Ion Source Beam Current Screening and Shaping Device and Method

Abstract

The present invention provides an ion source beam current screening and shaping device and method, belonging to the technical field of beam current processing and control. The device is arranged at the injection end of a linear accelerator. The ion source beam current screening and shaping device includes: an extraction and mixing section and a comprehensive processing section connected in sequence, wherein: the extraction and mixing section includes a focusing solenoid and a dipole magnet. The focusing solenoid is used for focusing and shaping the mixed ion beam extracted from the ion source, and the dipole magnet is used for screening out target particles that meet the specified specific energy and M / Q of the linear accelerator from the mixed ion beam current after focusing and shaping to obtain an initial ion beam current; the comprehensive processing section includes a focusing quadrupole magnet and a processing chamber. The focusing quadrupole magnet is used for adjusting the envelope sizes of the initial ion beam current in at least two directions on the longitudinal section; the processing chamber is used for processing the initial ion beam current into an injection ion beam current that meets the specified emission angle and envelope size of the linear accelerator.

Description

Technical Field

[0001] The present invention relates to the technical field of beam manipulation, and in particular to a beam screening and shaping device and method for a high charge state ECR ion source. Background Art

[0002] The high charge state electron cyclotron resonance ion source is the source of a heavy ion accelerator, providing beams of all particle species for the accelerator. However, due to the unique magnetic field structure of the high charge state electron cyclotron resonance ion source, the profile of the extracted beam is not a regular circle, but an approximately triangular distribution, and the beam spots of some beams are even hollow. For a beam with such a shape, after passing through the matching elements, the distortion is severe. This part of the distorted beam cannot be accelerated by the linear accelerator and will be lost in the linear accelerator, which has a certain impact on the stability and service life of the linear accelerator.

[0003] In the prior art, generally before the ion source beam enters the linear accelerator, the target particles in the ion source beam are first screened, and then the beam parameters are adjusted by the beam matching section to achieve matching with the injection beam parameters of the linear accelerator. However, this method generally requires a long beam line, many beam line beam components, and a high difficulty in beam tuning in the later stage, and is slightly inferior in terms of economy and convenience. At the same time, the long beam line will also cause a certain increase in the beam emittance, which will reduce the utilization efficiency of the beam.

[0004] How to improve the utilization efficiency of high charge state ion beams and reduce the beam loss of the linear accelerator is a technical problem that those skilled in the art urgently need to solve. Summary of the Invention

[0005] Aiming at the problems existing in the prior art, the present invention provides an ion source beam screening and shaping device and method.

[0006] The present invention provides an ion source beam screening and shaping device, which is arranged at the injection end of the linear accelerator. The ion source beam screening and shaping device includes: an extraction and mixing section and a comprehensive processing section connected in sequence, where:

[0007] The extraction and mixing section includes a focusing solenoid and a dipole magnet. The focusing solenoid is used to focus and shape the mixed ion beam extracted from the ion source, and the dipole magnet is used to screen out the target particles that meet the specific energy and M / Q specified by the linear accelerator from the mixed ion beam current after focusing and shaping to obtain an initial ion beam current;

[0008] The comprehensive processing section includes a focusing quadrupole magnet and a processing chamber. The focusing quadrupole magnet is used to adjust the envelope size of the initial ion beam current in at least two directions on the longitudinal section; the processing chamber is used to process the initial ion beam current into an injection ion beam current that meets the emission angle and envelope size specified by the linear accelerator.

[0009] According to an ion source beam screening and shaping device provided by the present invention, the processing chamber includes a beam scraping system:

[0010] The beam scraping system is used to remove particles that do not meet the emission angle from the initial ion beam flow to obtain a first ion beam flow.

[0011] According to an ion source beam screening and shaping device provided by the present invention, the processing chamber further includes a beam cutting system:

[0012] The beam cutting system is used to cut the first ion beam flow into pulse beams of preset time length based on the time structure of the linear accelerator to obtain a second ion beam flow.

[0013] According to an ion source beam screening and shaping device provided by the present invention, the processing chamber further includes a beam matching element arranged after the beam cutting system, wherein:

[0014] The beam matching element is used to adjust the emission angle of the second ion beam based on the emission angle specified by the linear accelerator to obtain the implanted ion beam.

