Ion beam path on target surface for neutron beam generation.

Abstract

Embodiments of the system, device, and method relate to selecting a raster profile for scanning a proton beam across a target. The raster profile is selected from among multiple possible raster profiles based on a figure of merit value. The beam is directed across the target surface, forming a pattern that is repeated one or more times at different radial orientations to form a scan profile. The target temperature is monitored while the beam is scanned across the target surface according to the scan profile. Scan parameters can be varied to avoid target damage, improve thermal performance, and optimize particle loading.

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Application No. 63 / 070,789, filed Aug. 26, 2020, the contents of which are incorporated herein by reference.

[0002] The subject matter described herein relates generally to systems, devices, and methods for determining and directing an ion beam path on a target surface, and more particularly, to systems, devices, and methods for determining and directing an ion beam path on a target surface for neutron beam generation. [Background technology]

[0003] Boron neutron capture therapy (BNCT) is a modality for the treatment of various types of cancer, including some of the most difficult types. BNCT is a technique that uses boron compounds to selectively target tumor cells to treat while sparing normal cells. The boron compounds allow for efficient uptake by various cell types and selective drug accumulation at target sites, such as tumor cells. The boron-loaded cells can be irradiated with neutrons (e.g., in the form of a neutron beam). The neutrons react with the boron and kill the tumor cells.

[0004] Neutron beams for BNCT can be generated by irradiating a suitable target with an ion beam, such as a proton beam. The ions react with atomic nuclei in the target, releasing a beam of neutrons that can be used for BNCT. Exposure of the target to the ion beam for long periods can result in degradation of the target and the resulting neutron beam. The target can be replaced, but this is expensive and can result in system downtime. Thus, there is a need for improved proton beam delivery to extend the functionality of the target below temperature limits and reduce system downtime. Summary of the Invention [Means for solving the problem]

[0005] Exemplary embodiments of the systems, devices, and methods described herein relate to the selection of a profile for scanning an ion beam (e.g., a proton beam) across a target surface. In some implementations, the beam path across the target surface forms a first pattern. The pattern, also called a base pattern or cycle, is repeated one or more times at different radial orientations from the first instance of the pattern to form a scan profile. Here, "radial" orientation refers to an orientation in a cylindrical coordinate system, or alternatively, a circumferential direction. The embodiments include at least two instances of a first beam pattern that are radially offset from each other. The various instances of the beam pattern can be offset by a certain amount such that the scan profile includes instances of the pattern that are clockwise rotated at regular radial intervals. The embodiments are based on computational modeling that is configured to improve thermal performance and particle loading, among other advantages. For example, computational modeling can allow for the selection of a beam scan (or raster) profile that improves the uniformity of the particle load on the target and / or can allow for the selection of a scan profile that reduces (e.g., minimizes) the peak transient temperature of the target. The computational model shows the thermal effect on the target of several beam parameters, such as the size and shape of the beam. The computational model can include a mesh-like space that encompasses the target. The mesh consists of a three-dimensional grid in which the thermal load on the target is modeled. Temperature values ​​are obtained by solving a one-dimensional heat transport equation at each "pixel" (element) of the grid. The one-dimensional heat transport equation is solved for heat transport through the depth of the pixel, taking into account that crosstalk between pixels or lateral heat conduction between pixels is assumed to be negligible. Numerical approaches used to solve the one-dimensional heat transport differential equation include finite element and finite difference methods. For either the finite element and finite difference techniques, the target is represented in plan view as part of a grid. The grid can have the same unit cell size in each dimension, or the size in each dimension can be different.The resolution can be selected to provide the ability to model beams of different sizes and configurations to suit the physical capabilities of the system under study. The computational model allows for the selection of a scan profile that defines a path for the proton beam that has a minimum delay between successive exposures of a single location of the target to the proton beam that exceeds a threshold period. The selected profile can define a path based on a trochoidal shape that includes multiple lobes. The computational model allows for the selection of a profile with various angular frequencies of the proton beam among different lobes of the trochoidal shape. The computational model allows for the selection of a profile with various angular velocities of the proton beam across the target surface. The computational model allows for the selection of a scan profile with various linear velocities of the proton beam across the target surface.

[0006] In one aspect, this document describes a method of scanning a beam across a scannable surface of a target along a first path and scanning a beam across the scannable surface of a target along a second path, the first path forming a first pattern in a first radial orientation and the second path forming the first pattern in a second radial orientation substantially different from the first radial orientation. The beam can be pulsed while scanning along the first and second paths. The beam propagates continuously while scanning along the first and second paths. The beam moves from an inner region of the scannable surface to an outer region and back to the inner region in the first pattern. The beam moves from an outer region of the scannable surface to an inner region and back to the outer region in the first pattern. The first pattern can include a spiral and a mirror image of the spiral. The first pattern has a first half and a second half, the first and second halves being symmetrical. The first pattern can be continuously curved. The first pattern has a start location and a stop location, and the start location can be at or adjacent to the stop location. The first radial orientation differs from the second radial orientation by 180 degrees. The operations can further include scanning the beam across the scannable surface of the target along a third path, the third path forming the first pattern at a third radial orientation different from the first and second radial orientations. The first, second, and third radial orientations differ by 120 degrees. The operations can further include scanning the beam across the scannable surface of the target along a fourth path, the fourth path forming the first pattern at a fourth radial orientation different from the first, second, and third radial orientations. The first, second, third, and fourth radial orientations differ by 90 degrees. The operations may further include scanning the beam across the scannable surface of the target along a fifth pass, the fifth pass forming the first pattern at a fifth radial orientation different from the first, second, third, and fourth radial orientations. The first, second, third, fourth, and fifth radial orientations differ by 72 degrees. The first pass corresponds to a first instance of the cycle and the second pass corresponds to a second instance of the cycle.In some implementations, the scanning of the first instance of the cycle and the second instance of the cycle form a closed loop. The beam can be a proton beam. The scannable surface can be a lithium or beryllium surface. The target generates neutrons when scanned. The beam has a circular cross-sectional profile. The beam has an elliptical cross-sectional profile. The beam has an annular cross-sectional profile. The beam has a hollow cross-sectional profile. The operation performs boron neutron capture therapy (BNCT). The beam can be generated by a beam system including an ion source, a first beamline coupled to the ion source, a tandem accelerator coupled to the first beamline, a second beamline coupled to the tandem accelerator, and a target coupled to the second beamline. The pattern exposes a majority of the scannable surface to the beam. The second pass forms the first pattern at a second radial orientation different from the first radial orientation.

