CN115798860A - Arc superconducting magnet system for proton acceleration - Google Patents

Abstract

The invention relates to an arc superconducting magnet system for accelerating protons, which comprises an arc superconducting magnet, an ultralow temperature system and a magnet suspension system, wherein the arc superconducting magnet comprises a dipolar magnet, two quadrupolar magnets and a magnet fastening structure; the ultralow temperature system comprises a vacuum container, a cold shield structure, a liquid helium container, an air return pipe, a refrigerating unit and a cold guide structure; the magnet suspension system comprises a liquid helium container pull rod assembly and a cold shield structure pull rod assembly; the arc superconducting magnet provides a magnetic field required by proton acceleration, the ultralow temperature system is used for providing a stable ultralow temperature environment for the superconducting magnet, the magnet suspension system keeps the arc superconducting magnet at a stable spatial physical position, and the arc superconducting magnet, the ultralow temperature system and the magnet suspension system are combined to form a complete arc superconducting magnet system suitable for proton acceleration.

Description

Arc superconducting magnet system for proton acceleration

Technical Field

The invention belongs to the field of superconducting electricians, and particularly relates to an arc superconducting magnet system for proton acceleration, which is used for acceleration of protons in a laser proton radiotherapy system.

Background

As the most ideal radiation therapy radiation of the 21 st century, the use of ion beams in the field of tumor therapy has become increasingly common. The protons and the heavy ions are charged particles, and different from conventional rays such as X rays, y rays and electron beams, after the protons and the heavy ions with certain energy are incident to human tissues, the energy can be gathered on tumors at different depths and different positions by adopting a Bragg Peak broadening technology (SOBP), and meanwhile, the damage to the normal tissues is reduced to the maximum extent. Although proton beam technology is well applied in tumor therapy, due to advanced technology and complex equipment, only a few countries in the world currently master the technology, and a plurality of technical defects still need to be overcome. For example, the treatment terminal technology is complicated, the equipment is huge, especially the weight of the rotating frame for supporting beam multi-directional irradiation reaches hundreds of tons, the huge weight also needs high-precision rotation control requirements, and the difficulty of mechanical structure design is greatly increased. Meanwhile, one future research direction is to integrate proton therapy and heavy ion therapy in the same system to achieve the purpose of reducing the cost of composite therapy. Therefore, miniaturization and weight reduction of the apparatus are the development direction of the radiotherapy apparatus of the new generation. The superconducting magnet has the characteristics of small volume and capability of generating a higher magnetic field under a liquid helium temperature region, and the accelerated deflection radius of particles can be reduced, so that the size of the rack is effectively reduced. It is therefore necessary to apply superconducting magnet technology to proton radiation therapy systems.

Chinese patent CN202210316405.0 discloses a proton accelerator treatment system, in which a secondary magnet B capable of sliding up and down is arranged in a beam guidance system, so that the beam can better meet the treatment requirements, but the magnet is used; chinese utility model patent CN201820142807.2 discloses an accelerator magnet with ultra-strong ability to capture particles, which greatly improves the capture control ability of particles, makes the charged particles controllable to the maximum extent, controls the particles through continuous beam current and focusing, and finally generates higher energy X-rays with ultra-strong penetrating power without using superconducting coils; chinese invention patent CN202010843043.1 discloses a superconducting coil skeleton structure of a superconducting proton cyclotron, which comprises a coil plate and a liquid helium trough plate; the liquid helium trough plate is provided with a channel for communicating the two containing grooves, so that the channel can be provided for the flow of liquid helium in the cooling process, and the framework structure is in a non-arc-shaped spiral tube shape.

Disclosure of Invention

In order to realize the miniaturization and light weight of equipment of a proton radiotherapy system, the invention provides an arc superconducting magnet system for proton acceleration, a high-intensity magnetic field required by particle acceleration is generated by an arc superconducting magnet, the stable high-field operation of the magnet in an ultralow temperature environment for a long time is ensured by adopting a liquid helium soaking-refrigerating machine refrigeration mode, and the corresponding structural characteristics of the magnet are disclosed.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

an arc superconducting magnet system for proton acceleration comprises an arc superconducting magnet, an ultralow temperature system and a magnet suspension system;

the arc superconducting magnet comprises a dipolar magnet, a quadrupolar magnet and a magnet fastening structure; the two-pole magnet and the four-pole magnet are both in a bent oblique solenoid shape, have the same bent central axis and are aligned at two ends, and the magnet fastening structure fixes the relative positions of the two-pole magnet and the four-pole magnet;

the ultralow temperature system is formed by sleeving a liquid helium container, a cold shield structure and a vacuum container from inside to outside, and 3 refrigerators and cold guide structures are adopted for refrigeration and cold guide, the arc-shaped superconducting magnet is relatively fixed inside the liquid helium container, the cold shield structure and the vacuum container are respectively provided with a curved arc tube, and the curved central axis of the curved arc tube is superposed with the curved central axis of the arc-shaped superconducting magnet;

the magnet suspension system comprises a pull rod assembly A and a pull rod assembly B, the pull rod assembly A stabilizes the liquid helium container and the arc-shaped superconducting magnet in position in a vacuum container, and the pull rod assembly B stabilizes the cold shield structure in position in the vacuum container.