[0015] According to an ion source beam screening and shaping device provided by the present invention, the beam matching element includes at least one focusing element; the focusing element is used to adjust the second ion beam from a divergent state to a convergent state.

[0016] According to an ion source beam screening and shaping device provided by the present invention, the beam matching element also includes a beam detector, which is arranged between each of the focusing elements. The beam detector is used to verify the injected ion beam based on the first condition and the second condition. When the verification result is passed, the injected ion beam is injected into the linear accelerator.

[0017] According to an ion source beam screening and shaping device provided by the present invention, the envelope size is used to characterize the diameter size of the initial ion beam in each direction.

[0018] According to an ion source beam screening and shaping device provided by the present invention, the dipole magnet is an M / Q velocity selector; M is the particle mass specified by the linear accelerator, and Q is the particle charge specified by the linear accelerator.

[0019] According to an ion source beam screening and shaping device provided by the present invention, the mixed ion beam is a high-charge ion source beam.

[0020] The present invention also provides an ion source beam screening and shaping method, which is implemented by using the above-mentioned ion source beam screening and shaping device, comprising:

[0021] Focus and shape the mixed ion beam through the extraction and mixing section, and screen for target particles that meet the specific energy and M / Q requirements of the linear accelerator to obtain an initial ion beam current;

[0022] Based on the comprehensive processing section, process the initial ion beam current into an injection ion beam current that meets the emission angle and envelope size requirements of the linear accelerator;

[0023] The ion source beam current screening and shaping device of the present invention is arranged in the injection section of the linear accelerator and includes an extraction and mixing section and a comprehensive processing section connected in sequence. The extraction and mixing section is used to focus and shape the mixed ion beam extracted from the ion source, and screen for target particles that meet the particle type requirements of the linear accelerator from the focused and shaped mixed ion beam current to obtain an initial ion beam current; the initial ion beam current is processed through the comprehensive processing section. The comprehensive processing section includes a focusing quadrupole magnet and a processing chamber. The focusing quadrupole magnet can adjust the envelope size of the initial ion source beam current in at least two directions in the longitudinal section, and the processing chamber is used to process the initial ion source beam current into an injection ion beam current that meets the beam current envelope size and beam current emission angle requirements of the linear accelerator. The ion source beam current screening and shaping device of the present invention greatly shortens the distance from the ion source to the linear accelerator by compactly arranging the shaping and screening parts together, reduces the emittance growth before injection, improves the utilization efficiency of high-charge-state ion beams, reduces the beam current loss in the linear accelerator, and has very good economy compared with the traditional scheme. Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0025] Figure 1 It is a schematic structural diagram of the ion source beam current screening and shaping device provided by the present invention;

[0026] Figure 2 It is a schematic diagram of the ion source beam current in the transverse and longitudinal directions provided by the present invention;

[0027] Figure 3 It is a schematic flow diagram of the ion source beam current screening and shaping method provided by the present invention. Detailed Embodiments

[0028] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Combine the following Figures 1-3 The ion source beam screening and shaping device and apparatus of the present invention are described.

[0030] Figure 1 Schematic diagram of the structure of the ion source beam screening and shaping device provided by the present invention. Figure 1 As shown, the ion source beam screening and shaping device provided by the embodiment of the present invention includes an extraction mixing section and a comprehensive processing section connected in sequence:

[0031] Specifically, the ion source beam screening and shaping device is arranged at the injection end of the linear accelerator. Before the ion source beam enters the linear accelerator, it needs to pass through the ion source beam screening and shaping device.

[0032] An atom is composed of a nucleus and extranuclear electrons. When one or more of the outer electrons of the nucleus are stripped off, ions are formed. The number of stripped electrons is called the charge state of the ion. An ion source is a device that ionizes neutral atoms or molecules and draws out an ion source beam from them.

[0033] In the embodiment of the present invention, the mixed ion beam extracted from the ion source needs to be screened and shaped according to actual needs before entering the linear accelerator for acceleration. The first part of the ion source beam screening and shaping device is the extraction mixing section.