[0007] In another aspect, this document describes a method of operating a beam that includes scanning the beam across a scannable surface of a target along a first path, and scanning the beam across the scannable surface of the target along a second path, where the first path forms a first pattern at a first radial orientation and the second path forms a second pattern at a second radial orientation different from the first radial orientation, where the first and second patterns are substantially identical except for the different radial orientation. The first and second patterns are identical except for the different radial orientation.

[0008] In another aspect, the document describes a beam system including a computing device including a processor communicatively coupled to a memory, the memory storing a plurality of instructions that, when executed by the processor, causes the processor to control movement of a beam across a scannable surface of a target along a first path and control movement of a beam across a scannable surface of a target along a second path, the first path can include a first pattern in a first radial orientation, and the second path can include the first pattern substantially in a second radial orientation different from the first radial orientation. The first path passes from an inner region of the scannable surface to an outer region and back to the inner region in the first pattern. The first path passes from an outer region of the scannable surface to an inner region and back to the outer region in the first pattern. The first pattern can include a spiral and a mirror image of the spiral. The first pattern can include a first half and a second half, the first and second halves being symmetrical. The first pattern can be continuously curved. The first pattern can include a start location and a stop location, and the start location can be at or adjacent to the stop location. The first radial orientation differs from the second radial orientation by 180 degrees. The instructions, when executed by the processor, can further cause the processor to control movement of the beam across the scannable surface of the target along a third path, the third path can include the first pattern at a third radial orientation different from the first and second radial orientations. The first, second, and third radial orientations differ by 120 degrees. The instructions, when executed by the processor, can further cause the processor to control movement of the beam across the scannable surface of the target along a fourth path, the fourth path can include the first pattern at a fourth radial orientation different from the first, second, and third radial orientations. The first, second, third, and fourth radial orientations differ by 90 degrees.The instructions of the system, when executed by the processor, further cause the processor to control movement of the beam across the scannable surface of the target along a fifth path, the fifth path can include the first pattern at a fifth radial orientation different from the first, second, third, and fourth radial orientations. The first, second, third, fourth, and fifth radial orientations differ by 72 degrees. The instructions, when executed by the processor, further cause the processor to control movement of the beam across the scannable surface of the target along a sixth path, the sixth path can include the first pattern at a sixth radial orientation different from the first, second, third, fourth, and fifth radial orientations. The first, second, third, fourth, fifth, and sixth radial orientations differ by 60 degrees. The beam can be a proton beam. The scannable surface can be a surface of a lithium layer or a beryllium layer. The target generates neutrons when scanned. The beam can include a circular profile. The beam can include an elliptical profile. The beam can include an annular profile. The beam can include a hollow profile. The operation is performed in boron neutron capture therapy (BNCT). The beam can be generated by a beam system including an ion source, a first beamline coupled to the ion source, a tandem accelerator coupled to the first beamline, a second beamline coupled to the tandem accelerator, and a target coupled to the second beamline. The first pattern exposes a majority of the scannable surface to the beam. The second pass forms the first pattern at a second radial orientation different from the first radial orientation.

[0009] In another aspect, this document describes a computer-implemented method for selecting a raster profile for scanning a proton beam across a target, the method including: establishing, using a computer processing system, a plurality of possible raster profiles for scanning a proton beam across a target, each of the plurality of possible raster profiles including one or more beam parameters, each of the one or more beam parameters characterizing a property of the proton beam and one or more path parameters characterizing a path of the proton beam across the target; establishing, using the computer processing system, one or more target parameters characterizing the target; calculating, using the computer processing system, a figure of merit value for each possible beam raster profile, the figure of merit may be based on a thermal loading of the target by the proton beam for a corresponding possible raster profile; using the computer processing system, selecting a raster profile from among the plurality of possible raster profiles based on the figure of merit value; and directing the proton beam across the target according to the selected raster profile. The step of calculating a value for the figure of merit may include calculating, for each possible raster profile, a heat load in each of a plurality of discrete portions of the target based on a linear relationship between heat load and proton flux in each discrete portion for the corresponding raster profile. Each discrete portion corresponds to an area of ​​a surface of the target in a path of the proton beam, which may be smaller than a dimension of the proton beam. The heat load in each discrete portion may be calculated based on heat transfer through a depth of the target away from a surface of the target on which the proton beam may be incident. The figure of merit may be selected from the group consisting of a peak temperature of the target, a temperature change of the target, an average temperature of the target, and a utilization efficiency of the target. The one or more beam parameters are selected from the group consisting of a beam dimension, a beam shape, and a beam configuration. The beam dimension may be in the range of 10 mm to 30 mm. The beam shape may be circular or elliptical.The beam may be circular or annular in configuration. The one or more path parameters may be selected from the group consisting of a frequency associated with the path of the proton beam, a linear velocity of the proton beam across the surface of the target, a number of radial scan layers in a supercycle of the path of the proton beam, and a number of supercycles of the path of the proton beam. The one or more target parameters may be selected from the group consisting of a target surface area, a target thickness, and a target composition. The target may include a layer of lithium or a layer of beryllium. The target may include a layer of metal supporting a layer of lithium or a layer of beryllium. The selecting step may include presenting a list of possible raster profiles to an operator of the proton beam and receiving a selection from the list by the operator via the computer system. The operations may further include measuring one or more properties of the target and selecting a raster profile based on the measured properties of the target. The one or more properties of the target comprise a temperature of the target at one or more locations on the target. The operations may further include measuring one or more properties of the beam and selecting a raster profile based on the measured properties of the beam. One or more properties of the beam are measured upstream from the target. The selected raster profile defines a path for the proton beam having a minimum delay between successive exposures of a single location of the target to the proton beam that exceeds a threshold period. The selected raster profile defines a path based on a trochoidal shape. The trochoidal shape can include multiple lobes. The angular frequency of the proton beam varies for different lobes of the trochoidal shape. The selected raster profile can include various angular velocities of the proton beam across the target surface. The selected raster profile can include various linear velocities of the proton beam across the target surface.

