large area, reducing the electron beam power density on the target. Simultaneously, it efficiently and rapidly removes the power deposited on the target, thereby maintaining the high-temperature regions, such as the X-ray conversion target directly irradiated by the electron beam, within the temperature range for long-term reliable material operation. This reduces or even eliminates the risks associated with high temperatures, ensuring the reliable and stable operation of the BNCT system and guaranteeing treatment quality. This invention solves the current problems faced by BNCT targets, such as heat dissipation issues caused by high-power particle beams, target damage due to high temperatures, and accelerator vacuum rupture.
[0018] The present invention proposes a high-efficiency heat dissipation neutron target device for boron neutron capture therapy in electron accelerators. By combining an electron beam control system and a composite target of "X-ray conversion target-high-efficiency heat exchange substrate-circulating heavy water", the high-power electron beam can be dispersed over a large target area, reducing the power density of the electron beam. Combined with the high-efficiency heat exchange substrate and circulating heavy water, the power deposited by the electron beam can be quickly and efficiently carried away and dissipated.
[0019] The present invention provides a highly efficient heat-dissipating neutron target device for boron neutron capture therapy using an electron accelerator. The electron beam control system expands the electron beam generated by the electron accelerator by tens to hundreds of times through direct beam expansion or electron beam scanning. Compared with the rotating or translational targets in the prior art, the target device is more reliable and has a simpler structure.
[0020] According to the present invention, a high-efficiency heat dissipation neutron target device for boron neutron capture therapy in an electron accelerator is proposed, wherein the circulating heavy water is not only a photoneutron conversion target, but also connected to a cooler to cool the heat deposited by the electron beam flowing into the heavy water. The cooler is then cooled by an external cooling circulation system (such as water cooling or air cooling), that is, a dual-circulation cooling system is adopted, with the circulating heavy water being the medium of the first cooling circulation system. Attached Figure Description
[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention.
[0022] Figure 1 This shows the layout diagram of BNCT based on the petal accelerator;
[0023] Figure 2 This is a schematic cross-sectional view of a highly efficient heat-dissipating neutron target device for boron neutron capture therapy in an electron accelerator according to an embodiment of the present invention.
[0024] Figure 3 yes Figure 2 A cross-sectional schematic diagram;
[0025] Figure 4a This is a schematic cross-sectional view of a cooling microchannel array according to an embodiment of the present invention;
[0026] Figure 4b yes Figure 4a A cross-sectional schematic diagram;
[0027] Figure 4c This is a schematic cross-sectional view of a cooling microchannel array according to an embodiment of the present invention;
[0028] Figure 4d yes Figure 4c A cross-sectional schematic diagram;
[0029] Figure 5 This is a schematic diagram illustrating the energy flow of a highly efficient heat-dissipating neutron target device for boron neutron capture therapy in an electron accelerator according to an embodiment of the present invention;
[0030] Figure 6 This is a schematic diagram illustrating the connection of a cooling cycle for a highly efficient heat-dissipating neutron target device for boron neutron capture therapy in an electron accelerator according to an embodiment of the present invention. Detailed Implementation
[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0032] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains. The terms “first,” “second,” and similar terms used in the specification and claims of this patent application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an” or “a” and similar terms do not indicate a limitation of quantity, but rather indicate the presence of at least one.
[0033] Figure 1 This shows the layout diagram of BNCT based on the petal accelerator; Figure 2 This is a schematic cross-sectional view of a highly efficient heat-dissipating neutron target device for boron neutron capture therapy in an electron accelerator according to an embodiment of the present invention. Figure 3 yes Figure 2 A cross-sectional schematic diagram.
[0034] like Figures 1 to 3 As shown, the high-efficiency heat dissipation neutron target device for boron neutron capture therapy using an electron accelerator includes: an electron beam control system 11, a beam transmission vacuum pipe 1, a heavy water chamber 2, a composite target, a neutron beam reflector 5, a shield 9, and a neutron beam slowing and shaping body 6.
[0035] The electron beam control system 11 is used to expand the beam or enlarge the beam cross-sectional area by scanning the electron beam, and to uniformly disperse the electron beam into circular spots, elliptical spots, square spots, etc., but not limited to the listed shapes of the beam spots. As long as the beam spot is enlarged, the power density of the electron beam on the composite target surface is reduced, ensuring that the composite target operates within a reliable temperature range. The electron beam generated by the electron accelerator is typically a millimeter-level beam spot. It is typically expanded or scanned into a circular beam spot with a beam spot diameter of several millimeters to tens of millimeters, such as 10-70 mm.
