Isochronous cyclotron employing magnetic field concentration or guiding sectors

Abstract

An isochronous cyclotron includes one or more coils and a plurality of pairs of bulk superconductor sectors (950, 955). The one or more coils can be configured to produce a magnetic field in a beam chamber having a magnetic flux density that increases radially from a central axis of the beam chamber and oriented substantially perpendicular to a central acceleration plane of the beam chamber (910). Each pair of bulk superconductor sectors can be disposed on opposite sides of the central acceleration plane. The plurality of pairs of bulk superconductor sectors can be configured to direct or concentrate the magnetic field (960) to provide an axial focusing component of the magnetic field.

Description

Background Technology

[0001] refer to Figure 1 The diagram illustrates an isochronous cyclotron accelerator according to conventional technology. The isochronous cyclotron accelerator 100 includes a beam chamber 105 having a central axis and a central acceleration plane. The isochronous cyclotron accelerator 100 also includes a particle source 115 configured to introduce charged particles into the beam chamber 105 near its central axis.

[0002] One or more coils 125 are arranged around the beam chamber 105. The coils 125 are configured to generate a magnetic field in the beam chamber 105 having a magnetic flux density that increases radially from the central axis of the beam chamber 105 and is oriented perpendicular to the central acceleration plane. One or more radio frequency (RF) drive circuits (not shown) are configured to accelerate charged particles 220 in the beam chamber 105, such as..., in a trajectory 230 extending outward from the central axis. Figure 2 As shown. After acceleration along trajectory 230, charged particles 220 can be output from isochronous cyclotrons 100, 200 through one or more ports 235.

[0003] In isochronous cyclotrons 100 and 200, the magnetic field increases with the radius of the beam chamber 105 to maintain a constant angular frequency of the particles. As the radius increases, the particle frequency becomes independent of the particle's energy. However, this leads to axial (e.g., vertical) instabilities in the axially symmetric magnetic field. These axial instabilities cause vertical defocusing oscillations in the particle beam.

[0004] To compensate for axial instability, the magnetic field is modified in the azimuth angle to focus the particle beam. To modify the magnetic field in the azimuth angle, isochronous cyclotrons 100, 200, and 300 include multiple sector peak pairs 140, 240, 340, and 345 and multiple sector valley pairs 150, 250, 350, and 355, positioned on opposite sides of the central acceleration plane 310, such as... Figure 3 As shown in the figure. Sector peaks 140, 240, 340, 345 and sector valleys 150, 250, 350, 355 can be made of iron or other ferromagnetic materials. Figure 3A cross-sectional view of the radial arc along beam chamber 105 is shown. A magnetic field 360 generated by one or more coils 125 perpendicular to the central acceleration plane 310 is also shown. The magnetic flux density is higher between sector peak pairs 140, 240, 340, and 345 because the sector peaks 140, 240, 340, and 345 are closer together, while the magnetic flux density is lower between sector valley pairs 150, 250, 350, and 355. The resulting local compaction and decompaction of the magnetic flux density can provide an axial focusing component along the particle path. Furthermore, charged particles can experience axial restoring forces at the edges of the sectors. The axial restoring forces act toward the central acceleration plane 310. Dots represent particles with a velocity component entering the page, while crosses represent particles with a velocity component toward the page. The inconsistency in the magnetic field (which is close to the boundary between sector peaks 140, 240, 340, 345 and sector valleys 150, 250, 350, 355 and provides axial restoring force) is generally referred to as a flutter field. In some cases, sector valleys 150, 250, 350, 355 may also be referred to as flutter sectors, flutter plates, etc.

[0005] Now for reference Figure 4 Sector peaks and valleys 440 can have wedge-shaped shape factors. Alternatively, sector peaks and valleys 540 can have spiral-shaped shape factors, such as... Figure 5 As shown. The spiral shape of the sector peaks and valleys 540 provides additional axial focusing.

[0006] A larger average magnetic field 360, providing a tighter helical deflection of charged particles 220, allows for a reduction in the size of the isochronous cyclotrons 100 and 200. However, as the average magnetic field 360 increases, the flutter field decreases relative to the average magnetic field. Therefore, axial instability increases. Furthermore, ferromagnetic sectors saturate when the magnetic field increases beyond the magnetic saturation limit of the sector material. When ferromagnetic sectors saturate, they can no longer generate the flutter field at their boundaries to provide axial focusing.

[0007] To provide additional magnetic flutter flux, the valley sector 640 may also include an electromagnetic coil 645 disposed around the outer edge of the valley sector 640, such as... Figure 6As shown. In one embodiment, the electromagnetic coil 645 arranged around the outer edge of the valley sector 640 can be a superconducting coil. However, a superconducting coil adds complexity due to the need to route current to and from the valley sector, and the need to cool the valley sector below the critical temperature of the superconductor of the coil, etc. Furthermore, isochronous cyclotrons typically include twelve to twenty valley sectors 640. Therefore, the amount of superconducting coil 645 used to wind around the valley sector 640 can lead to a significant increase in the cost of the isochronous cyclotron 100, 200. Additionally, the preferred tips of the valley sector 640 need to be rounded to accommodate the coil 645 arranged around the outer edge of the valley sector 640. Furthermore, the preferred helical shape of the recessed portion of the valley sector 640 increases the complexity of winding the coil 645 around the outer edge of the valley sector.