[0010] In another aspect, this document describes a computer-implemented method that includes monitoring a temperature of a target while scanning a proton beam across a surface of the target according to a first raster profile, and changing the scan from the first raster profile to a second raster profile based on the monitored temperature, where the second raster profile and the first raster profile result in different heating profiles of the target according to a computer model of the thermal loading of the target by the first and second raster profiles. The scan can be changed in response to a selection of the second raster profile from among a plurality of raster profiles by a human operator of the proton beam. The scan can be changed automatically according to a feedback or feedforward algorithm. The temperature can be monitored at a plurality of discrete locations of the target. The temperature can be monitored by acquiring a thermal image of the target.

[0011] In another aspect, this document describes a method of operating a beam that includes scanning a charged particle beam across a scannable surface of a target in a supercycle, where the supercycle can include multiple cycles, each cycle of the multiple cycles having the same shape and a different azimuthal orientation, and the multiple cycles are linked together such that a path of the charged particle beam passes through the multiple cycles in a closed loop. The multiple cycles can include two cycles azimuthally offset by 180 degrees from each other. The multiple cycles can include three cycles azimuthally offset by 120 degrees from each other. The multiple cycles can include four cycles azimuthally offset by 90 degrees from each other.

[0012] Other systems, devices, methods, features, and advantages of the subject matter described herein will be, or will become, apparent to one of ordinary skill in the art upon examination of the following figures and detailed description. All such additional systems, methods, features, and advantages are intended to be included within this description, be within the scope of the subject matter described herein, and be protected by the accompanying claims. Features of the example embodiments should not be construed as limiting the appended claims in any way, even if the features are absent from the claims. The present invention provides, for example, the following: (Item 1) 1. A method of operating a beam, comprising the steps of: scanning the beam across a scannable surface of a target along a first path; scanning the beam across a scannable surface of the target along a second path, the first path forming a first pattern at a first radial orientation and the second path forming substantially the first pattern at a second radial orientation different from the first radial orientation; A method comprising: (Item 2) 2. The method of claim 1, wherein the beam is pulsed while scanning along the first and second paths. (Item 3) 2. The method of claim 1, wherein the beam propagates continuously while scanning along the first and second paths. (Item 4) Item 14. The method of item 1, wherein the beam moves from an inner region to an outer region of the scannable surface and back to the inner region in the first pattern. (Item 5) Item 1 . The method of item 1 , wherein the beam moves from an outer region to an inner region of the scannable surface and back to the outer region in the first pattern. (Item 6) Item 2. The method of item 1, wherein the first pattern comprises a spiral and a mirror image of the spiral. (Item 7) Item 2. The method of item 1, wherein the first pattern has a first half and a second half, and the first and second halves are symmetrical. (Item 8) Item 2. The method of item 1, wherein the first pattern is continuously curved. (Item 9) 2. The method of claim 1, wherein the first pattern has a start location and a stop location, the start location being at or adjacent to the stop location. (Item 10) 2. The method of claim 1, wherein the first radial orientation differs from the second radial orientation by 180 degrees. (Item 11) scanning the beam across a scannable surface of the target along a third path, the third path forming the first pattern at a third radial orientation different from the first and second radial orientations. The method of claim 1, further comprising: (Item 12) Item 2. The method of item 1, wherein the first, second, and third radial orientations differ by 120 degrees. (Item 13) scanning the beam across a scannable surface of the target along a fourth path, the fourth path forming the first pattern at a fourth radial orientation different from the first, second, and third radial orientations. 12. The method of claim 11, further comprising: (Item 14) Item 14. The method of item 13, wherein the first, second, third, and fourth radial orientations differ by 90 degrees. (Item 15) scanning the beam across a scannable surface of the target along a fifth path, the fifth path forming the first pattern at a fifth radial orientation different from the first, second, third, and fourth radial orientations. Item 14. The method of item 13, further comprising: (Item 16) Item 16. The method of item 15, wherein the first, second, third, fourth, and fifth radial orientations differ by 72 degrees. (Item 17) 2. The method of claim 1, wherein the first pathway corresponds to a first instance of a cycle and the second pathway corresponds to a second instance of the cycle. (Item 18) 20. The method of claim 17, wherein the scanning of the first instance of the cycle and the second instance of the cycle forms a closed loop. (Item 19) 19. The method according to any of items 1-18, wherein the beam is a proton beam. (Item 20) 20. The method of any of items 1-19, wherein the scannable surface is a lithium or beryllium surface. (Item 21) 21. The method of any of items 1-20, wherein the target generates neutrons when scanned. (Item 22) 22. The method of any of items 1-21, wherein the beam is scanned across the scannable surface of the target along a plurality of paths, the plurality of paths comprising the first and second paths, a quantity (N) of paths in the plurality of paths being two or more, the N paths together forming a closed loop, and each of the N paths forming substantially the first pattern being radially offset by 360 / N degrees from adjacent ones of the paths. (Item 23) 22. The method of any of items 1-21, wherein the beam has a circular or elliptical cross-sectional profile. (Item 24) 22. The method of any of items 1-21, wherein the beam has an annular cross-sectional profile. (Item 25) 22. The method of any of items 1-21, wherein the beam has a hollow cross-sectional profile. (Item 26) The method according to any one of items 1 to 25, which is carried out in boron neutron capture therapy (BNCT). (Item 27) The beam is An ion source; a first beamline coupled to the ion source; a tandem accelerator coupled to the first beamline; a second beamline coupled to the tandem accelerator; The target coupled to the second beamline. 27. The method according to any of items 1-26, wherein the method is generated by a beam system comprising: (Item 28) 28. The method of claim 1, wherein the first pattern exposes a majority of the scannable surface to the beam. (Item 29) 29. The method of claim 1, wherein the second path forms the first pattern at the second radial orientation different from the first radial orientation. (Item 30) 1. A method of operating a beam, comprising the steps of: scanning the beam across a scannable surface of a target along a first path; scanning the beam across a scannable surface of the target along a second path, the first path forming a first pattern at a first radial orientation and the second path forming a second pattern at a second radial orientation different from the first radial orientation, the first and second patterns being substantially identical except for the different radial orientation; A method comprising: (Item 31) Item 31. The method of item 30, wherein the first and second patterns are identical except for the different radial orientations. (Item 32) The method according to any one of items 2-29, comprising the steps of: (Item 33) 1. A beam system comprising: 1. A computing device comprising: a processor communicatively coupled to a memory, the memory storing a plurality of instructions that, when executed by the processor, cause the processor to: Controlling movement of the beam across a scannable surface of the target along a first path; controlling movement of the beam across a scannable surface of the target along a second path, the first path comprising a first pattern at a first radial orientation and the second path comprising substantially the first pattern at a second radial orientation different from the first radial orientation; A computing device that A system comprising: (Item 34) Item 34. The system of item 33, wherein the first path passes from an inner region to an outer region of the scannable surface and back to the inner region in the first pattern. (Item 35) Item 34. The system of item 33, wherein the first path passes from an outer region to an inner region of the scannable surface and back to the outer region in the first pattern. (Item 36) Item 34. The system of item 33, wherein the first pattern comprises a spiral and a mirror image of the spiral. (Item 37) Item 34. The system of item 33, wherein the first pattern has a first half and a second half, the first and second halves being symmetrical. (Item 38) Item 34. The system of item 33, wherein the first pattern is continuously curved. (Item 39) Item 34. The system of item 33, wherein the first pattern has a start location and a stop location, the start location being at or adjacent to the stop location. (Item 40) Item 34. The system of item 33, wherein the first radial orientation differs from the second radial orientation by 180 degrees. (Item 41) The instructions, when executed by the processor, further cause the processor to: controlling movement of the beam across a scannable surface of the target along a third path, the third path comprising the first pattern at a third radial orientation different from the first and second radial orientations; Item 34. The system according to item 33, (Item 42) Item 42. The system of item 41, wherein the first, second, and third radial orientations differ by 120 degrees. (Item 43) The instructions, when executed by the processor, further cause the processor to: controlling movement of the beam across a scannable surface of the target along a fourth path, the fourth path comprising the first pattern at a fourth radial orientation different from the first, second, and third radial orientations; Item 42. The system according to item 41, (Item 44) Item 44. The system of item 43, wherein the first, second, third, and fourth radial orientations differ by 90 degrees. (Item 45) The instructions, when executed by the processor, further cause the processor to: controlling movement of the beam across a scannable surface of the target along a fifth path, the fifth path comprising the first pattern at a fifth