[0034] The extraction mixing section includes a focusing solenoid and a dipole magnet, which are used to focus and shape the mixed ion source beam extracted from the ion source, and screen the first target particles that meet the first condition to obtain the initial ion source beam;

[0035] Specifically, the extraction mixing section includes a focusing solenoid and a dipole magnet. In the specific implementation, it is first necessary to use the focusing solenoid to use the magnetic field to make the charged particles subject to lateral force, forcing the required charged particles to be close to the central axis to avoid loss during transmission. Further, based on the theoretical beam parameters at the scraping system and the parameters of the mixed ion beam, the focusing solenoid is combined with a dipole magnet and a quadrupole magnet to adjust the envelope size of the beam, so that the envelope and emission angle of the beam at the scraping point are consistent with the theory. In this step, the envelope can be understood as the size of the cross-section of the beam at a certain position in the propagation direction.

[0036] Furthermore, the dipole magnet in the embodiment of the present invention is an M / Q selector. Only the particles in the mixed ion beam set by the linear accelerator that meet the preset mass number and preset charge number set by the linear accelerator can pass through. Based on the dipole magnet, the particles in the mixed ion beam that meet the above conditions can be screened. In addition, it can also be set that only particles of a fixed type in the mixed ion beam can pass through, and the specific setting method is not specifically limited here.

[0037] Through the first part of the ion source beam screening and shaping device, that is, the extraction and mixing section, the mixed ion beam extracted from the ion source can be preliminarily processed, including screening the target particles that meet the preset mass number and preset charge number set by the linear accelerator, and adjusting the triangular distribution of the mixed ion beam to a nearly circular shape. At this time, the mixed ion source beam is processed into an initial ion source beam.

[0038] The comprehensive processing section includes a focusing quadrupole magnet and a processing chamber.

[0039] The focusing quadrupole magnet is used to adjust the envelope sizes of the initial ion source beam in two directions on the longitudinal cross-section; the processing chamber is used to process the initial ion source beam into an injection ion beam that meets the beam envelope and beam emission angle specified by the linear accelerator.

[0040] Specifically, after the mixed ion beam passes through the above-mentioned extraction and mixing section, an initial ion beam is obtained, and then it enters the comprehensive processing section. The comprehensive processing section in the embodiment of the present invention includes a focusing quadrupole magnet and a processing chamber, and the processing chamber further includes a beam scraping system, a beam cutting system, and beam matching elements. They are all compactly arranged together, and multi-dimensional comprehensive processing of the initial ion beam can be completed in the comprehensive processing section to obtain the injection ion beam that is finally to be injected into the linear accelerator.

[0041] Specifically, the focusing quadrupole magnet is used to adjust the envelope sizes of the initial ion source beam in the X and Y directions. Figure 2 is a schematic diagram of the transverse and longitudinal directions of the ion source beam provided by the present invention, as Figure 2 shown:

[0042] The ion source beam after processing is transmitted longitudinally, that is, Figure 2 the Z-axis direction in the left figure. In the embodiment of the present invention, the cross-section perpendicular to the Z direction is defined as the transverse cross-section, and the transverse cross-section includes two directions, X and Y, as Figure 2 shown in the right figure in the middle, which is the longitudinal cross-section, and the settings of the X and Y directions can be clearly defined.

[0043] At a certain moment, the cross-sectional size of the longitudinal section of the ion source beam at a certain moment is the beam envelope. In the embodiment of the present invention, in order to make the longitudinal section of the ion source beam more circular, it is necessary to adjust the envelope size of the initial ion source beam from the X and Y directions, so that the initial ion source beam has substantially the same size in the two directions before entering the beam scraping system and the beam cutting system.

[0044] Furthermore, the initial ion beam current adjusted by the focusing quadrupole magnet is transmitted to the beam scraping system and the beam cutting system.

[0045] Specifically, the scraping beam system is used to scrape off some particles in the initial ion beam, that is, the scraping beam system is used to scrape off particles in the initial ion source beam that do not meet the injection requirements of the linear accelerator. Based on the above-mentioned speed selector, target particles that meet the specific energy and M / Q specified by the linear accelerator are screened from the mixed ion beam. In the scraping beam system, particles in the initial ion beam that do not meet the emission angle specified by the linear accelerator are scraped off. In an embodiment of the present invention, the linear accelerator limits the beam quality of the ion beam passing through the linear accelerator, and the ion source beam quality generally refers to the emission angle of the beam. In an embodiment of the present invention, based on the scraping beam system, particles that do not meet the beam emission angle set by the linear accelerator are scraped off from the initial ion beam. After passing through the scraping beam system, the initial ion beam is processed into a first ion beam.