[0008] Therefore, there is an ongoing need to improve particle acceleration techniques in isochronous cyclotrons to allow for further reductions in the size and / or cost of isochronous cyclotrons. Summary of the Invention

[0009] The present technology can be best understood by referring to the following description and figures, which are used to illustrate embodiments of the present technology for generating flutter fields in isochronous cyclotrons.

[0010] In one embodiment, an isochronous cyclotron accelerator may include a beam chamber, a particle source, multiple pairs of bulk superconducting sectors, one or more coils, and one or more radio frequency (RF) drive circuits. The beam chamber may include a central axis and a central acceleration plane. The particle source may be coupled to the central acceleration plane near the central axis of the beam chamber. One or more coils may be arranged around the beam chamber. One or more RF drive circuits may be configured to accelerate charged particles in an orbital trajectory extending outward from the central axis. Each pair of bulk superconducting sectors may be positioned on opposite sides of the central acceleration plane.

[0011] In another embodiment, the charged particle acceleration method may include providing a beam chamber and a plurality of bulk superconductor sector pairs. Each bulk superconductor sector pair may also be disposed on opposite sides of a central acceleration plane of the beam chamber. Furthermore, the bulk superconductor sector pairs may be spaced apart from each other along a radial arc of the beam chamber. The method also includes providing a magnetic field in the beam chamber having a magnetic flux density that increases radially from the central axis of the beam chamber and being oriented substantially perpendicular to the central acceleration plane. Additionally, the plurality of bulk superconductor sector pairs may be configured to guide or concentrate at least a portion of the magnetic field between the plurality of bulk superconductor sector pairs.

[0012] This overview is provided to introduce, in a simplified form, a series of concepts that will be further described in the detailed description below. This overview is not intended to identify key or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter. Attached Figure Description

[0013] Embodiments of this technology are shown by way of example rather than limitation in the accompanying drawings, in which the same reference numerals denote similar elements, and in the drawings:

[0014] Figure 1 An isochronous cyclotron accelerator based on conventional technology is shown.

[0015] Figure 2 The beam chamber of an isochronous cyclotron accelerator according to conventional technology is shown.

[0016] Figure 3 A cross-sectional view of the radial arc along the beam chamber according to conventional techniques is shown.

[0017] Figure 4 The shape factor of a sector of a beam chamber according to conventional technology is shown.

[0018] Figure 5 Another shape factor of the sector of the beam chamber according to conventional technology is shown.

[0019] Figure 6 The valley sector is shown as an electromagnetic coil wound according to conventional techniques.

[0020] Figure 7A and Figure 7B An isochronous cyclotron accelerator according to various aspects of the present technology is shown.

[0021] Figure 8A and Figure 8B An isochronous cyclotron accelerator according to various aspects of the present technology is shown.

[0022] Figure 9 The beam chamber of an isochronous cyclotron accelerator according to various aspects of the present technology is shown.

[0023] Figure 10 A method for accelerating charged particles according to various aspects of the present technology is shown.

[0024] Figure 11 A method for accelerating charged particles according to various aspects of the present technology is shown.

[0025] Figure 12 An exemplary particle therapy system according to various aspects of the present technology is shown. Detailed Implementation

[0026] Reference will now be made in detail to embodiments of the present technology, examples of which are illustrated in the accompanying drawings. While the present technology will be described in conjunction with these embodiments, it should be understood that they are not intended to limit the present technology to these embodiments. Rather, the invention is intended to cover substitutions, modifications, and equivalents that may be included within the scope of the invention as defined by the appended claims. Furthermore, numerous specific details are set forth in the following detailed description of the present technology to provide a thorough understanding of it. However, it should be understood that the present technology can be practiced without these specific details. In other examples, well-known methods, processes, components, and circuits have not been described in detail so as not to unnecessarily obscure aspects of the present technology.

[0027] The following embodiments of the present technology are presented using routines, modules, logic blocks, and other symbolic representations of operations on data within one or more electronic devices. These descriptions and representations are means by which those skilled in the art most effectively convey the essence of their work to others skilled in the art. Routines, modules, logic blocks, etc., are generally considered herein as self-consistent sequences of processes or instructions that result in desired outcomes. These processes involve the physical manipulation of physical quantities. Typically, although not essential, these physical manipulations take the form of electrical or magnetic signals that can be stored, transmitted, compared, and otherwise manipulated within an electronic device. For convenience, and with reference to general usage, and with reference to embodiments of the present technology, these signals are referred to as data, bits, values, elements, symbols, characters, items, numbers, strings, etc.

[0028] However, it should be remembered that these terms will be interpreted as references to physical operations and quantities, and are merely convenient notations, and will be further interpreted according to terminology commonly used in the art. Unless otherwise stated, as will be apparent from the following discussion, it should be understood that, through the discussion of this art, the use of terms such as "receiving" refers to the actions and processes of electronic devices such as electronic computing devices that operate and convert data. Data is represented as physical (e.g., electronic) quantities within the logic circuits, registers, memories, etc., of electronic devices, and is transformed into other data similarly represented as physical quantities within electronic devices.

[0029] In this application, the use of antonymous conjunctions is intended to include conjunctions. The use of definite or indefinite articles is not intended to indicate cardinality. In particular, references to “the” object or “an” object are intended to also indicate one of a possible plurality of such objects. The use of terms such as “comprising,” “including,” “containing,” “comprises,” etc., specifies the presence of the stated element but does not exclude the presence or addition of one or more other elements or groups thereof. It should also be understood that although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used herein to distinguish one element from another. For example, without departing from the scope of the embodiments, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. It should also be understood that when an element is referred to as “coupled” to another element, it may be directly or indirectly connected to the other element, or there may be intermediate elements. Conversely, when an element is referred to as “directly connected” to another element, there are no intermediate elements. It should also be understood that the term “and / or” includes any and all combinations of one or more related elements. It should also be understood that the wording and terminology used herein are for descriptive purposes and should not be considered restrictive.

