CN115279008A - Medical ion linear accelerator - Google Patents

Abstract

The present disclosure provides a medical ion linear accelerator, including: the system comprises an ion source, a low-energy beam transport line, a radio-frequency quadrupole field linear accelerator, a first intermediate energy beam transport line, a first drift tube linear accelerator, a second intermediate energy beam transport line, a second drift tube linear accelerator and a high-energy beam transport line which are connected in sequence; the ion source generates particle beams which sequentially pass through a low-energy beam transport line, a radio-frequency quadrupole field linear accelerator, a first intermediate energy beam transport line, a first drift tube linear accelerator, a second intermediate energy beam transport line, a second drift tube linear accelerator and a high-energy beam transport line and alternately pass through multiple phase space matching processing and multiple pre-acceleration processing, so that the finally output particle beams can be successfully injected into an inlet of the synchrotron. The high-frequency vacuum resonant cavity in the radio-frequency quadrupole field linear accelerator adopts an H-mode four-rod structure, and the cavity and the accelerating structure are separated without welding, so that the risk of cavity deformation caused by the welding process is reduced, and the processing cost is reduced.

Description

A medical ion linear accelerator

technical field

The disclosure relates to the technical field of cancer treatment instruments, in particular to a medical ion linear accelerator.

Background technique

The linear accelerator was developed in the 1920s and 1930s. It uses a radio frequency electric field to accelerate a beam of charged particles moving along a straight line to a higher energy. Charged particle beams such as protons and heavy ions have Bragg peak effects, so they are more and more widely used in the medical field. As one of the most effective cancer treatment methods in the world today, proton and heavy ion radiation therapy has the characteristics of precise action position and obvious therapeutic effect. The ion linear accelerator with an output energy range of 4MeV/u-7MeV/u has a beam current With the characteristics of high intensity and good beam quality, it is the most suitable equipment as the front-end injector of the synchrotron.

The ion linac in the prior art generally adopts the combination of radio frequency quadrupole field linac (Radio Frequency Quadrupole, RFQ) and drift tube linac (Drift Tube Linac, DTL). Combination with Alvarez-type drift tube linear accelerator, combination of four-wing radio frequency quadrupole field linear accelerator RFQ and drift tube linear accelerator IH-DTL, combination of four-rod radio frequency quadrupole field linear accelerator RFQ and Alvarez type drift tube linear accelerator And the combination of four-rod radio frequency quadrupole field linear accelerator RFQ and drift tube linear accelerator IH-DTL. These combinations use the radio frequency quadrupole field linear accelerator RFQ for pre-acceleration, and then use the drift tube linear accelerator DTL to accelerate to the design energy. To achieve the requirements of compact overall structure of linear accelerator, short cavity length and high transmission efficiency.

However, the four-wing type radio frequency quadrupole field linear accelerator RFQ in the prior art often has the adjacent mode spacing too close, resulting in poor electrical stability of the four wing type radio frequency quadrupole field linear accelerator RFQ, and the frequency and electric field distribution are sensitive to external disturbances. and other defects. However, the four-rod radio frequency quadrupole field linear accelerator RFQ has shortcomings such as small electrodes and complicated water cooling of the electrodes. Alvarez-type drift tube linear accelerators are used in several traditional drift tube linear accelerator solutions. Since magnets need to be installed in the electrode drift tubes, the installation process and alignment technology of the magnets are difficult and costly.

Contents of the invention

In order to solve the above problems in the prior art, the present disclosure provides a medical ion linear accelerator, the radio frequency quadrupole field accelerator adopts the radio frequency quadrupole field linear accelerator IH-RFQ, the high The high-frequency vacuum resonator adopts H-mode multi-rod structure, which has better mechanical strength and electrical stability than the four-wing radio frequency quadrupole field linear accelerator RFQ. At the same time, due to the H-mode in the high-frequency vacuum resonator, the shunt impedance and acceleration gradient are also higher than those of the four-rod radio frequency quadrupole linear accelerator RFQ.

The present disclosure provides a medical ion linear accelerator, including: sequentially connected ion sources, low-energy beam transport lines, radio frequency quadrupole field linear accelerators, first medium-energy beam transport lines, first drift tube linear accelerators, The second medium-energy beam delivery line, the second drift tube linear accelerator, and the high-energy beam delivery line; wherein, the radio frequency quadrupole field linear accelerator includes: a first high-frequency vacuum resonant cavity; wherein, the first high-frequency vacuum resonator The cavity adopts H-mode multi-rod structure, including the first cavity, the second cavity and the third cavity; wherein, the second cavity is arranged between the first cavity and the third cavity, and is connected with the first cavity The body and the third cavity form a sealed structure, and the second cavity includes: two ridge structures and four rod-shaped accelerating electrodes oppositely arranged; two rod-shaped accelerating electrodes in the four rod-shaped accelerating electrodes and the first ridge structure The other two rod-shaped accelerating electrodes are connected to the second ridge structure.