radial orientation different from the first, second, third, and fourth radial orientations; Item 44. The system according to item 43, (Item 46) Item 46. The system of item 45, wherein the first, second, third, fourth, and fifth radial orientations differ by 72 degrees. (Item 47) The instructions, when executed by the processor, further cause the processor to: controlling movement of the beam across a scannable surface of the target along a sixth path, the sixth path comprising the first pattern at a sixth radial orientation different from the first, second, third, fourth, and fifth radial orientations; Item 46. The system according to item 45, (Item 48) Item 48. The system of item 47, wherein the first, second, third, fourth, fifth, and sixth radial orientations differ by 60 degrees. (Item 49) 49. The system of any of items 33-48, wherein the beam is a proton beam. (Item 50) 50. The system of any of claims 33-49, wherein the scannable surface is a surface of a lithium layer or a beryllium layer. (Item 51) 51. The system of any of claims 33-50, wherein the target generates neutrons when scanned. (Item 52) The instructions, when executed by the processor, cause the processor to: controlling movement of the beam across a scannable surface of the target along a plurality of paths, the plurality of paths including the first and second paths, a number (N) of paths in the plurality of paths being two or more, the N paths together forming a closed loop, each of the N paths forming the first pattern being substantially radially offset by 360 / N degrees from an adjacent one of the paths; The system according to any one of items 33-51, (Item 53) 52. The system of any of claims 33-51, wherein the beam has a circular profile or an elliptical profile. (Item 54) 52. The system of any of claims 33-51, wherein the beam has an annular profile. (Item 55) 52. The system of any of claims 33-51, wherein the beam has a hollow profile. (Item 56) The system according to any one of items 33-55, which is implemented in boron neutron capture therapy (BNCT). (Item 57) The beam is An ion source; a first beamline coupled to the ion source; a tandem accelerator coupled to the first beamline; a second beamline coupled to the tandem accelerator; The target coupled to the second beamline. 57. The system according to any of items 33-56, wherein the beam is generated by a beam system comprising: (Item 58) 58. The system of claim 33-57, wherein the first pattern exposes a majority of the scannable surface to the beam. (Item 59) 59. The system of claim 33-58, wherein the second path forms the first pattern at the second radial orientation different from the first radial orientation. (Item 60) 1. A computer-implemented method for selecting a raster profile for scanning a proton beam across a target, the method comprising: using a computer processing system to establish a plurality of possible raster profiles for scanning the proton beam across the target, each of the plurality of possible raster profiles comprising one or more beam parameters, each of the one or more beam parameters characterizing a property of the proton beam and one or more path parameters characterizing a path of the proton beam across the target; establishing, using the computer processing system, one or more target parameters that characterize the target; calculating, using the computer processing system, a figure of merit value for each of the potential beam raster profiles, the figure of merit being based on a thermal loading of the target by the proton beam with respect to the corresponding potential raster profile; selecting, using the computer processing system, a raster profile from among the plurality of possible raster profiles based on the value of the figure of merit; directing the proton beam across the target according to the selected raster profile; A method comprising: (Item 61) Item 61. The computer-implemented method of item 60, wherein calculating a value for the figure of merit includes calculating, for each of the possible raster profiles, a thermal load in each of a plurality of discrete portions of the target based on a linear relationship between the thermal load and proton flux in each discrete portion for the corresponding raster profile. (Item 62) Item 62. The computer-implemented method of item 61, wherein each discrete portion corresponds to an area of ​​the surface of the target within a path of the proton beam that is smaller than a dimension of the proton beam. (Item 63) Item 63. The computer-implemented method of item 62, wherein the heat load in each discrete portion is calculated based on heat transfer through a depth of the target away from a surface of the target on which the proton beam is incident. (Item 64) Item 61. The computer-implemented method of item 60, wherein the figure of merit is selected from the group consisting of a peak temperature of the target, a temperature change of the target, an average temperature of the target, and a utilization efficiency of the target. (Item 65) Item 61. The computer-implemented method of item 60, wherein the one or more beam parameters are selected from the group consisting of beam dimensions, beam shape, and beam structure. (Item 66) Item 66. The computer-implemented method of item 65, wherein selecting the raster profile from among the plurality of possible raster profiles based on the value of the figure of merit includes selecting a masked profile configured to avoid one or more portions of the target. (Item 67) Item 66. The computer-implemented method of item 65, wherein the beam dimension is in the range of 10 mm to 30 mm. (Item 68) Item 66. The computer-implemented method of item 65, wherein the beam shape is circular or elliptical and the structure of the beam is circular or annular. (Item 69) Item 61. The computer-implemented method of item 60, wherein the one or more path parameters are selected from the group consisting of a frequency associated with a path of the proton beam, a linear velocity of the proton beam across a surface of the target, a number of radial scan layers in a supercycle of a path of the proton beam, and a number of supercycles of a path of the proton beam. (Item 70) Item 61. The computer-implemented method of item 60, wherein the one or more target parameters are selected from the group consisting of target surface area, target thickness, and target composition. (Item 71) Item 61. The computer-implemented method of item 60, wherein the target comprises a layer of lithium or a layer of beryllium. (Item 72) Item 61. The computer-implemented method of item 60, wherein the target comprises a layer of metal supporting the layer of lithium or the layer of beryllium. (Item 73) Item 61. The computer-implemented method of item 60, wherein selecting includes presenting a list of the possible raster profiles to an operator of the proton beam and receiving, via the computer system, a selection from the list by the operator. (Item 74) Item 61. The computer-implemented method of item 60, further comprising measuring one or more properties of the target and selecting the raster profile based on the measured properties of the target. (Item 75) 75. The computer-implemented method of claim 74, wherein the one or more properties of the target comprise a temperature of the target at one or more locations on the target. (Item 76) Item 61. The computer-implemented method of item 60, further comprising measuring one or more properties of the beam and selecting the raster profile based on the measured properties of the beam. (Item 77) Item 77. The computer-implemented method of item 76, wherein one or more properties of the beam are measured upstream from the target. (Item 78) Item 61. The computer-implemented method of item 60, wherein the selected raster profile defines a path for the proton beam having a minimum delay between successive exposures of a single location of the target to the proton beam that exceeds a threshold period. (Item 79) Item 79. The computer-implemented method of item 78, wherein the selected raster profile defines a path that is based on a trochoidal shape. (Item 80) 80. The computer-implemented method of claim 79, wherein the trochoidal shape comprises multiple lobes. (Item 81) Item 81. The computer-implemented method of item 80, wherein an angular frequency of the proton beam varies for different lobes of the trochoidal shape. (Item 82) Item 61. The computer-implemented method of item 60, wherein the selected raster profile comprises different angular velocities of the proton beam across the target surface. (Item 83) Item 61. The computer-implemented method of item 60, wherein the selected raster profile comprises different linear velocities of the proton beam across the target surface. (Item 84) 1. A computer-implemented method, comprising: monitoring a temperature of the target while scanning the proton beam across a surface of the target according to a first raster profile; modifying the scan from the first raster profile to a second raster profile based on the monitored temperature; Including, The method, wherein the second raster profile and the first raster profile result in different heating profiles of the target according to a computer model of thermal loading of the target by the first and second raster profiles. (Item 85) Item 85. The computer-implemented method of item 84, wherein the scan is altered in response to a selection of the second raster profile from among a plurality of raster profiles by a human operator of the proton beam. (Item 86) Item 85. The computer-implemented method of item 84, wherein the scanning is automatically altered according to a feedback or feedforward algorithm. (Item 87) Item 85. The computer-implemented method of item 84, wherein the temperature is monitored at a plurality of discrete locations of the target. (Item 88) Item 85. The computer-implemented method of item 84, wherein the temperature is monitored by acquiring a thermal image of the target. (Item 89) A system for selecting a raster profile, the system comprising a plurality of modules configured to perform the computer-implemented method according to any one of items 60-88. (Item 90) 1. A method of operating a beam, comprising the steps of: Scanning a charged particle beam across a scannable surface of a target in a supercycle, the supercycle comprising a plurality of cycles, each cycle of the plurality of cycles having an identical shape and a different azimuthal orientation, the plurality of cycles being linked together such that a path of the charged particle beam passes through the plurality of cycles in a closed loop. A method comprising: (Item 91) Item 91. The method of item 90, wherein the plurality of cycles comprises two cycles azimuthally offset by 180 degrees from each other. (Item 92) Item 91. The method of item 90, wherein the plurality of cycles comprises three cycles azimuthally offset by 120 degrees from each other. (Item 93) Item 91. The method of item 90, wherein the plurality of cycles comprises four cycles azimuthally offset by 90 degrees from each other. [Brief description of the drawings]

