CN115151013A - Neutron capture irradiation system - Google Patents
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- CN115151013A CN115151013A CN202211056661.7A CN202211056661A CN115151013A CN 115151013 A CN115151013 A CN 115151013A CN 202211056661 A CN202211056661 A CN 202211056661A CN 115151013 A CN115151013 A CN 115151013A
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- A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
- A61N2005/1085—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy characterised by the type of particles applied to the patient
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Abstract
The application discloses neutron capture irradiation system utilizes linear accelerator to produce the high current charged particle beam, and rotary-type distributed target converts the high current particle beam stream into high-energy neutron beam, utilizes the body of slowing down and high-energy neutron beam to take place interact, thereby makes high-energy neutron beam loss part energy slows down to epithermal neutron energy scope, obtains epithermal neutron, forms epithermal neutron beam, and epithermal neutron beam that will pass through the multislit part converts into the neutron beam that intensity is grid distribution. Therefore, the duty ratio of the particle beam generated by the linear accelerator is consistent with the rotation frequency of the rotary distributed target, the action probability of the high-current charged particle beam and the non-target is reduced, the proton beam is ensured to continuously and stably react with the target, the utilization rate of the beam is improved, the neutron beam with higher purity can be obtained, the tumor target area can reach high-dose distribution, the normal tissue does not reach the tolerance threshold dose, and the treatment gain is improved.
Description
Technical Field
The present application relates to the field of medical treatment, and more particularly to a neutron capture irradiation system.
Background
In recent years, malignant tumors become the leading cause of death of residents in China, and for example, 2015 is taken as an example, 392.9 thousands of new malignant tumors are estimated to be generated in the whole country, wherein 233.8 thousands of death cases are estimated. Surgery, radiation therapy and chemotherapy are one of the three major approaches to cancer treatment. Radiotherapy is one of the most widely used treatment methods because of its advantages of less damage, less pain in treatment, easy acceptance by patients, etc., and the radiotherapy mode of Boron Neutron Capture Therapy (BNCT) has the most ideal effect.
In a boron neutron capture treatment system driven by a linear accelerator, a neutron irradiation method is to accelerate a charged particle beam by a common electrostatic proton linear accelerator, the charged particle beam is accelerated to energy enough to overcome the coulomb repulsion of target material atomic nuclei, the target material is bombarded to generate a neutron beam, the neutron beam passes through a specific beam shaping device to obtain certain neutron intensity, and finally the neutron beam is converged in a concentrated manner by a collimator and irradiates a target area of a human body.
Therefore, how to increase the neutron yield and simultaneously increase the skin tolerance dose and the tumor irradiation dose is a technical problem to be solved urgently by those skilled in the art.
Disclosure of Invention
Based on the above problems, the present application provides a neutron capture irradiation system, which can greatly improve the neutron yield and improve the wide field collimation mode skin tolerance dose and the irradiation dose of tumors.
In order to solve the above problem, the technical solution provided by the embodiment of the present application is as follows:
a neutron capture irradiation system, the system comprising: the device comprises a linear accelerator, a target, a supporting body, a bearing, a driving component, a slowing body and a space division modulation collimation component multi-slit collimator;
the carrier carries at least three targets, each target is uniformly distributed on the carrier by taking the geometric center of the carrier as a circle center, the distances from each target to the geometric center of the carrier are the same, and gaps exist among the targets;
the driving part drives the bearing body to rotate by taking the bearing as an axis according to a preset rotation frequency through the bearing, so that the targets are aligned with the outlet of the accelerator in sequence; the geometric center of the bearing body and the geometric center of the bearing are on the same straight line;
the outlet of the target is aligned with the slowing-down body; the outlet of the slowing-down body is aligned with the multi-slit collimator of the space division modulation collimation component;
the linear accelerator is used for generating a high-current particle beam according to a preset duty ratio;
the target is used for converting the high-current particle beam into a high-energy neutron beam;
the moderating body is used for interacting with the high-energy neutron beam, so that the high-energy neutron beam loses partial energy and is moderated to the energy range of epithermal neutrons to obtain epithermal neutrons and form the epithermal neutron beam; wherein the epithermal neutron energy range is greater than a first threshold and less than a second threshold;
the space division modulation collimation component multi-slit collimator is used for converting the passing epithermal neutron beam flow into a grid-type neutron beam flow and absorbing the non-passing epithermal neutron beam flow.