Further, the rod-shaped accelerating electrodes in the four rod-shaped accelerating electrodes are arranged in pairs, wherein the two rod-shaped accelerating electrodes distributed in the vertical direction are connected to the first ridge structure, and the two rod-shaped accelerating electrodes distributed in the horizontal direction Connect with the second ridge structure.

Further, both the first drift tube linear accelerator and the second drift tube linear accelerator include: a second high-frequency vacuum resonant cavity; wherein, the second high-frequency vacuum resonant cavity includes: a fourth cavity, a fifth cavity and a sixth cavity A cavity, wherein the fifth cavity is disposed between the fourth cavity and the sixth cavity, and forms a sealing structure with the fourth cavity and the sixth cavity, and the fifth cavity includes: two opposite ridges structure and a plurality of drift tubes, half of the drift tubes in the plurality of drift tubes are connected to the third ridge structure, and the other half of the drift tubes are connected to the fourth ridge structure.

Further, a plurality of drift tubes are alternately connected to the third ridge structure and the fourth ridge structure through the drift tube support seat, so that the interior of the second high-frequency vacuum resonator is divided into a plurality of alternate longitudinal channels along the advancing direction of the incident particle beam. Focusing segment and transverse focusing segment.

Further, the fourth cavity includes: a second left cavity cover, two adjustable tuners and a fixed tuner, the two adjustable tuners and the fixed tuner are respectively arranged on the outer surface of the left cavity cover; the sixth cavity It includes: a second right chamber cover, a power coupler, a power extractor and a vacuum port, and the power coupler, power extractor and vacuum port are respectively arranged on the outer surface of the right chamber cover.

Further, the first cavity includes: a first left cavity cover, two adjustable tuners and a fixed tuner; the two adjustable tuners and the fixed tuner are respectively arranged on the outer surface of the first left cavity cover; the third The chamber body includes: a first right chamber cover, a power coupler, a power extractor and a vacuum port, and the power coupler, power extractor and vacuum port are respectively arranged on the outer surface of the first right chamber cover.

Further, the medical ion linear accelerator also includes: a power source and a distributed RF power distribution system, the first output end of which is connected to an input end of the first drift tube linear accelerator, and the second output end is connected to an input end of the second drift tube linear accelerator. Connected to an input end of the first drift tube linear accelerator and the power of the high frequency vacuum resonant cavity of the second drift tube linear accelerator is adjusted.

Further, the medical ion linear accelerator also includes: a first integrated beam diagnostic component, used to monitor the state of the particle beam output from the low-energy beam transport line; a second integrated beam diagnostic component, used to monitor the first medium-energy beam The state of the particle beam output by the flow transport line; the third integrated beam diagnostic component is used to monitor the state of the particle beam output by the second energy beam transport line.

Further, the first medium-energy beam transport line and the second medium-energy beam transport line both include: multiple quadrupole magnets, and the multiple quadrupole magnets converge the particle beams on the beam transport line into a horizontal Symmetrical and focused particle beams.

Further, the radio frequency quadrupole field linear accelerator accelerates the particle beam output from the low-energy beam transport line to the first preset energy, and the first drift tube linear accelerator accelerates the particle beam output from the first medium-energy beam transport line The flow is accelerated to the second preset energy, and the second drift tube linear accelerator accelerates the particle beam outputted through the second medium-energy beam transport line to the third preset energy; wherein, the first preset energy, the second preset energy The preset energy and the third preset energy are different in size.

The embodiment of the present disclosure provides a medical ion linear accelerator, which adopts the radio frequency quadrupole field linear accelerator IH-RFQ through the radio frequency quadrupole field linear accelerator RFQ, and the cylindrical high frequency vacuum resonant cavity belongs to the H-mode four-rod structure, that is, the cylindrical Four rod-shaped accelerating electrodes are arranged in a cylindrical high-frequency vacuum resonator, and a pair of ridge structures are arranged vertically and symmetrically in a cylindrical high-frequency vacuum resonator. The first ridge structure on the upper part and two of the four rod-shaped accelerating electrodes The accelerating electrodes are connected, and the second ridge structure at the lower part is connected with two accelerating electrodes in the four accelerating electrodes. The high-frequency vacuum resonant cavity of the radio frequency quadrupole field linear accelerator IH-RFQ adopts a left, middle and right three-layer cavity processing structure, which separates the cavity from the accelerating structure and ensures the vacuum through mechanical connection. The high-frequency vacuum resonant cavity does not require welding, which reduces the risk of cavity deformation caused by the welding process and reduces processing costs. At the same time, when the acceleration structure in the radio frequency quadrupole field linear accelerator IH-RFQ fails, the middle cavity and the acceleration structure can be easily replaced.