[0030] Isochronous cyclotrons can generate continuous, high-current particle beams, which can be used, for example but not limited to, proton therapy systems for rapid patient throughput and modern treatment modalities for cancer, tumors, etc. Various aspects of this technology provide isochronous cyclotrons employing magnetic field concentrating or guiding sectors. These concentrating or guiding sectors can be passive bulk superconducting sectors. The bulk superconducting sectors can be configured to generate a beam-focusing oscillating magnetic field, commonly referred to as a flutter field, along the beam trajectory within the isochronous cyclotron. The oscillating magnetic field, finely tuned by the guiding and / or concentrating bulk superconducting sectors, acts as a magnetic lens to shape and / or guide the main field of the particle beam. The oscillating magnetic field generated by the guiding and / or concentrating bulk superconducting sectors allows for the use of higher magnetic fields within the beam chamber without practical magnetic field limitations. Therefore, the size and cost of the isochronous cyclotron can be reduced.

[0031] See now Figure 7A and Figure 7B The beam chamber of an isochronous cyclotron accelerator according to various aspects of the present technology is shown. Figure 7A A plan view of one side of the beam chamber is shown. Figure 7BA cross-sectional view along the radial arc of the beam chamber is shown. The isochronous cyclotron accelerator 700 may include a beam chamber having a central axis and a central acceleration plane 710. The isochronous cyclotron accelerator 700 may also include a particle source configured to introduce charged particles 720 into the beam chamber near its central axis. In one embodiment, the particle source may be located near the central axis of the beam chamber. In another embodiment, the particle source may inject particles into the beam chamber near its central axis. As used herein, a beam chamber refers to the region where charged particles are accelerated. In one embodiment, the beam chamber may be a region within a vacuum chamber (not shown).

[0032] One or more coils 725 may be arranged around the beam chamber. These coils 725 may be configured to generate a magnetic field in the beam chamber having a magnetic flux density that increases radially from the central axis of the beam chamber and is oriented substantially perpendicular to the central acceleration plane 710. In one embodiment, the one or more coils 725 may include a pair of magnetic coils surrounding the central axis and arranged on opposite sides of the central acceleration plane 710 of the beam chamber. Current flowing through the one or more coils 725 generates a magnetic field perpendicular to the central acceleration plane 710 and having a radially increasing flux density. In one embodiment, the one or more coils 725 may be one or more superconducting coils. In one embodiment, the superconductor of the one or more coils 725 may be a high-temperature superconductor. In another embodiment, the superconductor of the one or more electromagnetic coils 725 may be a medium-temperature superconductor.

[0033] The isochronous cyclotron accelerator 700 may also include a plurality of bulk superconductor sector pairs 750, 755. The plurality of bulk superconductor sector pairs 750, 755 may be disposed inside or outside the beam chamber and / or vacuum chamber. The plurality of bulk superconductor sector pairs 750, 755 may be disposed on opposite sides of the central acceleration plane 710, wherein the plurality of bulk superconductor sector pairs 750, 755 are spaced apart from each other 765 along a radial arc of the beam chamber. In one embodiment, the plurality of bulk superconductor sector pairs 750, 755 may include bulk high-temperature superconductors. In another embodiment, the bulk superconductor sectors 750, 755 may include bulk intermediate-temperature superconductors. Bulk high-temperature superconducting materials may include, but are not limited to, rare-earth barium copper oxides (REBCOs) (such as yttrium barium copper oxide (YBCO)), or gadolinium barium copper oxide (GdBCO), or europium barium copper oxide (EUBCO), lanthanum barium copper oxide (LBCO), and different types of bismuth strontium calcium copper oxides (BSCCOs). Bulk mid-temperature superconducting materials may include, but are not limited to, magnesium diboride (MgB2) or iron (Fe)-based superconductors, also known as phosphorus group compounds. As used herein, the term bulk superconducting material refers to a superconducting material, as opposed to a structure that combines a superconducting material with a resistive conductor (such as copper, silver, etc.), which is also commonly referred to as a superconductor and is typically fabricated in the form of strips, ribbons, or wires. As used herein, high-temperature superconducting materials refer to materials exhibiting superconductivity above about 40 Kelvin (K). As used herein, mid-temperature superconducting materials refer to materials exhibiting superconductivity above about 25 Kelvin (K). In one embodiment, the plurality of bulk superconductor sector pairs 750, 755 may include bulk type II superconductors. In one embodiment, the bulk type II superconductors may be maintained in a mixed state by one or more coolers (not shown), which are thermally coupled to the plurality of bulk superconductor sector pairs 750, 755. The one or more coolers may include one or more electrocoolers, a refrigerant bath, etc.