Optionally, the preset rotation frequency is consistent with the preset duty cycle; the preset duty cycle is adjusted according to the preset rotation frequency.
Optionally, the method further comprises:
the base is connected with the driving part;
the base is used for keeping the driving component, the bearing body and the target stably placed on a plane.
Optionally, the moderator material is one or more of fluoride, heavy water, polyethylene, and graphite.
Optionally, the method further comprises:
the shielding reflector is wrapped outside the slowing-down body and the target material;
the shielding reflector is used for preventing neutrons scattered by the moderator from radiating out when the moderator interacts with the high-energy neutron beam and reflecting neutrons scattered by the moderator when the moderator interacts with the high-energy neutron beam.
Optionally, the shielding reflector comprises a shield and a reflector;
the shielding body is used for preventing neutrons and photons scattered by the moderating body from radiating out when the moderating body interacts with the high-energy neutron beam;
the reflector is used for reflecting neutrons scattered by the moderator when the moderator interacts with the high-energy neutron beam to the moderator, so that the epithermal neutron flux is improved.
Optionally, the shield comprises a neutron shield and a photon shield;
the neutron shielding body is used for shielding the neutrons to prevent the neutrons from causing additional irradiation;
the photon shielding body is used for shielding the photons and preventing the photons from causing additional irradiation.
Optionally, the shield is a boron-containing polyethylene.
Optionally, the reflector material is one or more of polytetrafluoroethylene, beryllium oxide, aluminum oxide, and lead.
Optionally, the method further comprises:
a filter body, an outlet of the moderator body being aligned with the filter body;
the filter is used for filtering thermal neutrons, fast neutrons and gamma rays scattered by the moderator when the moderator forms the epithermal neutron beam to obtain uniform epithermal neutron beam.
Optionally, the filter comprises a thermal neutron filter, a fast neutron filter, and a gamma ray filter;
the thermal neutron filtering body is used for filtering the thermal neutrons;
the fast neutron filtering body is used for filtering the fast neutrons;
the gamma ray filter is used for filtering the gamma ray.
Optionally, the material of the thermal neutron filter is one or more of lithium, boron and cadmium;
the fast neutron filter body is made of nickel;
the gamma ray filter body is made of one or more of lead and bismuth.
Optionally, comprising: the space division modulation collimation component multi-slit collimator is specifically used for forming the passed uniform super-thermal neutron beam into a grid-type particle beam and absorbing the non-passed super-thermal neutron beam.
Optionally, the material of the multi-slit collimator of the spatially-divided modulating collimating component is a lithium-containing polyethylene polymer or a boron-containing polyethylene polymer.
Compared with the prior art, the method has the following beneficial effects:
the application provides a neutron capture irradiation system, utilize linear accelerator to produce particle beam, rotary-type distributed target high current particle beam converts high energy neutron beam into, it takes place inelastic collision with high energy neutron beam to reuse moderator to make high energy neutron beam lose partial energy, with its moderation to epithermal neutron energy scope, in order to obtain epithermal neutron, form epithermal neutron beam, the epithermal neutron beam who will pass through multislit part at last changes and forms grid type particle beam. Therefore, the extraction period of the pulse charged particle beam can be adjusted according to the preset rotating frequency of the driving part, the linear accelerator and the target which drives the bearing body to rotate according to the preset rotating frequency through the bearing by means of the driving part are matched with each other to generate a purer neutron beam, meanwhile, the irradiation volume of normal tissues can be greatly reduced, the tolerance dose threshold of the normal tissues such as skin is obviously improved, the tumor target area reaches high dose distribution, the normal tissues far do not reach the tolerance threshold dose, the normal tissues such as skin are better protected, and the treatment gain is improved.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive exercise.