Description of drawings

For a more complete understanding of the present disclosure and its advantages, reference should now be made to the following description taken in conjunction with the accompanying drawings, in which:

Fig. 1 schematically shows a schematic cross-sectional view of a medical ion linear accelerator according to an embodiment of the present disclosure;

Fig. 2 schematically shows a schematic structural diagram of a radio frequency quadrupole field linear accelerator according to an embodiment of the present disclosure;

FIG. 3 schematically shows a schematic diagram of the installed structure of a radio frequency quadrupole field linear accelerator according to an embodiment of the present disclosure;

Fig. 4 schematically shows a perspective view of a second cavity according to an embodiment of the present disclosure;

Fig. 5 schematically shows a front view of a second cavity according to an embodiment of the present disclosure;

Fig. 6 schematically shows a schematic diagram of installation positions of four rod-shaped accelerating electrodes in a second cavity according to an embodiment of the present disclosure;

Fig. 7 schematically shows a schematic structural diagram of a first drift tube linear accelerator according to an embodiment of the present disclosure;

Fig. 8 schematically shows a perspective view of a fifth cavity according to an embodiment of the present disclosure;

Fig. 9 schematically shows a front view of a fifth cavity according to an embodiment of the present disclosure.

Detailed ways

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. It should be understood, however, that these descriptions are exemplary only, and are not intended to limit the scope of the present disclosure. In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the present disclosure. It may be evident, however, that one or more embodiments may be practiced without these specific details. Also, in the following description, descriptions of well-known structures and techniques are omitted to avoid unnecessarily obscuring the concepts of the present disclosure.

The terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting of the present disclosure. The terms "comprising", "comprising", etc. used herein indicate the presence of stated features, steps, operations and/or components, but do not exclude the presence or addition of one or more other features, steps, operations or components.

All terms (including technical and scientific terms) used herein have the meaning commonly understood by one of ordinary skill in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted to have a meaning consistent with the context of this specification, and not be interpreted in an idealized or overly rigid manner.

Fig. 1 schematically shows a schematic diagram of a medical ion linear accelerator according to an embodiment of the present disclosure.

As shown in Figure 1, the medical ion linear accelerator 100 includes: an ion source 10, a low-energy beam transport line 20, a radio frequency quadrupole field linear accelerator 30, a first medium-energy beam transport line 40, and a first medium-energy beam transport line 40 connected in sequence. A drift tube linac 50 , a second medium energy beam delivery line 60 , a second drift tube linac 70 and a high energy beam delivery line 80 .

The ion source 10 includes a high-voltage extraction electrode, which is used to generate a high-charge state high-intensity particle beam, and extract the particle beam to a low-energy beam transport line 20 . In an embodiment of the present disclosure, the high-intensity particle beam generated by the ion source 1 may be protons, ¹² C ⁴⁺ particles, and the like.

The low-energy beam transport line 20 is connected to the output end of the ion source 10 and arranged on the particle extraction path. In the embodiment of the present disclosure, the low-energy beam delivery line 20 includes: a solenoid, a correction magnet for beam adjustment, a quadrupole magnet for lateral focusing, and an auxiliary system (such as a vacuum pump), etc., which are used for The charged particle beam extracted from the ion source 10 is subjected to phase space matching processing to make it match the requirements of the input end of the radio frequency quadrupole field linear accelerator IH-RFQ 30 on the phase space of the beam.

The radio frequency quadrupole field linear accelerator IH-RFQ 30, its input terminal is connected with the outlet of the low-energy beam transport line 20, and is used to pre-accelerate the particle beam output by the low-energy beam transport line 20 for the first time, so that the low-energy beam transport line The particle beam output by the beam transport line 20 is accelerated to a first preset energy. In the embodiment of the present disclosure, if the particle beam is proton, the first preset energy may be 2.5-4 MeV; if the particle beam is ¹² C ⁴⁺ particles, the first preset energy may be 400KeV/u-800KeV /u.

According to an embodiment of the present disclosure, as shown in FIGS. 2 and 3 , the radio frequency quadrupole field linear accelerator IH-RFQ 30 includes a first high-frequency vacuum resonator, and the first high-frequency vacuum resonator adopts an H-mode multi-rod structure, It specifically includes: a first cavity 310 , a second cavity 320 and a third cavity 330 . Wherein, the second cavity 320 is disposed between the first cavity 310 and the third cavity 330 , and forms a sealing structure with the first cavity 310 and the third cavity 330 .

Specifically, as shown in FIG. 2 , the first cavity 310 includes: a first left cavity cover 311 , two adjustable tuners 312 and a fixed tuner 313 . Wherein, two adjustable tuners 312 and fixed tuner 313 are respectively arranged on the outer surface of the first left chamber cover 311, and the two adjustable tuners 312 are used for real-time monitoring of the radio frequency quadrupole field linear accelerator IH-RFQ 30. The cavity frequency, field distribution, etc. are adjusted, and the fixed tuner 313 is used for fixed tuning of the cavity frequency in the radio frequency quadrupole field linear accelerator IH-RFQ 30 .