Furthermore, the magnet fastening structure comprises a left end face positioning plate, a right end face positioning plate, a middle transition ring, a left pull rod group and a right pull rod group, wherein the left end face positioning plate and the right end face positioning plate are respectively provided with an annular groove and a circumferential limiting block, one end of each of the two-pole magnet and the four-pole magnet is embedded into the annular groove in the left end face positioning plate, the other end of each of the two-pole magnet and the four-pole magnet is embedded into the annular groove in the right end face positioning plate, the circumferential limiting blocks limit the circumferential positions of the two-pole magnet and the four-pole magnet, and the arc superconducting magnet is integrally tensioned through the transition ring, the left pull rod group and the right pull rod group.

Furthermore, the left pull rod group and the right pull rod group are telescopic rod assemblies with positive and negative threads, the transition ring is located in the middle section of the arc superconducting magnet, one end of the left pull rod group is connected with the left end face positioning plate through a hinge, the other end of the left pull rod group is connected with the transition ring through a hinge, one end of the right pull rod group is connected with the transition ring through a hinge, the other end of the right pull rod group is connected with the right end face positioning plate through a hinge, and the left end face positioning plate and the right end face positioning plate are fastened relatively by adjusting the lengths of the left pull rod group and the right pull rod group.

Furthermore, the vacuum container consists of a vacuum container shell and a room temperature bent pipe, the whole vacuum container is of a sealing structure, the internal environment is a vacuum environment, and the external environment is a room temperature environment; the cold shield structure consists of a cold shield shell and a low-temperature bent pipe; the liquid helium container is a sealed structure consisting of a liquid helium shell and an ultralow temperature bent pipe, and the arc superconducting magnet is arranged inside the liquid helium container; the bending radii of the room-temperature bent pipe, the low-temperature bent pipe and the ultralow-temperature bent pipe are the same as those of the arc-shaped superconducting magnet, and the bending central axes of the room-temperature bent pipe, the low-temperature bent pipe and the ultralow-temperature bent pipe coincide after the room-temperature bent pipe, the low-temperature bent pipe and the ultralow-temperature bent pipe are integrally assembled; the vacuum container, the cold shield structure and the liquid helium container are separated by a certain distance.

The refrigerating unit comprises 1 primary refrigerator, a secondary refrigerator a and a secondary refrigerator b, the primary refrigerator transmits the prepared cold quantity to the cold screen structure through the cold guide assembly a, the secondary refrigerator a performs segmented refrigeration on a current lead through connection with a current lead joint in the arc superconducting magnet, the secondary refrigerator b transmits the cold quantity for the cold screen structure and the liquid helium container through the cold guide assembly b and the condenser assembly respectively, the cold guide assembly a, the cold guide assembly b and the condenser assembly are all made of superconducting magnets with high thermal conductivity at low temperature, and the cold quantities generated by the primary refrigerator, the secondary refrigerator a and the secondary refrigerator b are transmitted to the arc superconducting magnet to maintain the required ultralow temperature environment.

Furthermore, a gas return pipe is welded on the shell of the vacuum container, a liquid conveying pipeline and a gas inlet and outlet valve port are formed in the gas return pipe and used for conveying liquid helium and gas in the liquid helium container, and the low-temperature section of the gas return pipe is connected with the cold shield structure through a cold guide assembly c.

Furthermore, the pull rod assembly A and the pull rod assembly B are both elongated rod assemblies with adjustable lengths, one end of the pull rod assembly A is connected with the liquid helium container through a rotating support, the other end of the pull rod assembly A is connected with the vacuum container through a rotating support, one end of the pull rod assembly B is connected with the cold shield structure through a rotating support, the other end of the pull rod assembly B is connected with the vacuum container through a rotating support, and the liquid helium container and the cold shield structure are hung inside the vacuum container through the pull rod assembly A and the pull rod assembly B.