FIG. 1 is a block diagram of a neutron capture irradiation system according to an embodiment of the present disclosure;
FIG. 2 is a block diagram of another neutron capture irradiation system provided by an embodiment of the present application;
FIG. 3 is a block diagram of yet another neutron capture irradiation system provided by an embodiment of the present application;
FIG. 4 is a block diagram of another neutron capture irradiation system provided by an embodiment of the present application;
FIG. 5 is a conversion diagram of a multi-slit collimator of a spatially-divided modulating collimating component according to an embodiment of the present application;
FIG. 6 is a front view of a beam outlet of a multi-slit collimator of a spatially-divided modulation collimating component according to an embodiment of the present disclosure;
fig. 7 is a front view of a target according to an embodiment of the present application.
Detailed Description
In order to make the technical solutions of the present application better understood, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
In a boron neutron capture treatment system driven by a linear accelerator, a neutron irradiation method is to accelerate a charged particle beam by the linear accelerator, the charged particle beam is accelerated to energy enough to overcome the nuclear coulomb repulsion of target materials, bombards the target materials, generates a neutron beam by nuclear reaction, reshapes and slows down the neutron beam to the energy range of thermal neutrons (E <0.5 eV) and super thermal neutrons (0.5 eV or less E <10 keV) through a specific beam reshaping device, obtains certain neutron intensity, and finally concentrates and converges the neutron beam through a collimator to irradiate a human target area. The charged particle beam generated by the linear accelerator has low intensity in the process of bombarding the neutron beam generated by the target material and has high probability of acting on the non-target material, so that the yield of the generated neutron beam is low, the neutron beam processed by the moderator and the filter is an isotropic divergent beam, and in order to control the shape, the direction and the size of the beam current, the unnecessary neutrons and the unmasked gamma rays outside the beam outlet are reduced, and a collimator is also required to be arranged. The collimating body is usually designed in a large-area hollow forward cone opening mode, and the beam outlet is free of other fine modulation parts. The neutron beam irradiation mode enables neutron beams to be uniformly distributed, all visible skins in a beam irradiation field are exposed in the irradiation field, and due to the fact that the tolerance dose threshold of the skins is low (generally 12.5 Gy) when large-area uniform irradiation is conducted, the skin dose can quickly reach the tolerance dose threshold when neutron irradiation is conducted in a wide-field collimation mode, irradiation time is short, and the dose borne by tumors cannot be higher.
In order to solve the problem, an embodiment of the present application provides a neutron capture irradiation system, a linear accelerator is used to generate a high-current particle beam according to a preset duty ratio, at least three targets on a supporting body drive the supporting body to rotate according to a preset rotation frequency through a bearing by means of a driving component, so that the high-current particle beam is converted into a high-energy neutron beam, a moderator is used to perform inelastic collision with the high-energy neutron beam, so that the high-energy neutron beam loses part of energy, the high-energy neutron beam is slowed to an epithermal neutron energy range to obtain epithermal neutrons, the epithermal neutron beam is formed, and finally, the epithermal neutron beam passing through a multi-slit collimator of a space division modulation collimation component is converted into a grid-type particle beam. The multi-slit collimator of the space division modulation collimation component only allows a preset part of normal tissues such as visible skin and the like to be exposed in an irradiation field, and the irradiated volume of the normal tissues is reduced, so that the more the normal tissues survive, the less the radiation damage reaction of the whole normal tissues is. Therefore, the extraction period of the pulse charged particle beam can be adjusted according to the preset rotating frequency of the driving part, the linear accelerator and the target which drives the bearing body to rotate according to the preset rotating frequency through the bearing by means of the driving part are matched with each other to generate a purer neutron beam, meanwhile, the irradiation volume of the normal tissue can be greatly reduced, the tolerance dose threshold of the normal tissue such as skin is obviously improved, the tumor target area reaches high dose distribution, the normal tissue far does not reach the tolerance threshold dose, the normal tissue such as skin is better protected, and the treatment gain is improved.