[0013] Details of the subject matter described herein, both with respect to its structure and operation, may become apparent by inspection of the accompanying figures, in which like reference numerals refer to like parts. The components in the figures are not necessarily to scale, emphasis instead being placed on illustrating the principles of the subject matter. Also, all illustrations are intended to convey concepts, and relative sizes, shapes, and other detailed attributes may be illustrated diagrammatically, rather than literally or precisely.

[0014] [Figure 1A] FIG. 1A is a schematic diagram of an exemplary embodiment of a neutron beam system in accordance with the present disclosure.

[0015] [Figure 1B] FIG. 1B is a schematic diagram of an exemplary embodiment of a neutron beam system for use in boron neutron capture (BNCT).

[0016] [Figure 2A] FIG. 2A is a perspective view of an exemplary embodiment of a target.

[0017] [Figure 2B]FIG. 2B is a cross-sectional view taken along line 2B-2B of FIG. 2A.

[0018] [Figure 2C] FIG. 2C is a cross-sectional view of another exemplary embodiment of a target.

[0019] [Figure 3A] FIG. 3A is a schematic diagram of an example of a beam path forming a first pattern in accordance with the present subject matter.

[0020] [Figure 3B] 3B-3C are schematic diagrams of example beam paths with elliptical and circular beam cross-sectional profiles, respectively. [Figure 3C] 3B-3C are schematic diagrams of example beam paths with elliptical and circular beam cross-sectional profiles, respectively.

[0021] [Figure 4A] 4A-4G are example embodiments of scan profiles having multiple instances of beam patterns repeated at different radial orientations. [Figure 4B] 4A-4G are example embodiments of scan profiles having multiple instances of beam patterns repeated at different radial orientations. [Figure 4C] 4A-4G are example embodiments of scan profiles having multiple instances of beam patterns repeated at different radial orientations. [Figure 4D] 4A-4G are example embodiments of scan profiles having multiple instances of beam patterns repeated at different radial orientations. [Figure 4E] 4A-4G are example embodiments of scan profiles having multiple instances of beam patterns repeated at different radial orientations. [Figure 4F]4A-4G are example embodiments of scan profiles having multiple instances of beam patterns repeated at different radial orientations. [Figure 4G] 4A-4G are example embodiments of scan profiles having multiple instances of beam patterns repeated at different radial orientations.