Specifically, as shown in FIGS. 4 and 5 , the second cavity 320 includes: an outer shell 321 , a first ridge structure 322 , a second ridge structure 323 , four rod-shaped accelerating electrodes 324 and a plurality of electrode support rods 325 . Wherein, the first ridge structure 322 and the second ridge structure 323 are arranged on the inner surface of the outer shell 321 oppositely, and the four rod-shaped accelerating electrodes 324 are respectively connected to the first ridge structure 322 and the second ridge structure 323 through a plurality of electrode support rods 325. Connect, and replace the accelerating electrode as needed. Preferably, the rod-shaped accelerating electrodes among the four rod-shaped accelerating electrodes 324 are arranged in pairs. Wherein, two rod-shaped accelerating electrodes distributed in the vertical direction are connected to the first ridge structure, and two rod-shaped accelerating electrodes distributed in the horizontal direction are connected to the second ridge structure. For example, as shown in Figure 6, two rod-shaped accelerating electrodes 3241 distributed in the vertical direction are connected to the first ridge structure 322, and two rod-shaped accelerating electrodes 3242 distributed in the horizontal direction are connected to the second ridge structure 323; also can.

Specifically, as shown in FIG. 2 , the third chamber body 330 includes: a first right chamber cover 331 , a power coupler 332 , a power extractor 333 and a vacuum port. Wherein, the power coupler 332 , the power extractor 333 and the vacuum port are respectively arranged on the outer surface of the first right chamber cover 331 through flanges. The power coupler 332 is used to receive the power of the radio frequency power source, so that the resonant cavity of the radio frequency quadrupole field linear accelerator IH-RFQ 30 is in a resonant state. The power extractor 333 is used to provide the operating state of the high-frequency vacuum resonator for the low-level control system, and the vacuum pump vacuumizes the inside of the first high-frequency vacuum resonator of the radio frequency quadrupole field linear accelerator IH-RFQ 30 through the vacuum port.

In the embodiment of the present disclosure, the high-frequency vacuum resonant cavity of the radio frequency quadrupole field linear accelerator IH-RFQ 30 is cylindrical, and it adopts an H-mode multi-rod structure. The four rod-shaped accelerating electrodes 324 are arranged in sequence along the direction of beam advance. Divided into Radial Matching Section (RMS), Micro Beaming Section, Beaming Section and Acceleration Section. After the continuous beam drawn by the ion source 10 is injected into the radio frequency quadrupole field linear accelerator IH-RFQ 30, it first passes through the radial matching section, so that the phase space distribution of the continuous beam in the horizontal and vertical directions is associated with high-frequency oscillation to meet the requirements of the accelerator. Inject phase space requirements. The micro-bunching section processes the continuous beam passing through the radial matching section, so that the continuous beam forms a pulsed beam with longitudinal intervals. The beamforming section is used to compress the length of the pulse beam formed by the micro beamforming section to form a short pulse cluster. The acceleration section is used to accelerate the short pulse bunch, so that the particle beam is accelerated to the energy section that the first drift tube linear accelerator APF-DTL 50 can receive.

The first medium-energy beam transport line 40 is arranged at the output end of the radio frequency quadrupole field linear accelerator IH-RFQ30, including: multiple quadrupole magnets. Multiple quadrupole magnets are sequentially arranged between the radio frequency quadrupole field linear accelerator IH-RFQ 30 and the first drift tube linear accelerator APF-DTL 50, and the lateral distribution of the radio frequency quadrupole field linear accelerator IH-RFQ 30 is asymmetrically distributed. The beams are converged into a laterally symmetrical and focused particle beam, which helps the lateral matching of the particle beam in the first drift tube linear accelerator APF-DTL 50, thereby reducing the lateral focusing of the first drift tube linear accelerator APF-DTL50. pressure.

The first drift tube linear accelerator APF-DTL 50, which is connected to the outlet of the first medium-energy beam delivery line 40, is used for the second pre-acceleration of the particle beam output by the first medium-energy beam delivery line 40 , so that the particle beam output by the first medium-energy beam transport line 40 is accelerated to the second preset energy. In the embodiment of the present disclosure, if the particle beam is a proton, the second preset energy can be: 3-7 MeV; if the particle beam is ¹² C ⁴⁺ particles, the second preset energy can be 400KeV/u～ 4MeV/u.

According to an embodiment of the present disclosure, as shown in FIG. 7 , the first drift tube linear accelerator APF-DTL 50 includes a second high-frequency vacuum resonant cavity, and the second high-frequency vacuum resonant cavity specifically includes: a fourth cavity 510 , a first Five chambers 520 and a sixth chamber 530 . Wherein, the fifth cavity 520 is disposed between the fourth cavity 510 and the sixth cavity 530 , and forms a sealing structure with the fourth cavity 510 and the sixth cavity 530 .

Specifically, the fourth cavity 510 includes: a second left cavity cover 511 , two adjustable tuners 512 and a fixed tuner 513 . Wherein, two adjustable tuners 512 and a fixed tuner 513 are respectively arranged on the outer surface of the second left chamber cover 511, and the two adjustable tuners 512 are used for real-time adjustment of the first drift tube linear accelerator APF-DTL 50. The cavity frequency, field distribution, etc. are adjusted, and the fixed tuner 513 is used for fixed tuning of the cavity frequency in the first drift tube linear accelerator APF-DTL 50 .