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present application, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Referring to fig. 1, fig. 1 is a structural diagram of a neutron beam grid irradiation system according to an embodiment of the present application. As shown in fig. 1, the irradiation system includes a linear accelerator 100, a target 110, a carrier 120, a bearing 130, a driving unit 140, a moderator 150, and a spatial division modulation collimating unit, a multi-slit collimator 160. The carrier 120 carries at least three targets, each target 110 is uniformly distributed on the carrier 120 with the geometric center of the carrier 120 as a circle center, distances from each target 110 to the geometric center of the carrier 120 are the same, and a gap exists between the targets 120, as shown in fig. 7; the driving part 140 drives the carrier 120 to rotate around the bearing 130 as an axis according to a preset rotation frequency by the bearing 130, so that each target 110 is aligned with the outlet of the linear accelerator 100 in sequence; the geometric center of the carrier 120 and the geometric center of the bearing 130 are on the same straight line; the outlet of target 110 is aligned with moderator 150; the exit of the moderator 150 is aligned with the spatially-divided modulating collimating component multi-slit collimator 160.
The driving member 140 may be a device having a driving function, such as a motor.
The linear accelerator 100 is configured to generate a high-current particle beam according to a preset duty cycle. The linac 100 is a charged particle linac, and the charged particle linac 100 generates a charged particle beam having appropriate energy and fluence rate and flux rate (flow intensity) using a magnetic field and an electric field. The charged particle linac 100 includes, but is not limited to, an electrostatic linac, a cyclotron, a synchrotron, a cyclotron + synchrotron, a linac, a laser-driven linac, and the like.
The duty ratio of the particle beam generated by the linear accelerator 100 with the preset rotation frequency is consistent with the preset rotation frequency of the rotating target; the preset duty cycle is adjusted according to the preset rotation frequency.
The duty ratio is the proportion of the time of the beam with respect to the total time in one pulse period, for example, the time of irradiating a certain target in one period is 3uS, and a space of 1uS is left between the target and the next target (the beam does not need to come at this time), so that the duty ratio is 3/(3 + 1) =0.75.
The target 110 is used for converting the high-current particle beam into a high-energy neutron beam. The high current charged particle beam generated by the linear accelerator 100 is consumed to be a high energy neutron beam by bombarding the target 110, and the target 110 is a reaction target which interacts with the charged particles to generate neutrons. When a linear accelerator is used for targeting to generate neutrons, the material of the target needs to be considered, and a high-energy neutron beam is generated by bombarding a lithium target or a beryllium target with a high-current particle beam.
Wherein, the strong flow means that the number of particles coming out in unit time is much larger than the general number.
The moderator 150 is configured to interact with the high-energy neutron beam, so that the high-energy neutron beam loses part of energy and is moderated to the epithermal neutron energy range to obtain epithermal neutrons. The moderating member 150 may interact with the high-energy neutron beam by a nuclear reaction or the like, so that the high-energy neutrons lose part of energy and are moderated to a thermal neutron energy range or an epithermal neutron energy range, and excessive thermal neutrons, fast neutrons and gamma rays are not generated. Wherein, the thermal neutron energy range is less than 0.5 electron volt, and the epithermal neutron energy range is more than 0.5 electron volt and less than 10K electron volt.
The multi-slit collimator 160 of the spatial division modulation collimating component converts the passed epithermal neutron beam to form a beam meeting the spatial division distribution requirement, such as a grid-type neutron beam. The spatial division modulation collimating component 160 converts the passing epithermal neutron beam into a beam meeting the spatial division distribution requirement, such as a grid-type neutron beam, by a shape with a certain block division ratio, such as a grid-type structure. As shown in fig. 5, the spatially-segmented modulating collimator element multi-slit collimator 160 allows only the epithermal neutron beam 161 that does not hit the spatially-segmented modulating collimator absorber 164 to pass through the spatially-segmented modulating collimator element multi-slit collimator exit slit 165 to form a specially-distributed grid-type neutron beam 163, while the epithermal neutron beam that hits the absorbing material in the spatially-segmented modulating collimator element multi-slit collimator is reduced in flux and fluence. The spatially-segmented modulating collimating component multi-slit collimator 160 can expose a predetermined portion (typically 50%) of normal tissue, such as visible skin, to the field of illumination, and the irradiated volume of the normal tissue becomes smaller. The multi-slit collimator 160 is generally made of a polyethylene polymer containing lithium or boron. One side of the multi-slit collimator 160 of the spatial division modulation collimation component, which emits the epithermal neutron beam 161, is a beam outlet. The unshaded parts of the multi-slit collimator 160 of the spatial division modulation collimating component are all multi-slit collimator absorbers 164 of the spatial division modulation collimating component, and the shaded parts of the multi-slit collimator 160 of the spatial division modulation collimating component are all beam outlet slits 165 of the multi-slit collimator of the spatial division modulation collimating component.