[0046] Furthermore, the first ion source beam after some particles are scraped off by the beam scraping system also needs to pass through the beam cutting system. In a specific implementation, the ion beam drawn out by the ion source is usually continuous, and the first ion beam in the embodiment of the present invention is also continuous. It is necessary to cut the continuous first ion beam into a pulse beam of a specific time length based on the requirement of setting the time structure of the linear acceleration. After the first ion beam is processed by the beam scraping system and the beam cutting system, a second ion beam is obtained after some particles are scraped off and the pulse beam length is adjusted.

[0047] The ion source beam screening and shaping device of the embodiment of the present invention is arranged in the injection section of the linear accelerator, and includes an extraction mixing section and a comprehensive processing section connected in sequence, wherein: the extraction mixing section includes a focusing solenoid and a dipole magnet, which are used to focus and shape the mixed ion source beam extracted from the ion source, and screen target particles that meet the specific energy and M / Q specified by the linear accelerator to obtain an initial ion beam, which is an ion beam screened by a velocity selector and focused and shaped;

[0048] Then the initial ion beam is transmitted to the comprehensive processing section, which includes a focusing quadrupole magnet, a beam scraping system and a beam cutting system, and is used to select an injection ion beam that meets the emission angle and envelope size specified by the linear accelerator from the initial ion beam obtained by the extraction mixing section based on the first preset parameters of the linear accelerator to obtain the injection ion beam. The envelope size and emission angle of the initial ion beam can be adjusted in the comprehensive processing section.

[0049] The ion source beam screening and shaping device of the present invention processes the initial ion beam after preliminary screening and shaping by compactly arranging a focusing quadrupole magnet, a beam scraping system and a beam cutting system, and screens out an injection ion beam that meets the requirements of a linear accelerator, thereby greatly shortening the distance from the ion source to the linear accelerator, reducing the emittance growth before injection, improving the utilization efficiency of high-charge state ion beams, and reducing beam losses in the linear accelerator. At the same time, compared with traditional solutions, it has very good economy.

[0050] Optionally, according to an ion source beam screening and shaping device provided by an embodiment of the present invention, the processing chamber includes a beam scraping system:

[0051] The beam scraping system is used to remove particles that do not meet the beam emittance from the initial ion beam flow to obtain a first ion beam flow.

[0052] Specifically, the scraping beam system is used to scrape off some particles in the initial ion source beam, that is, the scraping beam system is used to scrape off particles in the initial ion source beam that do not meet the injection requirements of the linear accelerator. Based on the above-mentioned speed selector, the target particles that meet the specific energy and M / Q specified by the linear accelerator are screened from the mixed ion source beam. In the scraping beam system, the injected ion beam that does not meet the emission angle and envelope size specified by the linear accelerator is scraped off from the initial ion beam. In an embodiment of the present invention, the emission angle and envelope size specified by the linear accelerator limit the quality of the ion source beam passing through the linear accelerator. The ion source beam quality generally refers to the emittance of the beam. In an embodiment of the present invention, based on the scraping beam system, particles that do not meet the beam emittance set by the linear accelerator are scraped off from the initial ion beam. After passing through the scraping beam system, the initial ion source beam is processed into a first ion beam.

[0053] Optionally, according to an ion source beam screening and shaping device provided by an embodiment of the present invention, the processing chamber further includes a beam cutting system:

[0054] The beam cutting system is used to cut the first ion beam flow into pulse beams of preset time length based on the time structure of the linear accelerator to obtain a second ion beam flow.

[0055] Specifically, the first ion beam flow after some particles are scraped off by the beam scraping system also needs to pass through the beam cutting system. In a specific implementation, the ion beam flow drawn out by the ion source is usually continuous, and the first ion beam flow in the embodiment of the present invention is also continuous. It is necessary to cut the continuous first ion beam flow into a pulse beam of a specific time length based on the requirement of setting the time structure of the linear acceleration. After the first ion beam flow is processed by the beam scraping system and the beam cutting system, after some particles are scraped off and the pulse beam length is adjusted, a second ion beam flow is obtained.