Specifically, as shown in FIGS. 8 and 9 , the fifth chamber 520 includes: an outer shell 521 , a third ridge structure 522 , a fourth ridge structure 523 , a plurality of drift tubes 524 and a plurality of drift tube support seats 525 . Wherein, the third ridge structure 522 and the fourth ridge structure 523 are disposed opposite to the inner surface of the outer shell 521, and a plurality of drift tubes 524 are arranged between the third ridge structure 522 and the fourth ridge structure 523 through a plurality of drift tube support seats 525 . Preferably, half of the drift tubes in the plurality of drift tubes 524 are connected to the third ridge structure 522 , and the other half of the drift tubes are connected to the fourth ridge structure 523 . In the embodiment of the present disclosure, a plurality of drift tubes 524 are alternately connected to the third ridge structure 522 and the fourth ridge structure 523 through the drift tube support seat 525, so that the interior of the second high-frequency vacuum resonator moves forward along the incident particle beam. The orientation is divided into a number of alternating longitudinal and transverse focusing segments. Preferably, a plurality of drift tubes 524 are arranged inside the cavity of the second high-frequency vacuum cavity along the central axis of the second high-frequency vacuum cavity, and the axis of each drift tube 524 is aligned with the central axis of the second high-frequency vacuum cavity. Coincidentally, the beam focusing mode of the drifting pipe section is an alternating phase beamforming mode.

Specifically, as shown in FIG. 7 , the third chamber body 530 includes: a second right chamber cover 531 , a power coupler 532 , a power extractor 533 and a vacuum port. Wherein, the power coupler 532 , the power extractor 533 and the vacuum port are respectively arranged on the outer surface of the second right chamber cover 531 through flanges. The power coupler 532 is used to receive the power of the radio frequency power source, so that the resonant cavity of the first drift tube linear accelerator APF-DTL 50 is in a resonant state. The power extractor 533 is used to provide the operating state of the high-frequency vacuum resonator for the low-level control system, and the vacuum pump vacuumizes the inside of the first high-frequency vacuum resonator of the first drift tube linear accelerator APF-DTL 50 through the vacuum port.

In the embodiment of the present disclosure, the two ridge structures in the first drift tube linear accelerator APF-DTL 50 are arranged symmetrically along the diameter of the cavity cross-section, and are electrically connected to multiple drift tubes 524 through multiple drift tube support seats 525 , a plurality of drift tubes 524, a plurality of drift tube support seats 525 and two ridge structures isolate the second high-frequency vacuum resonant cavity into two halves. Opposite potentials are generated on the two ridge structures and their connected drift tube support 525 , thereby forming an accelerating electric field between the drift tubes 524 . The two ridge structures may be symmetrically arranged in the vertical direction or the horizontal direction of the cavity inner wall of the high frequency vacuum resonant cavity.

The second medium-energy beam transport line 60 is arranged at the output end of the first drift tube linear accelerator APF-DTL 50 and includes: multiple quadrupole magnets. A plurality of quadrupole magnets are sequentially arranged between the first drift tube linear accelerator APF-DTL 50 and the second drift tube linear accelerator APF-DTL 70, and the lateral distribution of the first drift tube linear accelerator APF-DTL 50 is asymmetrical. The beams are converged into a laterally symmetrical and focused beam, which helps the lateral matching of the beams in the second drift tube linear accelerator APF-DTL 70, thereby reducing the stress on the lateral focusing of the second drift tube linear accelerator APF-DTL 70 .

In the embodiment of the present disclosure, the first medium-energy beam delivery line 40 and the second medium-energy beam delivery line 60 include multiple quadrupole magnets, preferably three quadrupole magnets, the number of which can be adjusted according to actual application requirements. Setting, for example, the first medium-energy beam delivery line 40 and the second medium-energy beam delivery line 60 include two, four or more quadrupole magnets to satisfy the lateral matching of the particle beam current, this The disclosed embodiments are not limited to the number of quadrupole magnets.

The second drift tube linear accelerator APF-DTL 70, which is connected to the outlet of the second medium-energy beam delivery line 60, is used to pre-accelerate the particle beam output by the second medium-energy beam delivery line 60 for the third time , so that the particle beam output by the second medium-energy beam transport line 60 is accelerated to a third preset energy. In the embodiment of the present disclosure, if the particle beam is a proton, the third preset energy may be: greater than 7MeV; if the particle beam is ¹² C ⁴⁺ particles, the third preset energy may be 4MeV/u～7MeV /u.

In the embodiment of the present disclosure, the structure of the second drift tube linac APF-DTL 70 is the same as that of the first drift tube linac APF-DTL 50, and its specific structure is shown in Fig. 7, Fig. 8 and Fig. 9, here The structure, connections and functions of the components of the second drift tube linear accelerator APF-DTL 70 will not be described in detail here.