The intensity distribution 166 of the epithermal neutron flux 161 along the transverse main axis is approximately gaussian (higher in the middle and gradually lower on both sides).
The intensity distribution 167 on the transverse main axis of the grid-type neutron beam 163 has a continuous peak-valley-shaped intensity distribution.
The absorber can be arranged in a long-strip-shaped fence, a triangular interval distribution, a black-white checkerboard distribution, a honeycomb-shaped sewing and the like, and in principle, the absorber only needs to be arranged to form a shape with a certain splitting ratio, and meets the requirement of space division distribution.
The beam outlet of the multi-slit collimator of the spatial division modulation collimation component can be circular or regular polygon. In this embodiment, a front view of the beam outlet of the multi-slit collimator of the space division modulation collimating component shown in fig. 6 shows a specific configuration of the beam outlet of the multi-slit collimator of the space division modulation collimating component, and the absorbing material of the multi-slit collimator is fixed on the beam outlet and the collimator support 601, and forms an absorber 602 of the multi-slit collimator according to a certain arrangement, which only allows the super-thermal neutron beam to irradiate from the beam outlet slit 603 of the multi-slit collimator.
The application provides a pair of neutron capture irradiation system, utilize linear accelerator to produce the high current particle beam according to predetermineeing the duty cycle, at least three target on the supporting body relies on driver part to pass through the bearing and drives the supporting body and rotate according to predetermineeing the rotational frequency, thereby convert the high current particle beam stream into high-energy neutron beam, reuse moderator and high-energy neutron beam take place inelastic collision, thereby make high-energy neutron beam lose partial energy, slow down it to epithermal neutron energy scope, in order to obtain epithermal neutron, form epithermal neutron beam, at last convert the epithermal neutron beam stream that will pass through the multislot part into grid type particle beam. Therefore, the extraction period of the pulse charged particle beam can be adjusted according to the preset rotating frequency of the driving part, the linear accelerator and the target which is driven by the driving part through the bearing to drive the supporting body to rotate according to the preset rotating frequency are matched with each other to generate a purer neutron beam, meanwhile, the irradiated volume of normal tissues can be greatly reduced, the tolerance dose threshold of the normal tissues such as skin is remarkably improved, the tumor target area reaches high dose distribution, the dose of the normal tissues does not reach the tolerance threshold far, the normal tissues such as skin are better protected, and the treatment gain is improved.
Referring to fig. 2, the neutron beam grid irradiation system provided by the embodiment of the present application may further include a shielding reflector 280 and a base 270, based on the embodiment corresponding to fig. 1. Neutrons generated by the target 210 are distributed anisotropically in direction and energy, and are diffused in all directions when passing through the moderator 250, and if the neutrons are not utilized, energy waste and the problem of small flux of thermal neutrons or epithermal neutrons at the beam outlet of the multi-slit collimator 260 of the spatial division modulation collimation component are caused, so that the shielding reflector 280 can be wrapped outside the moderator 250 and the target 210. In addition, when the driving member 240 rotates, the driving member 240, the carrier 220 and the target 240 may shake, so a base 270 is connected to the bottom of the driving member for keeping the driving member 240, the carrier 220 and the target 210 stably placed on a plane:
the shielding reflector 280 shields neutrons scattered in the process of bombarding the target 210 by the high-current particle beam generated by the linear accelerator 200 and converting the high-current particle beam into high-energy neutron beam inside the shielding reflector 280, and reflects the neutrons back to the moderator 250, and the moderator 250 and the neutrons reflected by the shielding reflector 280 have inelastic collision, so that the high-energy neutron beam loses energy and is moderated to the range of epithermal neutron energy to obtain epithermal neutrons and form the epithermal neutron beam.