[0056] Optionally, according to an ion source beam screening and shaping device provided by an embodiment of the present invention, the processing chamber further comprises a beam matching element arranged after the beam cutting system, wherein:

[0057] The beam matching element is used to adjust the emission angle of the second ion source beam based on the emission angle and envelope size specified by the linear accelerator to obtain the implanted ion beam.

[0058] Specifically, the beam matching element can adjust the beam parameters of the second ion beam based on the emission angle and envelope size specified by the linear accelerator. The beam matching element can not only adjust the emission angle of the second ion beam, but also further refine and adjust the envelope of the second ion beam, that is, the cross-sectional diameter of the injected ion beam, and finally obtain the injected ion beam, so that the injected ion beam can be better matched with the linear accelerator.

[0059] The ion source beam screening and shaping device provided by the embodiment of the present invention comprises an extraction mixing section and a comprehensive processing section connected in sequence, wherein the extraction mixing section is used to focus and shape the mixed ion source beam extracted from the ion source, and to screen target particles that meet the particle types specified by the linear accelerator from the mixed ion source beam after focusing and shaping, so as to obtain an initial ion source beam; the initial ion source beam is processed by the comprehensive processing section, and the comprehensive processing section comprises a focusing quadrupole magnet and a processing chamber, the focusing quadrupole magnet can adjust the envelope size of the initial ion source beam in two directions on the longitudinal section, and the processing chamber is used to process the initial ion source beam into an injection ion beam that meets the beam envelope size and beam emission angle specified by the linear accelerator. The ion source beam screening and shaping device of the present invention greatly shortens the distance from the ion source to the linear accelerator by compactly arranging the shaping and screening parts together, reduces the emittance growth before injection, improves the utilization efficiency of high-charge ion beams, reduces the beam loss in the linear accelerator, and has very good economy compared with traditional solutions.

[0060] Optionally, for an ion source beam current screening and shaping device provided by an embodiment of the present invention, the beam current matching element further includes a beam current detector, the beam current detector is arranged between each of the focusing elements, and the beam current detector is used to verify the injected ion beam current based on a first condition and a second condition, and in the case where the verification result passes, inject the injected ion beam current into the linear accelerator.

[0061] Specifically, in some embodiments, the beam current matching element further includes a beam current detector, and the beam current detector is selectively arranged between each of the focusing elements.

[0062] The beam current detector is used to verify the injected ion beam current based on the specific energy and M / Q specified by the linear accelerator, and the emission angle and envelope size specified by the linear accelerator, and in the case where the verification result passes, inject the injected ion beam current into the linear accelerator.

[0063] The beam current detector in the beam current detection section can also be regarded as a beam current diagnostor, and based on the first condition and the second condition of linear acceleration, perform a pre-injection check on the injected ion beam current that is about to be injected into the linear accelerator, that is, verify whether the injected ion beam current meets the requirements of the linear accelerator, and in the case where the verification result passes, inject the injected ion beam current into the linear accelerator. On the contrary, in the case where the verification result fails, it is necessary to return to the above device for further refinement and adjustment.

[0064] The ion source beam current screening and shaping device according to the embodiment of the present invention verifies the injected ion beam current that has undergone pre-treatment through a beam current detector, and only injects the injected ion beam current into the linear accelerator after the verification passes, further improving the accuracy of ion beam current processing.

[0065] Optionally, for an ion source beam current screening and shaping device provided by an embodiment of the present invention, the beam current matching element includes at least one focusing element; the focusing element is used to adjust the second ion beam current from a divergent state to a convergent state.

[0066] Specifically, the injected ion beam current obtained based on the above steps is in a divergent state and needs to be constrained and shaped. The beam current matching element includes at least one focusing element, that is, one or more focusing elements, and the focusing element is used to adjust the second ion beam current from a divergent state to a convergent state to meet the injection conditions of the linear accelerator.

[0067] Optionally, for the ion source beam current screening and shaping device provided by an embodiment of the present invention, the envelope size is used to characterize the diameter size of each direction of the initial ion source beam current.