Has the advantages that:

according to the arc superconducting magnet system for proton acceleration, a magnetic field environment required by proton acceleration is generated by an arc superconducting magnet, a stable ultralow temperature environment is formed by adopting a liquid helium soaking and refrigerating and cold conducting mode of a refrigerator, the required ultralow temperature is provided for normal operation of the superconducting magnet, the arc superconducting magnet is relatively stabilized in the vacuum container by the suspension system of the magnet, the superconducting magnet can generate a magnetic field higher than that of a conventional magnet in a liquid helium temperature region, the internal structure of the whole device system is simple, the whole device system is small in size, light in weight and low in maintenance cost, and the target requirements of miniaturization and light weight of equipment of a proton radiotherapy system can be met.

Drawings

FIG. 1 is a schematic diagram of the overall configuration of an arcuate superconducting magnet system for proton acceleration according to the present invention;

FIG. 2 is a schematic illustration of the installation location of the arcuate superconducting magnet system for proton acceleration of the present invention;

FIG. 3 is a schematic view of the installation of the arc-shaped superconducting magnet of the present invention;

fig. 4 is an overall outline view of the present invention.

Description of reference numerals: the device comprises a vacuum container 1, a vacuum container shell 1-1, a room temperature bent pipe 1-2, a cold shield structure 2-1, a cold shield shell 2-2, a low temperature bent pipe 2-2, a liquid helium container 3-1, a liquid helium shell 3-2, an ultralow temperature bent pipe 3-2, an arc superconducting magnet 4-1, a dipolar magnet 4-2, a quadrupole magnet 4-3, a left end positioning plate 4-4, a left pull rod set 4-5, a transition circular ring 4-6, a right pull rod set 4-7, a right end positioning plate 5, a primary refrigerator 5-1, a cold guide component a 5-6, a secondary refrigerator a 7, a gas return pipe 7-1, a cold guide component c 7-8, a secondary refrigerator B8-1, a cold guide component B8-2, a condenser component 9, a pull rod component A and a pull rod component B10.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments, and all other embodiments obtained by a person skilled in the art based on the embodiments of the present invention belong to the protection scope of the present invention without creative efforts.

As shown in fig. 1, 2, and 4, the arc superconducting magnet system for proton acceleration of the present invention includes an arc superconducting magnet 4, an ultra-low temperature system, and a magnet suspension system. The arc superconducting magnet 4 comprises a two-pole magnet 4-1, a four-pole magnet 4-2 and a magnet fastening structure for fixing the relative positions of the two magnets. The arc superconducting magnet 4 is electrified and excited to provide a required magnetic field environment for proton acceleration; the ultralow temperature system comprises a vacuum container 1, a cold shield structure 2, a liquid helium container 3, an arc superconducting magnet 4, an air return pipe 7, a refrigerating unit and a cold guide structure, and provides a stable ultralow temperature environment for the normal operation of the arc superconducting magnet 4 in a liquid helium soaking-refrigerating machine refrigerating mode; the magnet suspension system comprises an arc superconducting magnet 4, a pull rod assembly A9 of a liquid helium container 3 and a pull rod assembly B10 of a cold shield structure 2, the arc superconducting magnet 4, the liquid helium container 3 and the cold shield structure 2 are suspended in a vacuum container 1, and the three parts are combined to form a complete arc superconducting magnet system for accelerating protons.

The vacuum container 1 consists of a vacuum container shell 1-1 and a room temperature bent pipe 1-2, and the whole body is of a sealing structure. The outside of the vacuum container 1 is a room temperature environment, the inside of the vacuum container is a vacuum environment, the cold shield structure 2 consists of a cold shield shell 2-1 and a low-temperature bent pipe 2-2 and is positioned inside the vacuum container, the liquid helium container 3 consists of a liquid helium shell 3-1 and an ultralow-temperature bent pipe 3-2 to form a sealing structure and is surrounded by the cold shield structure 2, a certain amount of liquid helium is contained in the liquid helium container 3, the arc-shaped superconducting magnet 4 is placed inside the liquid helium container 3, particularly, the room temperature bent pipe 1-2, the low-temperature bent pipe 2-2 and the ultralow-temperature bent pipe 3-2 are the same as the bending radiuses of a dipolar magnet 4-1 and a quadrupole magnet 4-2 in the arc-shaped superconducting magnet 4, and the bending central axes of all the bent pipes coincide after the whole assembly; the vacuum container 1, the cold shield structure 2 and the liquid helium container 3 are separated by a certain distance.