The shielding reflector 280 generally refers to a material device having radiation protection and shielding effects and neutron mixed beam filtering and reflecting effects.
Among them, the shielding reflector 280 may include a shielding body 281 and a reflecting body 282:
a shield 281 for preventing neutron radiation scattered by the moderator from interacting with the high energy neutron beam.
A reflector 282 for reflecting neutrons scattered by the moderator upon interaction with the high energy neutron beam back to the moderator, such that the epithermal neutron flux is increased.
In some embodiments, the shield 281 may specifically include a neutron shield and a photon shield.
And the neutron shielding body is used for shielding the neutrons and preventing the neutrons from causing additional irradiation.
And the photon shielding body is used for shielding the photons and preventing the photons from causing additional irradiation.
The shield 281 is outside the reflector 282, and a common material of the shield 281 includes boron-containing polyethylene (with a boron mass fraction of 10%) as an absorption shield for neutrons.
The reflector 282 is inside the shield 281, and the reflector 282 is made of one or more of teflon, beryllium oxide, aluminum oxide, and lead. With the above materials, the reflector 282 has a high elastic scattering cross section and a low absorption cross section within a suitable neutron energy interval.
And a base 270 for keeping the driving member 240, the carrier 220, and the target 210 stably placed on a plane.
If a large amount or part of neutrons are scattered by the target 210 in the process of bombarding the target 210 by the high-current particle beam generated by the linear accelerator 200 and converting the high-energy neutron beam into the high-energy neutron beam, the high-energy neutron beam can be reflected back to the moderator 250 by the shielding reflector 280 for moderation, so that the neutron utilization rate is improved, the flux of thermal neutrons or epithermal neutrons at the beam outlet of the multi-slit collimator 260 of the space division modulation collimation component is as high as possible, and meanwhile, the base 270 can keep the driving component 240, the supporting body 220 and the target 210 stably placed on a plane.
Referring to fig. 3, based on the embodiment corresponding to fig. 1, the neutron beam grid irradiation system provided by the embodiment of the present application may further include a filter 380 and a base 370. The outlet of the moderator 350 is aligned with the filter 380, and thermal neutrons, fast neutrons and gamma rays are generated after or during the moderation process of the moderator, and the generated thermal neutrons, fast neutrons and gamma rays can be absorbed by superficial tissues of the human body and deposit energy, and the dose of the superficial tissues needs to be avoided when deep tumors are treated, so that the thermal neutrons, fast neutrons and gamma rays need to be filtered by the filter. In addition, when the driving member 340 rotates, the driving member 340, the carrier 320 and the target 310 may shake, so a base 370 is connected to the bottom of the driving member 340 for keeping the driving member 340, the carrier 320 and the target 310 stably placed on a plane.
The filter 380 filters unwanted beam components such as thermal neutrons, fast neutrons and gamma rays scattered by the moderator 350 when the epithermal neutron beam is formed, so as to obtain a relatively pure epithermal neutron beam, and the spatial division modulation collimating component multi-slit collimator 360 forms the passing uniform and relatively pure epithermal neutron beam into a grid-type neutron beam.
The filter material has a higher absorption cross section in the energy range of thermal neutrons and fast neutrons, and a smaller absorption cross section in the energy range of epithermal neutrons, so that the flux and fluence of the thermal neutrons and the fast neutrons can be greatly reduced, and the influence on the flux and fluence of the epithermal neutrons is smaller.
Wherein, the filter 380 may specifically include a thermal neutron filter 381, a fast neutron filter 382, and a gamma ray filter 383:
and the thermal neutron filter 381 is used for filtering the thermal neutrons.