[0022] [Figure 5A] 5A and 5B are examples of computer models including targets according to the present disclosure. [Figure 5B] 5A and 5B are examples of computer models including targets according to the present disclosure.

[0023] [Figure 6A] 6A-6D are examples of modeled thermal maps according to the present disclosure. [Figure 6B] 6A-6D are examples of modeled thermal maps according to the present disclosure. [Figure 6C] 6A-6D are examples of modeled thermal maps according to the present disclosure. [Figure 6D] 6A-6D are examples of modeled thermal maps according to the present disclosure.

[0024] [Figure 7A] 7A-7F are examples of immediate path avoidance (RPA) patterns. [Figure 7B] 7A-7F are examples of immediate path avoidance (RPA) patterns. [Figure 7C] 7A-7F are examples of immediate path avoidance (RPA) patterns. [Figure 7D] 7A-7F are examples of immediate path avoidance (RPA) patterns. [Figure 7E] 7A-7F are examples of immediate path avoidance (RPA) patterns. [Figure 7F] 7A-7F are examples of immediate path avoidance (RPA) patterns.

[0025] [Figure 8A] 8A and 8B are examples of simulated boundary temperature and usage maps. [Figure 8B] 8A and 8B are examples of simulated boundary temperature and usage maps.

[0026] [Figure 9A] 9A-9J are examples of simulation results according to implementations of the present disclosure. [Figure 9B] 9A-9J are examples of simulation results according to implementations of the present disclosure. [Figure 9C] 9A-9J are examples of simulation results according to implementations of the present disclosure. [Figure 9D] 9A-9J are examples of simulation results according to implementations of the present disclosure. [Figure 9E] 9A-9J are examples of simulation results according to implementations of the present disclosure. [Figure 9F] 9A-9J are examples of simulation results according to implementations of the present disclosure. [Figure 9G] 9A-9J are examples of simulation results according to implementations of the present disclosure. [Figure 9H] 9A-9J are examples of simulation results according to implementations of the present disclosure. [Figure 9I] 9A-9J are examples of simulation results according to implementations of the present disclosure. [Figure 9J] 9A-9J are examples of simulation results according to implementations of the present disclosure.

[0027] [Figure 10] FIG. 10 is a flowchart depicting an example process that may be performed according to implementations of the present disclosure.

[0028] [Figure 11]FIG. 11 is an example system that may be implemented in accordance with the present disclosure.

[0029] [Figure 12] FIG. 12 is a schematic diagram of an exemplary computer system that can be used to carry out implementations of the present disclosure.

[0030] Like reference symbols in the various drawings indicate like elements. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] Detailed Description Before the present subject matter is described in detail, it is to be understood that this disclosure is not limited to particular embodiments described, which may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, as the scope of the present disclosure will be limited only by the appended claims.

[0032] The term "particle" is used broadly herein, and unless otherwise limited, may be used to describe an electron, a proton (or an H+ ion), or a neutron, as well as species having more than one electron, proton, and / or neutron (e.g., other ions, atoms, and molecules).

[0033] Exemplary embodiments of systems, devices, and methods for beam path of a beam along a target surface for use in or in combination with a beam system (e.g., including a particle accelerator) are described herein. The embodiments described herein can be used in conjunction with any type of particle accelerator or in any particle accelerator application involving the generation of a charged particle beam at a defined energy for feeding into a particle accelerator. The embodiments herein can be used in numerous applications, an example of which is as a neutron beam system for the generation of a neutron beam for use in boron neutron capture therapy (BNCT). BNCT uses a beam of epithermal neutrons (e.g., with an energy spectrum within 3-30 kiloelectron volts) for cancer treatment. In some implementations, the epithermal neutrons (e.g., epithermal neutron beam) are generated based on a nuclear reaction between protons (e.g., a proton beam) and either a beryllium target or a lithium target.

[0034] The proton beam can be generated by a particle accelerator such as a tandem accelerator. For example, the tandem accelerator can be an electrostatic accelerator employing two-stage acceleration of charged particles using a single high-voltage terminal. A high voltage can be used to generate an electric field that is applied to an incoming beam of negatively charged ions, accelerating them towards the center of the accelerator. The center of the tandem accelerator can be configured to convert the beam of negatively charged ions into a proton beam in a process of charge exchange. The parameters of the proton beam, such as beam dimensions, beam shape, and beam structure, can be varied to optimize target usage for localized heating of the target.

[0035] For ease of explanation, many of the embodiments described herein will be done so in the context of scanning a proton beam across a target to generate a neutron beam for use in BNCT, however the embodiments are not so limited and can be applied to scanning other charged particle beams, generating beams other than neutron beams, and for uses other than BNCT applications. The target can be maintained in a fixed (unchanging) position while scanning the proton beam across the target surface. Alternatively, the target can be moved (e.g., rotated) while the proton beam is scanned across the target surface. Both approaches are described herein. The embodiments relating to scanning (rastering) a charged particle beam are primarily described in the context of a fixed target, however, all such embodiments can be configured for use in approaches in which the target moves.

[0036] FIG. 1A illustrates a schematic diagram of an exemplary embodiment of a system 100 for use in BNCT according to the present disclosure. The system 100 includes a beam system 102 configured to generate a proton beam 104 and a target 196 scanned by the proton beam 104 to generate a neutron beam 106 directed toward a patient 108. The beam system 102 includes a charged particle source 122, a low energy beam line (LEBL) 190, an accelerator 140, and a high energy beam line (HEBL) 150. The accelerator 140 is coupled to the low energy beam line (LEBL) 190 and configured to accelerate a charged particle (proton) beam. The high energy beam line (HEBL) 150 extends from the accelerator 140 to a target assembly 110 that stores a target 196 onto which the charged particle beam can be directed. The LEBL 190 is configured to transport the beam from the source 122 to the accelerator 140. The accelerator 140 is configured to accelerate the beam. The HEBL 150 transports the beam 104 from the output of the accelerator 140 to a target 196. In some implementations, the HEBL 150 transports the beam 104 to the target 196 through a target chamber of the target assembly 110. The beam 104 can be a negatively charged particle beam or a positively charged particle beam. The target 196 can be a device that converts the charged particle beam 104 into another type of particle beam 106, such as a neutron beam, or can be a workpiece or other body onto which the charged particle beam is directed for a useful purpose, such as an irradiation target of a patient 108.