As shown in fig. 2 and 3, in the arc-shaped superconducting magnet 4 of the present invention, the two-pole magnet 4-1 and the four-pole magnet 4-2 are each in the shape of a curved helical coil and have the same curved central axis. The magnet fastening structure sequentially comprises a left end face positioning plate 4-3, a left pull rod group 4-4, a transition ring 4-5, a right pull rod group 4-6 and a right end face positioning plate 4-7, wherein the left pull rod group 4-4 and the right pull rod group 4-6 are slender rod pieces with adjustable lengths; the left end face positioning plate 4-3 and the right end face positioning plate 4-7 are respectively provided with an annular groove and a circumferential limiting block, one end of each of the dipolar magnet 4-1 and the quadrupole magnet 4-2 is embedded into the annular groove on the left end face positioning plate 4-3, the other end of each of the dipolar magnet 4-1 and the quadrupole magnet 4-2 is embedded into the annular groove on the right end face positioning plate 4-7, the transition ring 4-5 is positioned in the middle section of the arc-shaped superconducting magnet 4, one end of each of the left pull rod group 4-4 is connected with the left end face positioning plate 4-3 through a hinge, the other end of each of the left pull rod group 4-4 is connected with the left side of the transition ring 4-5 through a hinge, one end of each of the right pull rod group 4-6 is connected with the right side of the transition ring 4-5 through a hinge, the other end of each of the right pull rod group is connected with the right end face positioning plate 4-7 through a hinge, and finally the left and right pull rod groups are adjusted in length to relatively tighten the left and right end face positioning plates, so as to realize the relative position fixation between the dipolar magnet 4-1 and the quadrupole magnet 4-2.

As shown in fig. 1, the magnet suspension system includes a pull rod assembly A9 and a pull rod assembly B10, both of the pull rod assemblies a and B are elongated rod assemblies with adjustable lengths, one end of the pull rod assembly A9 is connected to the liquid helium container 3 through a rotating bracket, the other end of the pull rod assembly a is connected to the vacuum container 1 through a rotating bracket, so as to stabilize the position of the arc-shaped superconducting magnet 4 in the vacuum container 1, one end of the pull rod assembly B10 is connected to the cold shield structure 2 through a rotating bracket, and the other end of the pull rod assembly B is connected to the vacuum container 1 through a rotating bracket, so as to stabilize the position of the cold shield structure 2 in the vacuum container 1.

As shown in fig. 1, the arc superconducting magnet system for proton acceleration of the present invention employs 3 refrigerators and a cold conduction structure, wherein 1 of the 3 refrigerators includes a primary refrigerator 5, a secondary refrigerator a6 and a secondary refrigerator b8, the primary refrigerator 5 conducts all refrigeration capacity to the cold shield structure 2 through a cold conduction assembly a5-1, the secondary refrigerator a6 conducts segmented refrigeration to a current lead of the arc superconducting magnet 4 by being connected to an insulated electrical connector in the magnet, the secondary refrigerator b8 conducts refrigeration to the cold shield mechanism 2 and the liquid helium container 3 through a cold conduction assembly b8-1 and a condenser assembly 8-2, respectively, and particularly, the cold conduction assembly a5-1, the cold conduction assembly b8-1 and the condenser assembly 8-2 are made of materials with high thermal conductivity at low temperature, and the refrigeration capacity generated by the 3 refrigerators is conducted to the arc superconducting magnet 4 for maintaining the required ultra-low temperature environment.

As shown in fig. 1 and 2, a gas return pipe 7 is welded on the vacuum container housing 1-1, and a liquid conveying pipeline and an inlet/outlet gas valve port are arranged in the gas return pipe 7, and are used for conveying liquid helium and gas in the liquid helium container 3, and in order to reduce heat leakage of the system generated by the gas return pipe 7, a cold guide assembly c7-1 is arranged at the middle position of the gas return pipe 7, and the gas return pipe 7 is connected with the cold shield structure 2, so as to realize temperature segmentation of the gas return pipe 7.

Claims (7)

1. An arc superconducting magnet system for proton acceleration, characterized by: the superconducting magnet consists of an arc superconducting magnet, an ultralow temperature system and a magnet suspension system;

the arc superconducting magnet comprises a dipolar magnet, a quadrapole magnet and a magnet fastening structure; the two-pole magnet and the four-pole magnet are both in a bent oblique solenoid shape, have the same bent central axis and are aligned at two ends, and the magnet fastening structure fixes the relative positions of the two-pole magnet and the four-pole magnet;

the ultralow temperature system is formed by sleeving a liquid helium container, a cold shield structure and a vacuum container from inside to outside, and 3 refrigerators and cold guide structures are adopted for refrigeration and cold guide, the arc-shaped superconducting magnet is relatively fixed inside the liquid helium container, the cold shield structure and the vacuum container are respectively provided with a curved arc tube, and the curved central axis of the curved arc tube is superposed with the curved central axis of the arc-shaped superconducting magnet;

the magnet suspension system comprises a pull rod assembly A and a pull rod assembly B, the pull rod assembly A stabilizes the liquid helium container and the arc-shaped superconducting magnet in position in a vacuum container, and the pull rod assembly B stabilizes the cold shield structure in position in the vacuum container.