[0034] Although Figure 7AFour bulk superconductor sector pairs 750, 755 are shown, but the isochronous cyclotron accelerator 700 may include any number of bulk superconductor sector pairs 750, 755. Furthermore, the guidance and / or concentration of magnetic fields through the bulk superconductor sectors 750, 755, and consequently, axial focusing by magnetic flux, can be a combination of the bulk superconductor sector size, shape, density, and other physical properties. For example, in one embodiment, the multiple bulk superconductor sector pairs 750, 755 may have a wedge shape factor. In another embodiment, the multiple bulk superconductor sector pairs 750, 755 may have a helical shape factor. In one embodiment, the multiple bulk superconductor sector pairs 750, 755 may have beveled edges. In one embodiment, the multiple bulk superconductor sector pairs 750, 755 may have raised edges. In one embodiment, the multiple bulk superconductor sector pairs 750, 755 may have a radial width substantially equal to the radial spacing between adjacent bulk superconductor sectors 750, 755. In another embodiment, the plurality of bulk superconductor sector pairs 750, 755 may have a radial width much wider than the radial spacing between adjacent bulk superconductor sectors 750, 755. In yet another embodiment, the plurality of bulk superconductor sector pairs 750, 755 may have a radial width much narrower than the radial spacing between adjacent bulk superconductor sectors 750, 755. In one embodiment, the gap 765 between the plurality of bulk superconductor sector pairs 750, 755 may be filled with a mechanical reinforcement (not shown), such as a metal or ceramic reinforcement, glass fiber reinforced epoxy resin, carbon fiber reinforced polymer, or the like.

[0035] A radio frequency (RF) drive circuit (not shown) can be configured to accelerate charged particles 720 in a beam chamber along an orbital trajectory 730 extending outward from the central axis. In one embodiment, the RF driver can be radially positioned between adjacent bulk superconductor sector pairs 750, 755 (not shown) to accelerate the particles. After acceleration along the orbital trajectory 730, the charged particles 720 can be output from the isochronous cyclotron 700 through one or more ports 735.

[0036] Now for reference Figure 8A and Figure 8B The beam chamber of an isochronous cyclotron accelerator according to various aspects of the present technology is shown. Figure 8A A plan view of one side of the beam chamber is shown. Figure 8BA cross-sectional view along the radial arc of the beam chamber is shown. The isochronous cyclotron accelerator 800 may include a beam chamber having a central axis and a central acceleration plane 810. The isochronous cyclotron accelerator 800 may also include a particle source configured to introduce charged particles 820 into the beam chamber near its central axis. In one embodiment, the particle source may be located near the central axis of the beam chamber. In another embodiment, the particle source may inject particles into the beam chamber near its central axis.

[0037] One or more coils 825 may be arranged around the beam chamber. These coils 825 may be configured to generate a magnetic field in the beam chamber having a magnetic flux density that increases radially from the central axis of the beam chamber and is oriented substantially perpendicular to the central acceleration plane 810. In one embodiment, the one or more coils 825 may include a pair of coils surrounding the central axis and arranged on opposite sides of the central acceleration plane 810 of the beam chamber. Current flowing through the one or more coils 825 generates a magnetic field perpendicular to the central acceleration plane 810 and having a radially increasing flux density. In one embodiment, the one or more coils 825 may be one or more superconducting coils. In one embodiment, the superconductor of the one or more coils 825 may be a high-temperature superconductor. In another embodiment, the superconductor of the one or more coils 825 may be an intermediate-temperature superconductor.

[0038] The isochronous cyclotron accelerator 800 may also include multiple structural sector pairs 840, 845 and multiple bulk superconductor sector pairs 850, 855. The multiple structural sector pairs 840, 845 and multiple bulk superconductor sector pairs 850, 855 may be disposed inside or outside the beam chamber and / or vacuum chamber. The multiple structural sector pairs 840, 845 and multiple bulk superconductor sector pairs 850, 855 may be disposed on opposite sides of the central acceleration plane 810. In one embodiment, the axial spacing between corresponding pairs of bulk superconductor sectors 850, 855 may be greater than or less than the axial spacing between corresponding pairs of structural sectors 840, 845. In one embodiment, the multiple structural sector pairs 840, 845 may be made of a magnetically neutral material, such as, but not limited to, metals, ceramics, glass fiber reinforced epoxy resin, carbon fiber reinforced polymers, or the like. In another embodiment, the plurality of structural sectors 840, 845 may be composed of ferromagnetic, paramagnetic, and / or diamagnetic materials, such as, but not limited to, iron. In one embodiment, the plurality of bulk superconductor sectors 850, 855 may include bulk high-temperature superconducting materials. In another embodiment, the bulk superconductor sectors 850, 855 may include bulk mid-temperature superconducting materials. Bulk high-temperature superconducting materials may include, but are not limited to, rare earth barium copper oxide (REBCO) (such as yttrium barium copper oxide (YBCO)), or gadolinium barium copper oxide (GdBCO), or europium barium copper oxide (EUBCO), lanthanum barium copper oxide (LBCO), and different types of bismuth strontium calcium copper oxide (BSCCO). Bulk mid-temperature superconducting materials may include, but are not limited to, magnesium diboride (MgB2) or iron (Fe)-based superconductors, also known as phosphorus group compounds. As used herein, the term bulk superconducting material refers to a superconducting material, as opposed to a structure comprising a combination of a superconducting material and a resistive conductor (such as copper, silver, etc.), which is also commonly referred to as a superconductor and is typically fabricated in the form of strips, ribbons, or wires. As used herein, high-temperature superconducting material refers to a material exhibiting superconductivity above about 40 Kelvin (K). As used herein, intermediate-temperature superconducting material refers to a material exhibiting superconductivity above about 25 Kelvin (K). In one embodiment, the plurality of bulk superconducting sector pairs 850, 855 may comprise bulk type II superconductors. In one embodiment, the bulk type II superconductors may be maintained in a mixed state by one or more coolers (not shown), which are thermally coupled to the plurality of bulk superconducting sector pairs 850, 855. The one or more coolers may comprise one or more electric coolers, a refrigerant bath, etc.