In the embodiment of the present disclosure, the high-frequency vacuum resonant cavities in the radio frequency quadrupole field linear accelerator 30, the first drift tube linear accelerator APF-DTL50 and the second drift tube linear accelerator APF-DTL 70 all adopt a three-layer cavity processing structure , to separate the cavity from the acceleration structure, and ensure the vacuum inside the cavity by means of mechanical connection. The high-frequency vacuum resonant cavity does not need to be welded, which reduces the risk of cavity deformation caused by the welding process and reduces the processing cost. At the same time, when there is a problem with the travel of the acceleration structure, the middle cavity and the acceleration structure can be easily replaced.

In addition, since the beam focusing method of the first drift tube linear accelerator APF-DTL 50 and the second drift tube linear accelerator APF-DTL70 adopts the alternating phase focusing method, when it is necessary to accelerate the charged particle beam to a higher design energy, a drift tube The cavity of the linear accelerator APF-DTL is too long, and the interactive focusing method cannot satisfy the beam focusing, which will lead to an excessive increase in beam emittance and a decrease in beam transmission efficiency. The drift tube linear accelerator APF-DTL adopts the alternating phase method, that is, the positive phase gap, the beam is focused in the radial direction and defocused in the longitudinal direction. With a negative phase gap, the beam is defocused in the radial direction and focused in the transverse direction. Due to the weak lateral focusing force, the lateral defocus of the beam after passing through multiple gaps accumulates too much, resulting in low beam transmission efficiency and serious degradation of beam quality. The first drift tube linac APF-DTL 50 and the second drift tube linac 70 provided by the embodiments of the present disclosure use a two-stage drift tube linac APF-DTL resonant cavity to accelerate the charged particle beam to the designed energy. By placing the beam transport line along the forward direction of the charged particle beam between the two drift tube linear accelerator APF-DTL resonators, the lateral defocus accumulated in the first drift tube linear accelerator APF-DTL 50 is compensated, improving the The beam quality at the entrance of the second drift tube linear accelerator APF-DTL 70 improves the efficiency and beam quality of the overall linear accelerator. At the same time, the design of the two-stage drift tube linear accelerator based on the first drift tube linear accelerator APF-DTL 50 and the second drift tube linear accelerator APF-DTL70 effectively reduces the acceleration energy of each part of the linear accelerator, reduces the design difficulty and cavity processing difficulty.

The high-energy beam transport line 80 is arranged at the output end of the second drift tube linear accelerator APF-DTL 70, and is used to perform phase space matching processing on the particle beam output by the second drift tube linear accelerator APF-DTL 70, to obtain The particle beam processed by phase space matching is output to the beam distribution device.

Specifically, the high-energy beam transport line 80 utilizes quadrupole magnets arranged alternately in magnetic polarity to confine the beam current in the vacuum tube in the horizontal and vertical directions, and conducts phase-by-phase comparison of the charged particle beam drawn by the second drift tube linear accelerator APF-DTL 70. Spatial matching processing, using the dipole magnets distributed between the quadrupole magnets to guide the beam current to the beam distribution device of the injection port of the synchrotron.

According to an embodiment of the present disclosure, as shown in FIG. 1 , the medical ion linear accelerator 100 further includes: a first integrated beam diagnostic element 910 , a second integrated beam diagnostic element 920 and a third integrated beam diagnostic element 930 . Among them, the first integrated beam diagnosis element 910 is arranged on the low-energy beam transmission line 20, and is used to monitor the beam current intensity and phase space parameters on the low-energy beam transmission line 20, and obtain the radio frequency quadrupole field straight line The beam parameters at the entrance of the accelerator 30 further guide the adjustment of the magnet parameters on the low-energy beam delivery line 20 . The second integrated beam diagnostic component 920 is arranged on the first medium-energy beam delivery line 40, and is used to monitor the beam current intensity and phase space parameters on the first medium-energy beam delivery line 40, and obtain the first A beam current parameter at the entrance of the drift tube linear accelerator APF-DTL 50 , and then guide the adjustment of the magnet parameter on the first energy beam transport line 40 . The third integrated beam diagnostic component 930 is arranged on the second medium-energy beam delivery line 60, and is used to monitor the beam current intensity and phase space parameters on the second medium-energy beam delivery line 60, and obtain the first The beam parameters at the entrance of the second drift tube linac APF-DTL 70 guide the adjustment of the magnet parameters on the second energy beam transport line 60 . It should be noted that in the embodiments of the present disclosure, the magnet parameters specifically refer to the magnitude of the magnetic field gradient, etc., and the first integrated beam diagnostic element 910, the second integrated beam diagnostic element 920, and the third integrated beam diagnostic element 930 can be the same integrated beam diagnostic element. diagnostic components.

According to an embodiment of the present disclosure, the medical ion linear accelerator 100 further includes: a power source and a distributed RF power distribution system. The first output end of the power source and the distributed RF power distribution system is connected to an input end of the first drift tube linear accelerator APF-DTL50, and the second output end is connected to an input end of the second drift tube linear accelerator APF-DTL 70 , for adjusting the power of the high-frequency vacuum resonant cavities of the first drift tube linear accelerator APF-DTL 50 and the second drift tube linear accelerator APF-DTL 70 .