[0068] Specifically, as described above Figure 2As shown, the ion source beam current after being processed is transmitted in the longitudinal direction, that is, Figure 2 the Z-axis direction in the left figure. In the embodiments of the present invention, a plane perpendicular to the Z direction is defined as the transverse direction, and the transverse direction includes two directions, X and Y, as Figure 2 shown in the right figure. It is the transverse direction of the beam current transmission, and the settings of the X and Y directions can be clearly defined.

[0069] At a certain moment, the transverse size of the ion source beam current at a moment is the beam envelope. In the embodiments of the present invention, in order to make the longitudinal section of the ion source beam current more conform to a circle, it is necessary to adjust the envelope size of the initial ion source beam current in both the X and Y directions so that the sizes of the initial ion source beam current in the two transverse directions remain basically the same before entering the beam scraping system and the beam cutting system.

[0070] Furthermore, the initial ion source beam current adjusted by the focusing quadrupole magnet is transmitted into the beam scraping system and the beam cutting system to obtain the injected ion beam current.

[0071] The ion source beam current screening and shaping device in the embodiments of the present invention is arranged in the injection section of the linear accelerator, and transmits the initial ion source beam current into the comprehensive processing section. The comprehensive processing section includes a focusing quadrupole magnet, a beam scraping system and a beam cutting system, and is used to screen second target particles that meet the second condition from the initial ion source beam current obtained after being processed by the extraction and mixing section based on the first preset parameter of the linear accelerator to obtain the injected ion beam current. In the comprehensive processing section, the envelope size and emission angle of the initial ion source beam current can be adjusted.

[0072] Optionally, according to an ion source beam current screening and shaping device provided by the present invention, the dipole magnet is an M / Q velocity selector; M is the particle mass number specified by the linear accelerator, and Q is the particle charge number specified by the linear accelerator.

[0073] Specifically, the dipole magnet in the embodiments of the present invention is an M / Q selector. For the above-mentioned first condition, that is, the first condition set by the linear accelerator, only the particles in the mixed ion beam that meet the preset mass number and preset charge number set by the linear accelerator can pass through. Based on the dipole magnet, the particles that meet the first condition in the mixed ion beam can be screened. In addition, it can also be set that only particles of a fixed type in the mixed ion beam can pass through, and the specific setting method is not specifically limited here.

[0074] Optionally, according to a high-charge-state ECR ion source beam current screening and shaping device provided by the present invention, the mixed ion source beam current is a high-charge-state ion source beam current.

[0075] Figure 3 is a schematic flowchart of the ion source beam current screening and shaping method provided by the present invention, as Figure 3As shown, the ion source beam screening and shaping method provided by the embodiment of the present invention comprises the following steps:

[0076] Step 310, focusing and shaping the mixed ion beam through the extraction mixing section, and selecting target particles that meet the specific energy and M / Q specified by the linear accelerator to obtain an initial ion beam flow;

[0077] Specifically, it should be noted that the ion source beam screening and shaping method of the embodiment of the present invention is implemented based on the above-mentioned ion source beam screening and shaping device.

[0078] In this step, the extraction mixing section includes a focusing solenoid and a dipole magnet. In the specific implementation, first, the focusing solenoid is used to use the magnetic field to make the charged particles subject to lateral force, forcing the required charged particles to be close to the central axis to avoid loss during transmission. Further, based on the theoretical beam parameters at the scraping system and the parameters of the mixed ion beam, the focusing solenoid is combined with a dipole magnet and a quadrupole magnet to adjust the envelope size of the beam, so that the envelope and emission angle of the beam at the scraping point are consistent with the theory. In this step, the envelope can be understood as the diameter size of the cross-section of the mixed ion source beam at a certain position in the propagation direction.

[0079] Furthermore, the dipole magnet in the embodiment of the present invention is an M / Q selector. The above-mentioned first condition, i.e., the first condition set by the linear accelerator, is that only particles in the mixed ion beam that meet the preset mass number and preset charge number set by the linear accelerator can pass through. Through the first part of the ion source beam screening and shaping device, i.e., the extraction mixing section, the mixed ion source beam extracted from the ion source can be preliminarily processed, including screening particles that meet the first condition, adjusting the triangularly distributed mixed ion beam to a nearly circular shape, and obtaining the initial ion source beam based on the mixed ion source beam.