And the fast neutron filtering body 382 is used for filtering the fast neutrons.
A gamma ray filter 383 for filtering the gamma ray.
The thermal neutron filter 381 is made of one or more of lithium, boron, and cadmium.
The fast neutron filter 382 is made of nickel.
Wherein, the gamma ray filter 383 is made of one or more of lead and bismuth.
And a base 370 for keeping the driving member 340, the carrier 320 and the target 310 stably placed on a plane.
If thermal neutrons, fast neutrons and gamma rays are generated after or during the slowing down of the slowing-down body 350, the filter 380 can be used to filter unwanted beam components such as thermal neutrons, fast neutrons and gamma rays to obtain a relatively pure epithermal neutron beam, and the base 370 can keep the driving member 340, the supporting body 320 and the target 310 stably placed on a plane.
Referring to fig. 4, based on the embodiment corresponding to fig. 1, the neutron beam grid irradiation system provided by the embodiment of the present application may further include a shielding reflector, a filter, and a base.
The embodiment of the application provides a neutron beam grid irradiation system, wherein a carrier 420 carries at least three targets, each target 410 is uniformly distributed on the carrier 420 by taking the geometric center of the carrier as a circle center, the distances from each target 410 to the geometric center of the carrier 420 are the same, and gaps exist among the targets 410; the driving part 440 drives the carrier 420 to rotate around the bearing 430 through the bearing 430 according to a predetermined rotation frequency, so that each target 410 is aligned with the outlet of the linear accelerator 400 in sequence; the geometric center of the carrier 420 and the geometric center of the bearing are on the same straight line; the exit of the target 410 is aligned with the moderator 450; the exit of the moderator 450 is aligned with the spatially-split modulating collimating component multi-slit collimator 460; the linear accelerator 400 generates a high-current particle beam according to a preset duty ratio, the driving part 440 drives the supporting body 420 through a bearing so that the target 410 is driven to rotate, the extraction frequency of the particle beam generated by the linear accelerator 400 is consistent with the periodic rotation frequency of the target 410, more high-current particle beams interact with the target 410, and the yield and purity of the high-current particle beam converted into the high-energy neutron beam are higher; the moderator 450 interacts with the high-energy neutron beam to moderate the high-energy neutron beam to an epithermal neutron energy range, so as to obtain epithermal neutrons and form the epithermal neutron beam, wherein the epithermal neutron energy range is larger than a first threshold and smaller than a second threshold, the space division modulation collimation component multi-slit collimator 460 converts the passed epithermal neutron beam into a grid-type neutron beam, and the epithermal neutron beam which does not pass is absorbed. In addition, the shielding body 471 of the shielding reflector 470 can be used for preventing neutrons scattered by the moderator 450 when interacting with the high-energy neutron beam from radiating out, the reflector 472 of the shielding reflector 470 is used for reflecting neutrons scattered by the moderator 450 when interacting with the high-energy neutron beam, and the filter 480 is used for filtering thermal neutrons, fast neutrons and gamma rays scattered by the moderator 450 when forming the super-thermal neutron beam, so that the super-thermal neutron beam with relatively pure and uniform components can be obtained. Finally, a base 490 is connected to the driving member 440, so that the driving member 440, the carrier 420 and the target 410 are stably placed on a plane.