In the embodiment of the present disclosure, the first drift tube linac APF-DTL 50 and the second drift tube linac APF-DTL 70 share one power source and distributed RF power distribution system, which can be based on the actual operation process of the drift tube The linear accelerator resonant cavity requires power, and then the adjustable power divider is used to adjust the resonant cavity power input into the drift tube linear accelerator, which reduces the number of power sources and saves costs.

It should be noted that the medical ion linear accelerator 100 provided by the present disclosure is a sealed structure, such as the radio frequency quadrupole field linear accelerator 30, the first drift tube linear accelerator APF-DTL 50 and the second drift tube linear accelerator APF-DTL 70. The cavity and the flange, the cavity and the coupler are sealed with copper gaskets, and the cavity is sealed with an O-ring to ensure the vacuum environment in the cavity.

To sum up, compared with the prior art, the present disclosure at least has the following beneficial effects:

(1) The radio frequency quadrupole field linear accelerator RFQ adopts the radio frequency quadrupole field linear accelerator IH-RFQ, and the cylindrical high-frequency vacuum resonant cavity belongs to the H-mode four-rod structure, that is, four rods are arranged in the cylindrical high-frequency resonant cavity type accelerating electrodes, a pair of ridge structures are arranged vertically and symmetrically in the cylindrical high-frequency vacuum resonator, the first ridge structure on the upper part is connected to two of the four rod-type accelerating electrodes, and the second ridge structure on the lower part The structure is connected to two of the four accelerating electrodes. The high-frequency vacuum resonant cavity of the radio frequency quadrupole field linear accelerator IH-RFQ adopts a left, middle and right three-layer cavity processing structure, which separates the cavity from the accelerating structure and ensures the vacuum through mechanical connection. The high-frequency vacuum resonant cavity does not require welding, which reduces the risk of cavity deformation caused by the welding process and reduces processing costs. At the same time, when the acceleration structure in the radio frequency quadrupole field linear accelerator IH-RFQ fails, the middle cavity and the acceleration structure can be easily replaced.

(2) By using the drift tube linear accelerator APF-DTL as the drift tube linear accelerator, its high-frequency vacuum resonator is divided into several alternating longitudinal focusing sections and transverse focusing sections along the advancing direction of the incident particle beam, and the high-frequency vacuum resonating cavity A pair of ridge structures and a plurality of drift tubes are vertically and symmetrically arranged on the inner wall of the cavity along the diameter of the cavity cross section. The drift tubes are arranged inside the cavity of the high-frequency vacuum cavity along the central axis of the high-frequency vacuum cavity, and alternately The ground is fixed to different ridge structures through support rods, the axis of each drift tube coincides with the central axis of the high-frequency vacuum resonator, and the beam focusing mode of the drift tube section is an alternating phase beamforming mode. Drift tube linear accelerator APF-DTL high-frequency vacuum resonator adopts left, middle and right three-layer cavity processing structure. The cavity and the acceleration structure are separated, and the vacuum is ensured by means of mechanical connection. The high-frequency vacuum resonant cavity does not require welding, which reduces the risk of cavity deformation caused by the welding process and reduces processing costs. At the same time, when there is a problem with the acceleration structure in the drift tube linear accelerator, the middle chamber and the acceleration structure can be easily replaced.

(3) Use two-stage drift tube linear accelerator APF-DTL resonant cavity to accelerate the charged particle beam to the design energy. By placing the beam transport line between the two drift tube linac APF-DTL resonators along the forward direction of the charged particle beam, the lateral defocus accumulated in the first drift tube linac APF-DTL is compensated, and the first drift tube linear accelerator APF-DTL is improved. The beam quality at the entrance of the two-drift tube linear accelerator APF-DTL improves the efficiency of the overall linear accelerator and the beam quality by about 10%. At the same time, the design of the two-stage drift tube linear accelerator APF-DTL effectively reduces the acceleration energy of each part of the linear accelerator, and reduces the difficulty of design and cavity processing.

(4), the first drift tube linac 50 and the second drift tube linac 70 share a power source and a distributed RF power distribution system, which can be based on the power requirements of the drift tube linac resonator during actual operation, Furthermore, the resonant cavity power input into the drift tube linear accelerator is adjusted through the adjustable power divider, which reduces the number of power sources and saves the cost.

While the disclosure has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive.

Those skilled in the art can understand that the features described in various embodiments and/or claims of the present disclosure can be combined and/or combined in various ranges, even if such a combination or combination is not explicitly stated in the present disclosure. In particular, without departing from the spirit and teaching of the present disclosure, the various embodiments of the present disclosure and/or the features described in the claims can be combined and/or combined in various ways. All such combinations and/or combinations fall within the scope of the present disclosure.

While the present disclosure has been shown and described with reference to certain exemplary embodiments thereto, it should be understood by those skilled in the art that other modifications may be made without departing from the spirit and scope of the present disclosure as defined by the appended claims and their equivalents. Various changes in form and details have been made to this disclosure. Therefore, the scope of the present disclosure should not be limited to the above-described embodiments, but should be determined not only by the appended claims, but also by the equivalents of the appended claims.