[0037] 1B is a schematic diagram illustrating an exemplary embodiment of a beam system 102 configured as a neutron beam system for use in BNCT. The beam system 102 includes a preaccelerator system 120 forming at least a portion of a LEBL, where the preaccelerator system 120 serves as a charged particle beam injector, as described with reference to FIG. 1A, a high voltage (HV) tandem accelerator 140 coupled to the preaccelerator system 120, and a high energy beamline 150 extending from the HV tandem accelerator 140 to a neutron target assembly 110 housing a neutron generating target 196. The beam system 102 as well as the preaccelerator system 120 can also be used for other applications, such as cargo inspection and applications, and are not limited to BNCT.

[0038] The preaccelerator system 120 (also referred to herein as a charged particle beam injector or ion beam injector) can be configured to transport an ion beam from an ion source 122 to an input (e.g., an input aperture) of the HV tandem accelerator 140. The preaccelerator system 120 can include an ion source 122 (e.g., a negative ion source), a turbomolecular pump 124 (e.g., an ion source vacuum chamber for removing gas), a preaccelerating tube 126, and a pump chamber 128. In some implementations, the beam source 122 can include a negative ion source. The preaccelerator system 120 can be configured to provide acceleration of the beam particles to an energy level required for the HV tandem accelerator 140 and provide an overall focusing of the negative ion beam to match the input aperture area at the input aperture or entrance of the HV tandem accelerator 140. The preaccelerator system 120 can be configured to minimize or out-focus the backflow as it passes from the HV tandem accelerator 140 through the preaccelerator system 120 to reduce the possibility of damage to the ion source 122 and / or the backflow reaching the filament of the ion source 122.

[0039] The HV tandem accelerator 140 is powered by a high voltage power supply 142 coupled thereto. The HV tandem accelerator 140 includes a vacuum tank, a charge exchange target, acceleration electrodes, and a high voltage feedthrough. The HV tandem accelerator 140, in some implementations, can accelerate a hydrogen beam to generate a proton beam with an energy generally equal to twice the voltage applied to the acceleration electrodes located within the HV tandem accelerator 140. The energy level of the proton beam can be achieved by accelerating a beam of negative hydrogen ions from the input of the HV tandem accelerator 140 to the innermost high potential electrode, stripping two electrons from each ion, and then accelerating the resulting protons downstream through the same voltages encountered in reverse order.

[0040] The high energy beamline 150 can transport the proton beam from the output of the HV tandem accelerator 140 to a neutron generating target 196 in the neutron target assembly 110, which is positioned at the end of a beamline branch 170 that extends into the patient treatment room.

[0041] The beam system 102 can be configured to direct the proton beam to one or more targets 196 and associated treatment areas. In some implementations, the high energy beamline 150 includes multiple (e.g., three) branches 170, 180, and 190 configured to extend to multiple different patient treatment rooms. The branches 180 and 190 can contain target assemblies similar to the branch 170. The high energy beamline 150 includes a pumping chamber 151, quadrupole magnets 152 and 172 to prevent out-focusing of the beam, dipole or bending magnets 156 and 158 to steer the beam toward one or more targets, a beam corrector 153, diagnostics such as current monitors 154 and 176, a high speed beam position monitor 155 section, and a scanning magnet 174.

[0042] The beam system 102 may employ one or more control systems 1101 with which one or more computing devices 1102 may communicate to interact with systems and components of the beam system 102 (e.g., neutron beam system 102). In some implementations, the computing device 1102 is configured to execute a computational model that allows for selection of a raster profile, as described with reference to FIGS. 5A and 5B. The computing device 1102 is configured to receive user input including selection of one or more parameters of a target scanning process. The parameters may define a raster profile including a beam path, an orientation of a shaped beam relative to a scannable surface of the target, a beam cross-sectional profile, and a beam velocity. The parameters may define target characteristics such as the rotation of the target 196 (e.g., angular velocity of the target). A raster path as used herein does not imply any particular beam path (e.g., moving only in orthogonal directions, etc.). In some implementations, the computing device 1102 is configured to receive real-time signals measured by the sensor 121 or thermal camera 123, which are used to adjust the raster profile in real-time using an adaptive scanning program to avoid local overheating of the target 196 (e.g., to keep the local temperature below the lithium melting temperature of 180° C.). One or more thermal sensors 121 can detect a local temperature corresponding to a portion of the target. The thermal camera 123 can be configured to generate a signal that can be processed to generate a temperature map of the target 196. The computing device 1102 can be configured to process the received inputs and generate a set of scanning parameters that are transmitted to one or more control systems 1101 to control the target scanning process.

[0043] The design of the high energy beam line 150 depends on the configuration of the treatment facility (e.g., one-storey treatment facility, two-storey treatment facility, and the like). The beam can be delivered to the target assembly 110 (e.g., located near the treatment room with the patient 108) using the bending magnet 156. A quadrupole magnet 172 can then be included to focus the beam to a size at the target. The beam can pass through one or more scanning magnets 174, which provide lateral movement of the beam on the target surface in a desired pattern (e.g., spiral, curved, stepped in rows and columns, combinations thereof, and others). The beam lateral movement allows the generation of a smooth and uniform time-averaged distribution of the proton beam on the target 196, prevents overheating of the target 196, and allows particle (e.g., neutron) generation to be as uniform as possible within the target layer 201 (e.g., lithium layer).

[0044] The scanning magnet 174 can be configured to direct the beam to a current monitor 176, which measures the beam current. The beam current value, measured by the current monitor 176, can be used to operate a safety interlock. The target assembly 110 can be physically isolated from the high energy beamline volume using a gate valve 177. The function of the gate valve 177 is to separate the vacuum volume of the beamline from the target 196 during target exchange / loading. In some implementations, instead of being bent 90 degrees by the bending magnet 156, the beam can be directed straight to the right and enter the quadrupole magnet 152, located in the horizontal beamline. The beam can be bent by another bending magnet 158 ​​to a pre-set angle depending on the setup requirements (e.g., patient location or room configuration). In some implementations, the bending magnet 158 ​​can be arranged at a branch point in the beamline and configured to direct the beam in one of two directions for two different treatment rooms located on the same floor of a medical facility.