It should be noted that, in the present specification, all the embodiments are described in a progressive manner, and the same and similar parts among the embodiments may be referred to each other, and each embodiment focuses on the differences from the other embodiments. Some or all of them can be selected according to actual needs to achieve the purpose of the solution of the embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (14)
1. A neutron capture irradiation system, comprising: the device comprises a linear accelerator, a target, a supporting body, a bearing, a driving component, a slowing body and a space division modulation collimation component multi-slit collimator;
the supporting body is used for supporting at least three target materials, each target material is uniformly distributed on the supporting body by taking the geometric center of the supporting body as a circle center, the distances from each target material to the geometric center of the supporting body are the same, and gaps exist among the target materials;
the driving component drives the supporting body to rotate by taking the bearing as an axis according to a preset rotating frequency through the bearing, so that the targets are aligned with the outlet of the linear accelerator in sequence; the geometric center of the bearing body and the geometric center of the bearing are on the same straight line;
the outlet of the target is aligned with the slowing-down body; the outlet of the slowing-down body is aligned with the multi-slit collimator of the space division modulation collimation component;
the linear accelerator is used for generating a high-current particle beam according to a preset duty ratio;
the target is used for converting the high-current particle beam into a high-energy neutron beam;
the moderating body is used for interacting with the high-energy neutron beam, so that the high-energy neutron beam loses partial energy and is moderated to the energy range of epithermal neutrons to obtain epithermal neutrons and form the epithermal neutron beam; wherein the epithermal neutron energy range is greater than a first threshold and less than a second threshold;
the space division modulation collimation component multi-slit collimator is used for converting the passing epithermal neutron beam flow into a grid-type neutron beam flow and absorbing the non-passing epithermal neutron beam flow.
2. The neutron capture irradiation system of claim 1, wherein the preset rotation frequency is consistent with the preset duty cycle; the preset duty cycle is adjusted according to the preset rotation frequency.
3. The neutron capture irradiation system of claim 1, further comprising:
the base is connected with the driving part;
the base is used for keeping the driving component, the bearing body and the target stably placed on a plane.
4. The neutron capture irradiation system of claim 1, wherein the moderator material is one or more of fluoride, heavy water, polyethylene, and graphite.
5. The neutron capture irradiation system of claim 1, further comprising:
the shielding reflector is wrapped outside the slowing-down body and the target material;
the shielding reflector is used for preventing neutrons scattered by the moderator from radiating out when the moderator interacts with the high-energy neutron beam and reflecting neutrons scattered by the moderator when the moderator interacts with the high-energy neutron beam.
6. The neutron capture irradiation system of claim 5, wherein the shielding reflector comprises a shield and a reflector;
the shielding body is used for preventing neutrons and photons scattered by the moderating body from radiating out when the moderating body interacts with the high-energy neutron beam;
the reflector is used for reflecting neutrons scattered by the moderator when the moderator interacts with the high-energy neutron beam to the moderator, so that the epithermal neutron flux is improved.
7. The neutron capture irradiation system of claim 6, wherein the shield comprises a neutron shield and a photon shield;
the neutron shielding body is used for shielding the neutrons and preventing the neutrons from causing additional irradiation;
the photon shielding body is used for shielding the photons and preventing the photons from causing additional irradiation.
8. The neutron capture irradiation system of claim 6, wherein the shield is a boron-containing polyethylene.
9. The neutron capture irradiation system of claim 6, wherein the reflector material is one or more of polytetrafluoroethylene, beryllium oxide, aluminum oxide, and lead.
10. The neutron capture irradiation system of claim 1, further comprising:
a filter body, an outlet of the moderator body being aligned with the filter body;
the filter is used for filtering thermal neutrons, fast neutrons and gamma rays scattered by the moderator when the moderator forms the epithermal neutron beam to obtain uniform epithermal neutron beam.
11. The neutron capture irradiation system of claim 10, wherein the filter comprises a thermal neutron filter, a fast neutron filter, and a gamma ray filter;
the thermal neutron filtering body is used for filtering the thermal neutrons;
the fast neutron filtering body is used for filtering the fast neutrons;
the gamma ray filter is used for filtering the gamma rays.
12. The neutron capture irradiation system of claim 11,
the thermal neutron filter body is made of one or more of lithium, boron and cadmium;
the fast neutron filter body is made of nickel;
the gamma ray filter body is made of one or more of lead and bismuth.
13. The neutron capture irradiation system of claim 10, comprising:
the space division modulation collimation component multi-slit collimator is specifically used for forming the passing uniform super-thermal neutron beam flow into a grid-type neutron beam flow and absorbing the non-passing super-thermal neutron beam flow.
14. The neutron capture irradiation system of claim 1, wherein the spatially-segmented modulating collimation member multi-slit collimator material is a lithium-containing polyethylene polymer or a boron-containing polyethylene polymer.
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