[0039] although Figure 8AFour structural sector pairs 840, 845 and four bulk superconducting sectors 850, 855 are shown, but the isochronous cyclotron accelerator 800 may include any number of structural sector pairs 840, 845 and bulk superconducting sector pairs 850, 855. Furthermore, the guidance and / or concentration of magnetic fields through the bulk superconducting sectors 850, 855, and consequently axial focusing through magnetic flux, can be a combination of bulk superconducting material type, sector size, shape and density, and other physical properties. For example, in one embodiment, the multiple structural sector pairs 840, 845 and the multiple bulk superconducting sector pairs 850, 855 may have wedge-shaped shape factors. In another embodiment, the multiple structural sector pairs 840, 845 and the multiple bulk superconducting sector pairs 850, 855 may have helical shape factors. In one embodiment, the multiple structural sector pairs 840, 845 and / or the multiple bulk superconducting sector pairs 850, 855 may have beveled edges. In one embodiment, the plurality of structural sector pairs 840, 845 and / or the plurality of bulk superconductor sector pairs 850, 855 may have raised edges. In one embodiment, the plurality of structural sector pairs 840, 845 and the plurality of bulk superconductor sector pairs 850, 855 may have substantially equal radial widths. In another embodiment, the plurality of structural sector pairs 840, 845 may have much wider radial widths than the plurality of bulk superconductor sector pairs 850, 855. In yet another embodiment, the plurality of structural sector pairs 840, 845 may have much narrower radial widths than the plurality of bulk superconductor sector pairs 850, 855. In one embodiment, the plurality of structural sector pairs 840, 845 and the plurality of bulk superconductor sector pairs 850, 855 may be substantially adjacent to each other. In another embodiment, a gap 865 may be provided between the plurality of structural sector pairs 840, 845 and the plurality of bulk superconductor sector pairs 850, 855. In one embodiment, the gap 865 between the plurality of structural sector pairs 840, 845 and the plurality of bulk superconductor sector pairs 850, 855 may be filled with a mechanically reinforcing material, such as glass fiber reinforced epoxy resin, carbon fiber reinforced polymer or the like.

[0040] A radio frequency drive circuit (not shown) can be configured to accelerate charged particles 820 in a beam chamber along an orbital trajectory 830 extending outward from the central axis. After acceleration along the orbital trajectory 830, the charged particles 820 can be output from the isochronous cyclotron 800 through one or more ports 835.

[0041] Now for reference Figure 9This diagram illustrates a portion of a beam cell according to various aspects of the present invention, comprising multiple pairs of structural sectors and multiple pairs of bulk superconducting sectors. Multiple pairs of structural sectors 940, 945 may be positioned on opposite sides of a central accelerating plane 910 of the beam cell. Multiple pairs of bulk superconducting sectors 950, 955 may also be positioned on opposite sides of the central accelerating plane 910. The bulk superconducting sectors 950, 955 may be positioned between adjacent pairs of structural sectors 940, 945. The multiple pairs of bulk superconducting sectors 950, 955 may be configured to guide and / or concentrate a magnetic field 960 from the multiple pairs of bulk superconducting sectors 950, 955 into the multiple pairs of structural sectors 940, 945. The guidance and / or concentration of the magnetic field 960 results in localized compaction and decompaction of the magnetic flux density (e.g., fluttering field), thereby providing an axial focusing component along the particle path.

[0042] In one embodiment, the plurality of bulk superconductor sectors 950, 955 may include bulk type II superconductors maintained in a mixed state. In the mixed state (e.g., above the lower critical magnetic field Hc1 but below the upper critical magnetic field Hc2), a portion of the magnetic field 960 can penetrate the bulk type II superconductor sectors 950, 955 to provide a lower magnetic flux, and other portions of the magnetic field 960 are directed and concentrated into structural sectors 940, 945, such as... Figure 9 As shown. In one embodiment, a magnetic field 960, guided by bulk type II superconductor sectors 950 and 955 and concentrated in a central acceleration plane 910, provides an axial focusing component of the magnetic field 960 near structural sectors 940 and 945.

[0043] In one embodiment, the plurality of structural sector pairs 940, 945 and the plurality of bulk superconductor sector pairs 950, 955 may have shape factors configured to further increase the axial focusing component of the magnetic field 960. For example, the plurality of bulk superconductor sector pairs 850, 855, 950, 955 and the plurality of structural sector pairs 840, 845, 940, 945 may have helical shapes that further provide an axial focusing component to the magnetic field 960.

[0044] Now for reference Figure 10 This paper illustrates a method for accelerating charged particles according to various aspects of the present technology. The method may include providing a plurality of bulk superconducting sector pairs at 1010. Each bulk superconducting sector pair may be positioned on opposite sides of the central acceleration plane of the beam chamber. Furthermore, the bulk superconducting sector pairs may be separated from each other along a radial arc of the beam chamber.

[0045] At 1020, a magnetic field can be provided in the beam cell. The magnetic field can have a magnetic flux density that increases radially from the central axis of the beam cell and can be oriented substantially perpendicular to the central acceleration plane. Multiple bulk superconductor sector pairs can be configured to guide and / or concentrate the magnetic field among the multiple bulk superconductor sector pairs.