2. The arc superconducting magnet system for proton acceleration according to claim 1, wherein the magnet fastening structure is composed of a left end face positioning plate, a right end face positioning plate, a middle transition ring, a left pull rod set and a right pull rod set, the left end face positioning plate and the right end face positioning plate are respectively provided with an annular slot and a circumferential limiting block, one end of the dipolar magnet and the quadrupole magnet is embedded into the annular slot on the left end face positioning plate, the other end of the dipolar magnet and the quadrupole magnet is embedded into the annular slot on the right end face positioning plate, the circumferential limiting block limits the circumferential positions of the dipolar magnet and the quadrupole magnet, and the arc superconducting magnet is integrally tensioned through the transition ring, the left pull rod set and the right pull rod set.

3. The arc superconducting magnet system for proton acceleration according to claim 2, wherein the left and right pull rod sets are telescopic rod assemblies with positive and negative threads, the transition ring is located in the middle section of the arc superconducting magnet, one end of the left pull rod set is connected with the left end face positioning plate through a hinge, the other end of the left pull rod set is connected with the transition ring through a hinge, one end of the right pull rod set is connected with the transition ring through a hinge, the other end of the right pull rod set is connected with the right end face positioning plate through a hinge, and the left end face positioning plate and the right end face positioning plate are fastened relatively by adjusting the lengths of the left and right pull rod sets.

4. The arc-shaped superconducting magnet system for proton acceleration according to claim 1, wherein the vacuum vessel is composed of a vacuum vessel shell and a room temperature bent pipe, and is integrally a sealed structure, the internal environment is a vacuum environment, and the outside is a room temperature environment; the cold shield structure consists of a cold shield shell and a low-temperature bent pipe; the liquid helium container is a sealed structure consisting of a liquid helium shell and an ultralow temperature bent pipe, and the arc superconducting magnet is arranged inside the liquid helium container; the bending radiuses of the room-temperature bent pipe, the low-temperature bent pipe and the ultralow-temperature bent pipe are the same as those of the arc superconducting magnet, and the bending central axes of the room-temperature bent pipe, the low-temperature bent pipe and the ultralow-temperature bent pipe coincide after the room-temperature bent pipe, the low-temperature bent pipe and the ultralow-temperature bent pipe are integrally assembled; the vacuum container, the cold shield structure and the liquid helium container are separated by a certain distance.

5. The arc superconducting magnet system for proton acceleration according to claim 1, wherein the refrigerating group is composed of 1 primary refrigerator, a secondary refrigerator a and a secondary refrigerator b, the primary refrigerator conducts the produced cold to the cold shield structure through the cold conduction component a, the secondary refrigerator a conducts the segmented refrigeration to the current lead by connecting with the current lead joint in the arc superconducting magnet, the secondary refrigerator b conducts the cold to the cold shield structure and the liquid helium container through the cold conduction component b and the condenser component respectively, the cold conduction component a, the cold conduction component b and the condenser component are all made of materials with high thermal conductivity at low temperature, and the cold produced by the primary refrigerator, the secondary refrigerator a and the secondary refrigerator b is conducted to the arc superconducting magnet for maintaining the required ultra-low temperature environment.

6. The arc superconducting magnet system for proton acceleration according to claim 4, wherein a gas return pipe is welded on the vacuum container shell, a liquid conveying pipe and a gas inlet and outlet valve port are arranged in the gas return pipe and used for conveying liquid helium and gas in the liquid helium container, and the low-temperature section of the gas return pipe is connected with the cold shield structure through a cold guide assembly c.

7. The arc-shaped superconducting magnet system for proton acceleration according to claim 1, wherein the tie rod assemblies A and B are elongated rod assemblies with adjustable lengths, one end of the tie rod assembly A is connected with the liquid helium container through a rotating bracket, the other end of the tie rod assembly A is connected with the vacuum container through a rotating bracket, one end of the tie rod assembly B is connected with the cold shield structure through a rotating bracket, the other end of the tie rod assembly B is connected with the vacuum container through a rotating bracket, and the tie rod assemblies A and B suspend the liquid helium container and the cold shield structure inside the vacuum container.

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