[0080] Step 320: Based on the comprehensive processing section, the initial ion beam is processed into an injected ion beam that meets the emission angle and envelope size specified by the linear accelerator; the second condition is the beam emission angle and envelope size specified by the linear accelerator.

[0081] Specifically, in this step, the integrated processing section includes a focusing quadrupole magnet and a processing chamber.

[0082] The focusing quadrupole magnet is used to adjust the envelope size of the initial ion source beam in two lateral directions; the processing chamber is used to process the initial ion source beam into an injected ion beam that meets a second condition; the second condition is the beam envelope size and beam emission angle specified by the linear accelerator.

[0083] Specifically, after the mixed ion source beam passes through the above-mentioned extraction mixing section, an initial ion source beam is obtained, and then enters the comprehensive processing section. The comprehensive processing section in the embodiment of the present invention includes a focusing quadrupole magnet and a processing chamber, and the processing chamber includes a beam scraping system, a beam cutting system and a beam matching element, which are compactly arranged together. In the comprehensive processing section, multi-dimensional comprehensive processing of the initial ion source beam can be completed to obtain the injection ion beam to be finally injected into the linear accelerator.

[0084] Specifically, the focusing quadrupole magnet is used to adjust the envelope size of the initial ion source beam in the X and Y directions.

[0085] At a certain moment, the transverse cross-sectional dimension of the ion source beam at a certain moment is the beam envelope. In the embodiment of the present invention, in order to make the transverse distribution of the ion source beam closer to a circle, it is necessary to adjust the envelope dimension of the initial ion source beam from the X and Y directions, so that the dimensions of the initial ion source beam in the two transverse directions remain basically consistent before entering the beam scraping system and the beam cutting system.

[0086] Furthermore, the initial ion source beam adjusted by the focusing quadrupole magnet is transmitted to the beam scraping system and the beam cutting system.

[0087] Specifically, the scraping beam system is used to scrape off some particles in the initial ion source beam, that is, the scraping beam system is used to scrape off particles in the initial ion source beam that do not meet the injection requirements of the linear accelerator. Based on the above-mentioned speed selector, particles that meet the first condition are screened from the mixed ion source beam, and in the scraping beam system, particles in the initial ion source beam that do not meet the second condition of the linear accelerator are scraped off. In an embodiment of the present invention, the second condition limits the beam quality of the ion source beam passing through the linear accelerator, and the ion source beam quality generally refers to the emittance of the beam. In an embodiment of the present invention, based on the scraping beam system, particles that do not meet the beam emittance set by the linear accelerator are scraped off from the initial ion source beam. After passing through the scraping beam system, the initial ion source beam is processed into a first ion source beam.

[0088] Furthermore, the first ion source beam after some particles are scraped off by the beam scraping system also needs to pass through the beam cutting system. In a specific implementation, the ion source beam drawn out through the ion source is usually continuous. The first ion source beam in the embodiment of the present invention is also continuous. It is necessary to cut the continuous first ion source beam into a pulse beam of a specific time length based on the requirement of setting the time structure of the linear acceleration. After the first ion source beam is processed by the beam scraping system and the beam cutting system, after some particles are scraped off and the pulse beam length is adjusted, a second ion source beam is obtained.

[0089] Further, the processing chamber further includes a beam matching element disposed after the beam cutting system. The beam matching element is configured to adjust the emission angle of the second ion source beam based on a second condition number to obtain an injected ion beam.

[0090] Specifically, the beam matching element can adjust the beam parameters of the second ion source beam based on a second condition of the linear accelerator. The second condition may include the limitation of the emission angle of the injected ion beam by the linear accelerator. The beam matching element can not only adjust the emission angle of the second ion source beam, but also further refine the adjustment of the envelope size of the second ion source beam, that is, the transverse size of the injected ion beam, and finally obtain the injected ion beam, so that the injected ion beam can be better matched with the linear accelerator.

[0091] Step 330: Verify the injected ion beam based on the beam detector. When the verification result passes, inject the injected ion beam into the linear accelerator.

[0092] Specifically, the beam detector is configured to verify the injected ion beam based on the regulations of the linear accelerator. When the verification result passes, inject the injected ion beam into the linear accelerator.