[0036] The present invention provides a highly efficient heat-dissipating neutron target device for boron neutron capture therapy using an electron accelerator. The electron beam control system expands the electron beam generated by the electron accelerator by tens to hundreds of times through direct beam expansion or electron beam scanning. Compared with the rotating or translational targets in the prior art, the target device is more reliable and has a simpler structure.
[0037] The beam transmission vacuum pipe 1 has two ends, wherein the diameter of one end of the beam transmission vacuum pipe 1 is smaller than that of the other end; one section of the electron beam control system 11 is a vacuum flange, which is connected to the connecting flange at the exit port of the electron accelerator.
[0038] The heavy water chamber 2 is used to contain circulating heavy water. The circulating heavy water is not only used for the photoneutron conversion target, but is also connected to a cooler to cool the heat deposited by the electron beam flowing into the heavy water. The cooler is then cooled by an external cooling circulation system (such as water cooling or air cooling), which means that a dual-circulation cooling system is adopted, with the circulating heavy water serving as the medium for the first cooling circulation system.
[0039] The composite target includes an X-ray conversion target 3 and a high-efficiency heat exchange substrate 4, which are sequentially disposed at the other end of the beam transmission vacuum pipe 1 and located in the heavy water chamber 2. At least one side of the high-efficiency heat exchange substrate 4 contacts the circulating heavy water in the heavy water chamber 2. A cooling array is provided on the side of the high-efficiency heat exchange substrate 4 facing the heavy water to increase the contact area with the circulating heavy water and increase the heat dissipation efficiency. The heavy water flowing inside can achieve high-efficiency heat exchange between the substrate and the circulating heavy water through rapid flow, or even the formation of turbulence or the generation of a phase change. The electron beam is converted into high-energy X-rays through the X-ray conversion target 3 to form a bremsstrahlung continuous spectrum. The high-energy X-rays generate photoneutrons in the heavy water through the photonuclear reaction of deuterium atoms.
[0040] The neutron beam reflector 5 is used to reflect neutrons emitted from different directions to a predetermined neutron beam outlet. It includes a main body covering the outside of the heavy water chamber 2 and a channel to the neutron beam outlet. A collimator 10 is provided at the outlet end near the neutron beam outlet.
[0041] The shield 9 covers the outside of the neutron beam reflector 5 and the collimator 10. The collimator 10 and the shield 9 collimate the neutron beam to the shape and size required for treatment and further absorb X-rays and non-superheated neutrons.
[0042] A neutron beam moderator and shaper 6 is disposed in the channel portion of the neutron beam reflector 5 to optimize the slowing and spectral shape of the neutron beam at the outlet. This ensures that the proportion of neutron beams required for 0.5 eV-10 keV therapy meets the requirements recommended by the IAEA.
[0043] The present invention proposes a high-efficiency heat dissipation neutron target device for boron neutron capture therapy in electron accelerators. By combining an electron beam control system and a composite target of "X-ray conversion target-high-efficiency heat exchange substrate-circulating heavy water", the high-power electron beam can be dispersed over a large target area, reducing the power density of the electron beam target. Combined with the high-efficiency heat exchange substrate and circulating heavy water, the power deposited by the electron beam can be quickly and efficiently carried away and dissipated.
[0044] According to one or more embodiments of the present invention, the high-efficiency heat-dissipating neutron target device for boron neutron capture therapy in electron accelerators further includes: an X-ray absorber 7, wherein the direction of the radial neutron beam exit point inside the collimator 10 gradually narrows, and the X-ray absorber 7 is disposed inside the collimator 10 to further reduce the background radiation dose generated by X-rays, thereby meeting the requirements recommended by the IAEA. Materials such as Bi or Bi alloys, or Bi-containing compounds are used.
[0045] According to one or more embodiments of the present invention, the highly efficient heat-dissipating neutron target device for boron neutron capture therapy in electron accelerators further includes: a thermal neutron absorber 8, disposed between the neutron beam moderator and shaper 6 and the X-ray absorber 7, for reducing the proportion of thermal neutrons to meet the requirements recommended by the IAEA. Materials with large thermal neutron absorption cross-sections, such as Gd and Ga, are used.
[0046] According to one or more embodiments of the present invention, the X-ray conversion target 3 is a refractory material with a high atomic number, including one or more metals selected from tungsten, tantalum, and gold, or a composite material containing these metals.
[0047] According to one or more embodiments of the present invention, the area of the X-ray conversion target 3 is not less than the size of the electron beam spot of the target, and the thickness of the X-ray conversion target 3 is determined by the energy of the electron beam generated by the electron accelerator, wherein when the electron beam is 10MeV, the thickness is 0.5mm-5mm.