[0046] At 1030, charged particles can be provided near the central axis of the beam chamber. In one embodiment, the charged particles can be protons. In other embodiments, the charged particles can be electrons. In yet another embodiment, the charged particles can be any type of ion (e.g., C+). At 1040, a radio frequency signal can be provided to accelerate the charged particles in the beam chamber in an orbital trajectory extending outward from the central axis of the beam chamber. Guiding and / or concentrating the provided magnetic field by multiple bulk superconducting sectors can provide beam-focusing oscillations in the provided magnetic field to counteract axial instabilities in the orbital trajectory.

[0047] Now for reference Figure 11 This illustrates a method for accelerating charged particles according to various aspects of the present invention. At 1110, the method may include providing a plurality of structural sector pairs and a plurality of bulk superconducting sector pairs. Each structural sector pair may be disposed on opposite sides of a central acceleration plane of a beam chamber. Similarly, each bulk superconducting sector pair may be disposed on opposite sides of a central acceleration plane. Furthermore, bulk superconducting sector pairs may be disposed between adjacent structural sector pairs. In one embodiment, the plurality of structural sector pairs may comprise a magnetically neutral material. In another embodiment, the plurality of structural sector pairs may comprise ferromagnetic, paramagnetic, and / or diamagnetic materials. In one embodiment, the plurality of bulk superconducting sector pairs may be configured for near-total magnetic field repulsion or partial magnetic field repulsion.

[0048] At 1120, a magnetic field can be provided in the beam chamber. The magnetic field can have a magnetic flux density that increases radially from the central axis of the beam chamber and can be oriented substantially perpendicular to the central acceleration plane. The plurality of bulk superconductor sector pairs can be configured to guide and / or concentrate the magnetic field from the plurality of bulk superconductor sector pairs into the plurality of structural sector pairs.

[0049] At 1130, charged particles can be provided near the central axis of the beam chamber. In one embodiment, the charged particles can be protons. In another embodiment, the charged particles can be electrons. In yet another embodiment, the charged particles can be any type of ion (e.g., C+). At 1140, a radio frequency signal can be provided to accelerate the charged particles in the beam chamber in an orbital trajectory extending outward from the central axis of the beam chamber. The magnetic field guidance and / or concentration provided by multiple bulk superconducting sectors can provide beam-focusing oscillations in the provided magnetic field to counteract axial instabilities in the orbital trajectory.

[0050] Now for reference Figure 12 An exemplary particle therapy system according to various aspects of the present technology is illustrated. The particle therapy system 1200 may include an isochronous cyclotron accelerator 1210, a conveyor line 1220, a gantry 1230, and a patient table 1240. The particle therapy system 1200 typically also includes many other components, such as beam guiding components, beam scanning components, beam measuring components, vacuum components, power supply components, cooling components, mechanical support components, gantry drive components, etc., which are unnecessary for understanding various aspects of the present technology and therefore will not be described further herein.

[0051] Based on the above... Figures 7A-7B , Figures 8A-8B , Figure 9 , Figure 10 and Figure 11 As described in the aspects of this technology, the isochronous cyclotron accelerator 1210 can be configured to generate a proton beam. The proton beam can be output from the isochronous cyclotron accelerator 1210 to a delivery line 1220. A gantry 1230 can be configured to rotate around a patient stage 1240 to deliver charged particles to a target area (such as a patient's cancer or tumor). By rotating the gantry 1230 around the patient on the patient stage 1240, a given dose can be delivered to the target area while reducing the dose delivered to surrounding tissues. Typically, the gantry 1230 can be configured to rotate ±180° around the patient stage 1040.

[0052] Based on various aspects of this technology, particle therapy systems are just one possible application of isochronous cyclotron accelerators. Other possible applications may include nuclear magnetic resonance (NMR), magnetic resonance imaging (MRI), accelerator magnets for high-energy physics (HEP) research, and nuclear fusion systems.

[0053] Various aspects of this technology can advantageously provide an increased axial focusing component of the magnetic field in an isochronous cyclotron. Therefore, the average flux density of the radially increased magnetic field in the beam chamber can be increased. This increased average flux density of the radially increased magnetic field can advantageously allow for an overall reduction in the size of the beam chamber and the isochronous cyclotron. Compared to sectors wound with superconducting coils, bulk superconducting sectors are passive and do not require current routing. The bulk superconducting shape in the bulk superconducting sector can also be easily manufactured using techniques such as machining (e.g., cutting and milling) or molding. Therefore, this increased axial focusing component can be provided by bulk superconducting sectors, which can be manufactured relatively easily and / or produced at a lower cost compared to other techniques for increasing the axial focusing component of the magnetic field in an isochronous cyclotron.

[0054] The following examples are specific technical embodiments and indicate specific features, elements, or steps that may be used or otherwise combined in implementing these embodiments.

[0055] Example 1 includes an isochronous cyclotron accelerator comprising: a beam chamber including a central axis and a central acceleration plane; a particle source coupled to the central acceleration plane near the central axis of the beam chamber; one or more coils disposed around the beam chamber; one or more radio frequency drive circuits coupled to the beam chamber; and a plurality of bulk superconductor sector pairs, wherein each bulk superconductor sector pair is disposed on opposite sides of the central acceleration plane.

[0056] Example 2 includes the isochronous cyclotron accelerator according to Example 1, and further includes: a plurality of structural sector pairs, wherein each structural sector pair is disposed on opposite sides of the central acceleration plane; and wherein a plurality of bulk superconductor sector pairs are disposed between adjacent structural sector pairs.

[0057] Example 3 includes an isochronous cyclotron accelerator according to Example 2, wherein multiple structural sector pairs include multiple magnetically neutral sector pairs.