[0093] The beam detector is configured to verify the injected ion beam based on the first condition and the second condition. When the verification result passes, inject the injected ion beam into the linear accelerator.

[0094] The beam detector in the beam detection section can also be regarded as a beam diagnostic device. Based on the first condition and the second condition of the linear acceleration, it performs pre-injection inspection on the injected ion beam that is about to be injected into the linear accelerator, that is, verifies whether the injected ion beam meets the requirements of the linear accelerator. When the verification result passes, inject the injected ion beam into the linear accelerator. In contrast, when the verification result fails, it is necessary to return to the above device for further refinement adjustment.

[0095] In the ion source beam screening and shaping method according to the embodiment of the present invention, the solenoid and the dipole magnet are used in the extraction and mixing section to adjust the beam shape, improve the symmetry of the beam in the X and Y directions, and compactly arrange the beam scraping system and the beam cutting system together. With a very compact structure, while realizing particle selection, it also realizes the transverse shaping and longitudinal modulation of the beam, greatly shortening the distance from the ion source to the linear accelerator, reducing the emittance growth before injection, improving the utilization efficiency of high-charge-state ion beams, reducing the beam loss in the linear accelerator, and having very good economy compared with the traditional scheme.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. An ion source beam screening and shaping device, arranged at the injection end of a linear accelerator, characterized in that: The ion source beam screening and shaping device comprises: an extraction mixing section and a comprehensive processing section connected in sequence, wherein: The extraction mixing section includes a focusing solenoid and a dipole magnet, wherein the focusing solenoid is used to focus and shape the mixed ion beam extracted from the ion source, and the dipole magnet is used to screen target particles that meet the specific energy and M / Q specified by the linear accelerator from the mixed ion beam after focusing and shaping, so as to obtain an initial ion beam; The comprehensive processing section includes a focusing quadrupole magnet and a processing chamber, wherein the focusing quadrupole magnet is used to adjust the envelope size of the initial ion beam in at least two directions on the longitudinal section; the processing chamber is used to process the initial ion beam into an injection ion beam that meets the emission angle and envelope size specified by the linear accelerator; The processing chamber includes a beam scraping system and a beam cutting system; The beam scraping system is used to remove particles that do not meet the emission angle from the initial ion beam flow to obtain a first ion beam flow; The beam cutting system is used to cut the first ion beam flow into pulse beams of preset time length based on the time structure of the linear accelerator to obtain a second ion beam flow.

2. The ion source beam screening and shaping device according to claim 1, characterized in that: The processing chamber further comprises a beam matching element disposed after the beam cutting system, wherein: The beam matching element is used to adjust the emission angle of the second ion beam based on the emission angle specified by the linear accelerator to obtain the implanted ion beam.

3. The ion source beam screening and shaping device according to claim 2, characterized in that: The beam matching element includes at least one focusing element; the focusing element is used to adjust the second ion beam from a divergent state to a convergent state.

4. The ion source beam screening and shaping device according to claim 3, characterized in that: The beam matching element also includes a beam detector, which is arranged between each of the focusing elements. The beam detector is used to verify the injection ion beam based on the first condition and the second condition. When the verification result is passed, the injection ion beam is injected into the linear accelerator.

5. The ion source beam screening and shaping device according to claim 1, characterized in that: The envelope size is used to characterize the diameter size of the initial ion beam in each direction.

6. The ion source beam screening and shaping device according to claim 1, characterized in that: The dipole magnet is an M / Q speed selector; M is the particle mass specified by the linear accelerator, and Q is the particle charge specified by the linear accelerator.

7. The ion source beam screening and shaping device according to claim 1, characterized in that: The mixed ion beam is a high-charge ion source beam.

8. An ion source beam screening and shaping method, implemented by using the ion source beam screening and shaping device according to any one of claims 1 to 7, characterized in that: include: The mixed ion beam is focused and shaped by the extraction mixing section, and target particles meeting the specific energy and M / Q specified by the linear accelerator are selected to obtain an initial ion beam flow; Based on the comprehensive processing section, the initial ion beam flow is processed into an injection ion beam flow that meets the emission angle and envelope size specified by the linear accelerator; The implanted ion beam is verified based on the beam detector, and when the verification result is passed, the implanted ion beam is injected into the linear accelerator.

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