[0048] According to one or more embodiments of the present invention, the high-efficiency heat exchange substrate 4 is made of a high thermal conductivity material, including one or more composite materials of copper, aluminum, gold, diamond, and diamond and metal. The thickness of the high-efficiency heat exchange substrate 4 is from several millimeters to tens of millimeters, and its cross-sectional size is not smaller than that of the X-ray conversion target 3.
[0049] Figure 4a This is a schematic cross-sectional view of a cooling microchannel array according to an embodiment of the present invention; Figure 4b yes Figure 4a A cross-sectional schematic diagram.
[0050] like Figure 4a and 4b As shown, the cooling array employs a cooling microchannel array 41. The cross-section of the cooling microchannels is one or more of the following: circular, square, or elliptical, with rounded corners, allowing the circulating heavy water flowing inside the microchannels to fully contact the substrate. Its maximum size is sub-mm to several mm. The microchannels can be arranged uniformly or non-uniformly, with spacing comparable to the equivalent diameter, typically on the order of mm. The number of microchannels is ≥1.
[0051] Figure 4c This is a schematic cross-sectional view of a cooling microchannel array according to an embodiment of the present invention; Figure 4d yes Figure 4c A cross-sectional schematic diagram;
[0052] like Figure 4c and 4d As shown, the cooling array employs a cooling micro-groove array 42. The cross-section of the cooling micro-grooves is semi-circular, square, or other open shapes. Their maximum size is sub-mm to several mm. The micro-grooves can be uniformly or non-uniformly arranged, with equal spacing and equivalent diameter, typically on the order of mm. The number of micro-grooves is ≥1.
[0053] According to one or more embodiments of the present invention, the X-ray conversion target 3 and the high heat transfer substrate are integrated by one or more processes including vacuum brazing, diffusion welding, friction welding, and casting to ensure efficient heat conduction.
[0054] According to one or more embodiments of the present invention, since the X-ray beam generated by the electron beam bombarding the X-ray conversion target 3 is forward-oriented, the neutron beam generated by the composite target is guided out from a direction forming a certain angle with the direction of the electron beam, thereby reducing the X-ray background radiation in the direction of the neutron beam. Typically, 90 degrees is used.
[0055] Figure 5 This is a schematic diagram illustrating the energy flow of a highly efficient heat-dissipating neutron target device for boron neutron capture therapy in an electron accelerator according to an embodiment of the present invention; Figure 6 This is a schematic diagram illustrating the connection of a cooling cycle for a highly efficient heat-dissipating neutron target device for boron neutron capture therapy in an electron accelerator according to an embodiment of the present invention.
[0056] like Figure 5 and Figure 6 As shown, circulating heavy water encloses one end of the electron beam transmission pipe and the entire X-ray conversion target 3 and high-efficiency heat exchange substrate 4 structure. On the one hand, the circulating heavy water acts as a neutron conversion target to convert high-energy X-rays into photoneutrons; on the other hand, the circulating heavy water serves as the cooling medium for the first cycle. The heavy water chamber 2 is equipped with an inlet and an outlet, which are respectively connected to the cooler to form the first cooling cycle. The side wall of the heavy water chamber is equipped with an inlet connected to the cooler outlet and an outlet connected to the cooler inlet. The cooler is cooled by air cooling or by cooling water in the second cycle. Both air cooling and cooling water constitute the second cooling cycle. The second cycle ultimately removes heat to achieve the purpose of cooling.
[0057] This invention proposes a highly efficient heat-dissipating neutron target device for boron neutron capture therapy (BNCT) using an electron beam control system and an integrated neutron conversion and heat dissipation target consisting of an X-ray conversion target, a high-heat-transfer substrate, and circulating heavy water. This distributes the electron beam power over a large area, reducing the electron beam power density on the target. Simultaneously, it efficiently and rapidly removes the power deposited on the target, thereby maintaining the high-temperature regions, such as the X-ray conversion target directly irradiated by the electron beam, within the temperature range for long-term reliable material operation. This reduces or even eliminates the risks associated with high temperatures, ensuring the reliable and stable operation of the BNCT system and guaranteeing treatment quality. This invention solves the current problems faced by BNCT targets, such as heat dissipation issues caused by high-power particle beams, target damage due to high temperatures, and accelerator vacuum rupture.
[0058] The above description is merely an exemplary embodiment of the present invention and is not intended to limit the scope of protection of the present invention, which is determined by the appended claims.