[0058] Example 4 includes an isochronous cyclotron according to Example 2, wherein the multiple structural sector pairs include multiple ferromagnetic sector pairs, multiple paramagnetic sector pairs, or multiple antimagnetic sector pairs.

[0059] Example 5 includes an isochronous cyclotron accelerator according to Example 1, wherein multiple bulk superconductor sector pairs include bulk high-temperature superconductors.

[0060] Example 6 includes an isochronous cyclotron accelerator according to either Example 1 or 5, wherein a plurality of bulk superconductor sector pairs include bulk type II superconductors.

[0061] Example 7 includes an isochronous cyclotron according to Example 1, wherein one or more coils comprise a pair of coils surrounding the beam chamber and disposed on opposite sides of the central acceleration plane of the beam chamber.

[0062] Example 8 includes an isochronous cyclotron accelerator according to Example 1 or 7, wherein one or more coils include one or more superconducting coils.

[0063] Example 9 includes an isochronous cyclotron accelerator according to any one of Examples 1, 5 or 6, wherein multiple bulk superconductor sector pairs have a wedge shape.

[0064] Example 10 includes an isochronous cyclotron accelerator according to any one of Examples 1, 5 or 6, wherein multiple bulk superconductor sector pairs have a helical shape.

[0065] Example 11 includes an isochronous cyclotron comprising: one or more coils disposed around a beam chamber and configured to generate a magnetic field in the beam chamber having a magnetic flux density that increases radially from the central axis of the beam chamber and is oriented substantially perpendicular to a central acceleration plane; and a plurality of bulk superconducting sector pairs, wherein each bulk superconducting sector pair is disposed on opposite sides of the central acceleration plane, and wherein the plurality of bulk superconducting sector pairs are configured to guide or concentrate the magnetic field to provide an axially focused component of the magnetic field.

[0066] Example 12 includes the isochronous cyclotron accelerator according to Example 11, and further includes: a plurality of structural sector pairs, wherein each structural sector pair is disposed on opposite sides of the central acceleration plane of the beam chamber; and wherein a plurality of bulk superconductor sector pairs are disposed between adjacent structural sector pairs, and wherein the plurality of bulk superconductor sector pairs are configured to guide or concentrate a magnetic field into the beam chamber in the vicinity of the plurality of structural sector pairs.

[0067] Example 13 includes an isochronous cyclotron accelerator according to Example 12, wherein multiple structural sector pairs and multiple bulk superconductor sector pairs have shape factors configured to increase the axial focusing component of the magnetic field.

[0068] Example 14 includes an isochronous cyclotron accelerator according to Example 12, wherein the axial spacing between opposite pairs of these bulk superconducting sectors is less than and / or greater than the axial spacing between opposite pairs of these structural sectors.

[0069] Example 15 includes an isochronous cyclotron accelerator according to any one of Examples 11-14, wherein a plurality of bulk superconductor sector pairs include bulk high-temperature superconductors.

[0070] Example 16 includes an isochronous cyclotron accelerator according to any one of Examples 11-14, wherein a plurality of bulk superconductor sector pairs include bulk type II superconductors.

[0071] Example 17 includes an isochronous cyclotron accelerator according to any one of Examples 11-14, wherein multiple bulk superconductor sector pairs are maintained in a mixed state.

[0072] Example 18 includes an isochronous cyclotron according to any one of Examples 11-14, wherein one or more coils comprise a pair of coils surrounding a beam chamber and disposed on opposite sides of a central acceleration plane of the beam chamber.

[0073] Example 19 includes an isochronous cyclotron accelerator according to any one of Examples 11-14, wherein one or more coils include one or more superconducting coils.

[0074] Example 20 includes a method for accelerating charged particles, comprising: providing a plurality of bulk superconducting sector pairs, wherein each bulk superconducting sector pair is disposed on opposite sides of a central acceleration plane of a beam chamber, and wherein the bulk superconducting sector pairs are spaced apart from each other along a radial arc of the beam chamber; and providing a magnetic field in the beam chamber having a magnetic flux density that increases radially from the central axis of the beam chamber and is oriented substantially perpendicular to the central acceleration plane, wherein the plurality of bulk superconducting sector pairs are configured to guide or concentrate the magnetic field among the plurality of bulk superconducting sector pairs.

[0075] Example 21 includes the charged particle acceleration method of Example 20, and further includes: providing a plurality of structural sector pairs, wherein each structural sector pair is disposed on opposite sides of the central acceleration plane of the beam chamber, and wherein a bulk superconductor sector pair is disposed between adjacent structural sector pairs.

[0076] Example 22 includes the charged particle acceleration method of Example 20, further comprising: providing charged particles near the central axis of the beam chamber; and providing a radio frequency signal configured to accelerate the charged particles in the beam chamber in an orbital trajectory extending outward from the central axis of the beam chamber.

[0077] Example 23 includes a charged particle acceleration method of any of Examples 20-22, wherein a plurality of bulk superconductor sector pairs include bulk high-temperature superconductors.

[0078] Example 24 includes a charged particle acceleration method of any of Examples 20-22, wherein a plurality of bulk superconductor sector pairs include bulk type II superconductors.

[0079] Example 25 includes a charged particle acceleration method of any of Examples 20-22, wherein the provided magnetic field is higher than the lower critical magnetic field Hc1 of the bulk superconducting material in the bulk superconducting sector and lower than the upper critical magnetic field Hc2.