Claims (10)

1. A medical ion linear accelerator, characterized in that it comprises: The ion source, low-energy beam delivery line, RF quadrupole field linear accelerator, the first medium-energy beam delivery line, the first drift tube linear accelerator, the second medium-energy beam delivery line, and the second drift tube are connected in sequence tube linear accelerator and high-energy beam transport line; among them, The radio frequency quadrupole field linear accelerator includes: a first high frequency vacuum resonator; wherein, the first high frequency vacuum resonator adopts an H-mode multi-rod structure, including a first cavity, a second cavity and a third cavity. A cavity; wherein, the second cavity is disposed between the first cavity and the third cavity, and forms a sealing structure with the first cavity and the third cavity, and the The second cavity includes: two ridge structures and four rod-shaped accelerating electrodes oppositely arranged; two rod-shaped accelerating electrodes in the four rod-shaped accelerating electrodes are connected with the first ridge structure, and the other two rod-shaped accelerating electrodes The electrodes are connected to the second ridge structure. 2. The medical ion linear accelerator according to claim 1, characterized in that, the rod-shaped accelerating electrodes in the four rod-shaped accelerating electrodes are arranged in pairs, wherein the two rod-shaped accelerating electrodes distributed in the vertical direction It is connected with the first ridge structure, and two rod-shaped accelerating electrodes distributed in the horizontal direction are connected with the second ridge structure. 3. The medical ion linear accelerator according to claim 1, characterized in that, the first drift tube linear accelerator and the second drift tube linear accelerator all comprise: a second high-frequency vacuum resonant cavity; wherein, the The second high-frequency vacuum resonant cavity includes: a fourth cavity, a fifth cavity, and a sixth cavity, wherein the fifth cavity is arranged between the fourth cavity and the sixth cavity, And form a sealing structure with the fourth cavity and the sixth cavity, the fifth cavity includes: two opposite ridge structures and a plurality of drift tubes, half of the plurality of drift tubes drift The tube is connected to the third ridge structure, and the other half of the drift tube is connected to the fourth ridge structure. 4. The medical ion linear accelerator according to claim 3, wherein the plurality of drift tubes are alternately connected to the third ridge structure and the fourth ridge structure through the drift tube support base, so that all The interior of the second high-frequency vacuum resonant cavity is divided into a plurality of alternating longitudinal focusing sections and transverse focusing sections along the advancing direction of the incident particle beam. 5. The medical ion linear accelerator according to claim 3, wherein the fourth chamber comprises: a second left chamber cover, two adjustable tuners and a fixed tuner, the two adjustable tuners The tuner and the fixed tuner are respectively arranged on the outer surface of the left cavity cover; the sixth cavity includes: a second right cavity cover, a power coupler, a power extractor and a vacuum port, the power coupler, The power extractor and the vacuum port are respectively arranged on the outer surface of the right chamber cover. 6. The medical ion linear accelerator according to claim 2, wherein the first chamber comprises: a first left chamber cover, two adjustable tuners and a fixed tuner; the two adjustable tuners The tuner and the fixed tuner are respectively arranged on the outer surface of the first left cavity cover; the third cavity includes: the first right cavity cover, a power coupler, a power extractor and a vacuum port, and the power coupler The device, the power extractor and the vacuum port are respectively arranged on the outer surface of the first right chamber cover. 7. The medical ion linear accelerator according to claim 1, wherein the medical ion linear accelerator further comprises: Power source and distributed RF power distribution system, the first output end of which is connected to an input end of the first drift tube linear accelerator, and the second output end is connected to an input end of the second drift tube linear accelerator, for The purpose is to adjust the power of the high-frequency vacuum resonant cavity of the first drift tube linear accelerator and the second drift tube linear accelerator. 8. The medical ion linear accelerator according to claim 1, wherein the medical ion linear accelerator further comprises: The first integrated beam diagnostic component is used to monitor the state of the particle beam output by the low-energy beam transport line; The second integrated beam diagnostic component is used to monitor the state of the particle beam output by the first medium-energy beam transport line; The third integrated beam diagnosis element is used to monitor the state of the particle beam output by the second energy beam transport line. 9. The medical ion linear accelerator according to claim 1, characterized in that, the first medium-energy beam transport line and the second medium-energy beam transport line both comprise: a plurality of quadrupole magnets, The plurality of quadrupole magnets converge the particle beams on the beam transport line into a laterally symmetrical and focused particle beam. 10. The medical ion linear accelerator according to claim 1, wherein the radio frequency quadrupole field linear accelerator accelerates the particle beam outputted by the low-energy beam transport line to a first preset energy, and the The first drift tube linac accelerates the particle beam output through the first medium-energy beam delivery line to the second preset energy, and the second drift tube linac will output the particle beam through the second medium-energy beam delivery line The particle beam is accelerated to a third preset energy; wherein, the first preset energy, the second preset energy and the third preset energy are different in magnitude.

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