Claims
1. A highly efficient heat-dissipating neutron target device for boron neutron capture therapy in electron accelerators, wherein, include: The electron beam control system is used to expand the beam or increase the cross-sectional area of the beam by scanning the electron beam, thereby reducing the electron beam power density on the composite target surface and ensuring that the composite target operates within a reliable temperature range. The beam transmission vacuum pipe has two ends, wherein the diameter of one end of the beam transmission vacuum pipe is smaller than that of the other end; one section of the electron beam control system is a vacuum flange, which is connected to the connecting flange at the exit port of the electron accelerator. Heavy water chamber, used to contain circulating heavy water; The composite target includes an X-ray conversion target and a high-efficiency heat exchange substrate, which are sequentially disposed at the other end of the beam transmission vacuum pipe and located within the heavy water chamber. At least one side of the high-efficiency heat exchange substrate contacts the circulating heavy water within the heavy water chamber. A cooling array is disposed on the side of the high-efficiency heat exchange substrate facing the heavy water to increase the contact area with the circulating heavy water and enhance heat dissipation efficiency. The circulating heavy water can achieve efficient heat exchange between the substrate and the circulating heavy water through rapid flow, even turbulence or phase change. The electron beam is converted into high-energy X-rays by the X-ray conversion target, forming a bremsstrahlung continuous spectrum. The high-energy X-rays generate photoneutrons in the heavy water through photonuclear reactions of deuterium atoms. A neutron beam reflector is used to reflect neutrons emitted from different directions to a predetermined neutron beam outlet. It includes a main body covering the outside of the heavy water chamber and a channel to the neutron beam outlet, wherein a collimator is provided at the outlet end near the neutron beam outlet. A shielding body covers the outside of the neutron beam reflector and collimator, which, together with the shielding body, collimates the neutron beam to the shape and size required for treatment and further absorbs X-rays and other non-superthermal neutrons; A neutron beam moderator and shaper is installed in the channel section of the neutron beam reflector to optimize the spectral shape of the neutron beam at the outlet.
2. The high-efficiency heat-dissipating neutron target device for boron neutron capture therapy in electron accelerators as described in claim 1, wherein, Also includes: The X-ray absorber has a gradually narrowing radial neutron beam outlet inside the collimator. An X-ray absorber is provided inside the collimator to further reduce the background radiation dose generated by X-rays.
3. The high-efficiency heat-dissipating neutron target device for boron neutron capture therapy in electron accelerators as described in claim 2, wherein, Also includes: A thermal neutron absorber is disposed between the neutron beam moderator and the X-ray absorber to reduce the proportion of thermal neutrons.
4. The high-efficiency heat-dissipating neutron target device for boron neutron capture therapy in electron accelerators as described in claim 1, wherein, The X-ray conversion target is a refractory material with a high atomic number, including one or more metals selected from tungsten, tantalum, and gold, or a composite material containing these metals.
5. The high-efficiency heat-dissipating neutron target device for boron neutron capture therapy in electron accelerators as described in claim 1, wherein, The area of the X-ray conversion target is not less than the size of the electron beam spot used for target firing. The thickness of the X-ray conversion target is determined by the energy of the electron beam generated by the electron accelerator. When the electron beam is 10 MeV, the thickness is 0.5 mm to 5 mm.
6. The high-efficiency heat-dissipating neutron target device for boron neutron capture therapy in electron accelerators as described in claim 1, wherein, The high-efficiency heat exchange substrate uses a high thermal conductivity material, including one or more composite materials of copper, aluminum, gold, diamond, and diamond and metal.
7. The high-efficiency heat-dissipating neutron target device for boron neutron capture therapy in electron accelerators as described in claim 1, wherein, The cooling array is a cooling microchannel array. The cross-section of the cooling microchannel is one or more of the following: circular, square, and elliptical, with rounded corners, so that the circulating heavy water flowing inside the microchannel can fully contact the substrate.
8. The high-efficiency heat-dissipating neutron target device for boron neutron capture therapy in electron accelerators as described in claim 1, wherein, The cooling array is a cooling micro-groove array, and the cross-section of the cooling micro-groove is semi-circular, square, or other open shape.
9. The high-efficiency heat-dissipating neutron target device for boron neutron capture therapy in electron accelerators as described in claim 1, wherein, The X-ray conversion target and the high heat transfer substrate are integrated using one or more processes, including vacuum brazing, diffusion welding, friction welding, and casting, to ensure efficient heat transfer.
10. The high-efficiency heat-dissipating neutron target device for boron neutron capture therapy in electron accelerators as described in claim 1, wherein, Since the X-ray beam generated by the electron beam bombarding the X-ray conversion target is forward-oriented, the neutron beam generated by the composite target is drawn out from a direction that forms a certain angle with the direction of the electron beam hitting the target, thereby reducing the background radiation of X-rays in the direction of the neutron beam.