[0080] The foregoing description of specific embodiments of the present technology has been presented for illustrative and descriptive purposes. These descriptions are not intended to be exhaustive or to limit the technology to the precise forms disclosed, and it will be apparent that many modifications and variations are possible in accordance with the above teachings. These embodiments were chosen and described in order to best explain the principles of the present technology and its practical application, thereby enabling others skilled in the art to best utilize the present technology and its various embodiments with various modifications suitable for the intended particular use. The scope of the invention is intended to be defined by the appended claims and their equivalents.

Claims

1. An isochronous cyclotron accelerator, the accelerator comprising: One or more coils, arranged around a beam chamber and configured to generate a magnetic field in the beam chamber, the magnetic field having a magnetic flux density that increases radially from the central axis of the beam chamber and being oriented substantially perpendicular to the central acceleration plane; and Multiple passive bulk superconductor sector pairs, wherein each passive bulk superconductor sector pair is disposed on opposite sides of a central acceleration plane, and wherein the multiple passive bulk superconductor sector pairs are configured to guide or concentrate the magnetic field to provide an axial focusing component of the magnetic field.

2. The isochronous cyclotron accelerator according to claim 1, further comprising: The beam chamber includes a central axis and a central acceleration plane; A particle source, which is coupled to the central acceleration plane near the central axis of the beam chamber; and One or more radio frequency drive circuits are coupled to the beam chamber.

3. The isochronous cyclotron accelerator according to claim 1 or 2, further comprising: Multiple structural sector pairs, wherein each structural sector pair is positioned on opposite sides of the central acceleration plane; as well as The plurality of passive bulk superconductor sector pairs are arranged between adjacent structural sector pairs.

4. The isochronous cyclotron accelerator of claim 3, wherein the plurality of passive bulk superconductor sector pairs are configured to: guide or concentrate the magnetic field into the beam chamber in the vicinity of the plurality of structural sector pairs.

5. The isochronous cyclotron accelerator of claim 3, wherein the plurality of structural sector pairs and the plurality of passive bulk superconductor sector pairs have shape factors configured to increase the axial focusing component of the magnetic field.

6. The isochronous cyclotron accelerator according to claim 3, wherein the axial spacing between corresponding pairs of the passive bulk superconductor sectors is less than or greater than the axial spacing between corresponding pairs of the structural sectors.

7. The isochronous cyclotron accelerator according to claim 3, wherein the plurality of structural sector pairs comprises a plurality of magnetically neutral sector pairs.

8. The isochronous cyclotron accelerator according to claim 3, wherein the plurality of structural sector pairs comprises a plurality of ferromagnetic pairs, a plurality of paramagnetic pairs, or a plurality of antimagnetic sector pairs.

9. The isochronous cyclotron accelerator according to claim 1 or 2, wherein the plurality of passive bulk superconductor sector pairs comprises bulk high-temperature superconductors.

10. The isochronous cyclotron accelerator according to claim 1 or 2, wherein the plurality of passive bulk superconductor sector pairs comprise bulk type II superconductors.

11. The isochronous cyclotron accelerator according to claim 1 or 2, wherein the one or more coils comprise a pair of coils surrounding the beam chamber and disposed on opposite sides of the central acceleration plane of the beam chamber.

12. The isochronous cyclotron accelerator according to claim 1 or 2, wherein the one or more coils comprise one or more superconducting coils.

13. The isochronous cyclotron accelerator according to claim 1 or 2, wherein the plurality of passive bulk superconductor sector pairs have a wedge shape.

14. The isochronous cyclotron accelerator according to claim 1 or 2, wherein the plurality of passive bulk superconductor sectors have a helical shape.

15. The isochronous cyclotron accelerator according to claim 1 or 2, wherein the plurality of passive bulk superconductor sector pairs are maintained in a mixed state.

16. A method for accelerating charged particles, the method comprising: Provided are multiple pairs of passive bulk superconducting sectors, wherein each pair of passive bulk superconducting sectors is disposed on opposite sides of the central acceleration plane of a beam chamber, and wherein the pairs of passive bulk superconducting sectors are spaced apart from each other along a radial arc of the beam chamber; and A magnetic field is provided in the beam chamber having a magnetic flux density that increases radially from the central axis of the beam chamber and is oriented substantially perpendicular to the central acceleration plane, wherein the plurality of passive bulk superconductor sector pairs are configured to guide or concentrate the magnetic field between the plurality of passive bulk superconductor sector pairs.

17. The charged particle acceleration method according to claim 16, further comprising: Multiple structural sector pairs are provided, wherein each structural sector pair is disposed on opposite sides of the central acceleration plane of the beam chamber, and wherein the passive bulk superconductor sector pairs are disposed between adjacent structural sector pairs.

18. The charged particle acceleration method according to claim 16 or 17, further comprising: Charged particles are provided near the central axis of the beam chamber; as well as A radio frequency signal is provided, the radio frequency signal being configured to accelerate the charged particles in the beam chamber in an orbital trajectory extending outward from the central axis of the beam chamber.

19. The charged particle acceleration method according to claim 16 or 17, wherein the plurality of passive bulk superconductor sector pairs comprises bulk high-temperature superconductors.

20. The method for accelerating charged particles according to any one of claims 16 or 17, wherein the plurality of passive bulk superconductor sector pairs comprise bulk type II superconductors.

21. The charged particle acceleration method according to any one of claims 16 or 17, wherein the provided magnetic field is higher than the lower critical magnetic field Hc1 of the bulk superconducting material of the passive bulk superconducting sector and lower than the upper critical magnetic field Hc2 of the bulk superconducting material of the passive bulk superconducting sector.

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