[0045] FIG. 2A is a perspective view of the target 196, and FIG. 2B is a cross-sectional view of the target 196 illustrating the cooling channels. In this embodiment, the target 196 is disk-shaped with a generally circular outer profile. The target 196 generally includes one or more target layers 201 supported by a substrate 203. A side of the substrate 203 includes channels 204 for a coolant. A scannable surface 210 is present on the target layer 201, which is a surface of the target layer 201 that can be scanned by a proton beam to generate neutrons. The target layer 201 includes a neutron source layer, such as a layer of lithium, beryllium, or other suitable material that interacts with the proton beam 104 to generate a neutron flux. The thickness and composition of the one or more target layers 201 can vary depending on the nature of the proton beam and the desired neutron flux. For example, a lithium-based target layer can have a thickness in the range of about 10 microns (μm) to about 400 μm. The target layer 201 can be attached to the substrate 203 via a thermal bond.

[0046] The substrate 203 may include one or more layers of copper, aluminum, stainless steel, titanium, and / or molybdenum. The target layer 201, including the reactive metal, may form an amalgam with the substrate 203. The characteristics of the target 196 (e.g., layer thickness, composition, and bond type) are associated with the initiation of blistering at a particular level of particle dose per target surface.

[0047] The channels 204 can be used to circulate a coolant across the backside of the substrate 203 during operation of the system 100 to dissipate heat generated by absorption of kinetic energy from deceleration within the substrate 203 of protons that did not participate in a reaction. Alternatively, or in addition, the coolant can be provided as a fluid chamber in contact with at least a portion of the substrate 203. For example, the coolant channels can be formed as capped through-holes that traverse the substrate 203 and define closed fluid passages with a variety of different geometries (e.g., circular or rectangular cross-sections) and dimensions (e.g., cross-sectional diameters ranging from about 0.5 millimeters (mm) to about 3 mm).

[0048] The target 196 can be supported by a support structure (e.g., shaft 111 or base 112). The support structure can be configured to maintain the target 196 in a fixed position or to rotate the target 196 clockwise 114 or counterclockwise (CCW) in a vertical plane that includes a vertical axis 116 that is nominally perpendicular to the beam axis. The particle beam 104 can be dynamically directed toward the target 196 according to a particular pattern (e.g., spiral, curved, stepped in rows and columns, combinations thereof, and others) that can change over time. The pattern can be repeated at a given frequency. In some implementations, as described in detail with reference to Figures 3A-3C, 4A-4G, and 7A-7F, both the target 196 and the beam 104 move relative to the beam axis during operation such that sections of the rotatable target 196 can be contacted sequentially by the beam 104 to form a scan pattern. As a result of the interaction of beam 104 with a target layer 201 (e.g., a neutron source layer), a beam 106 (e.g., a neutron beam) is generated and directed (e.g., via a collimator or other beam shaping structure) toward a treatment area of ​​a patient 108.

[0049] 2C is a cross-sectional view of another exemplary embodiment in which a target 196 includes an intermediate layer 202 located between a target layer 201 and a target substrate 203. The intermediate layer 202 can reduce the possibility of blister formation in the target 196 due to beam impingement. The intermediate layer 202 can be made of a thermally conductive material that is resistant to blistering, such as tantalum.

[0050] During operation of the beam system 102, the proton beam 104 is directed at a scannable surface 210 of the target 196. To avoid overheating, the proton beam 104 is moved at a rapid rate in two or more directions (e.g., X and Y) across the surface 210, a process called scanning. The path the beam takes across the surface 210 determines the amount of heating that occurs at different locations across the surface 210 and the relative difference in particle load on the target 196. The beam path can be adapted to the ability of the system to cool the target 196 and the ability of the target 196 to withstand the dispersion of the particle load.

[0051] 3A is a schematic diagram depicting an example pattern 300 formed by a path 301 that a beam takes across a surface 210. The outer boundary of the beam cross section is indicated by a cross-sectional profile 320, which in this example is circular. The pattern 300 of the path 301 is curved with multiple loops or trajectories created as the beam travels from an outer region of the surface 210 to an inner region and then back to the outer region again. The beam path 301 includes a start location A and a stop location O. The locations A, O can be the same single location or different locations. In some embodiments, the start and stop locations A, O can be the same location or in close proximity to each other (e.g., adjacent locations or locations within one beam diameter of each other).

[0052] Path 301 begins at location A and proceeds in a CCW manner as indicated by arrow B. Path 301 continues in an inwardly directed spiral manner (e.g., with a continuously decreasing radius) as indicated by arrows C, D, E, F, G, and H. Arrow H indicates the entry of beam path 301 into a smaller radius trajectory until it reaches location I, marking the location where the beam path radius transitions from a continuously decreasing radius to a continuously increasing radius. In other words, at location I, beam path 301 begins to transition from the inner region back toward the outer region of surface 210. Arrow J indicates the path 301 of the beam from location I in a counterclockwise manner in an outwardly directed spiral manner (e.g., with a continuously increasing radius) as indicated by arrows K, L, M, and N, until it reaches stop location O. At this point, path 301 has completed the transition from the outer region to the inner region and back to the outer region of surface 210. A path with at least one orbit centered around a center point, having start and stop locations at the same distance (or radius) from the center point, and passing between a minimum distance (or radius) from the center point and a maximum distance (or radius) from the center point is referred to as a cycle. The start and stop locations may be at any distance between (and including) the minimum and maximum distances. In this case, a single cycle forms a closed loop such that the stop location O is substantially at or adjacent to the start location A.

[0053] The pattern 300 can cover a majority of the surface area of ​​the target scannable surface 210. In this embodiment, the beam profile 320 is large enough so that the area of ​​the surface 210 impacted by the beam will overlap as the beam transitions through each trajectory. In other words, the width of the beam profile 320 measured perpendicular to the direction of beam travel exceeds the distance between adjacent trajectories. The pattern 300 is symmetrical along the axis 330 such that the first half 332 of the pattern 300 is a mirror image of the second half 334 of the pattern 300. The outward-to-inward portion of the path 301 from location A to location I is a mirror image of the inward-to-outward portion of the path 301 from location I to location O.

[0054] Although path 301 is described as transitioning in a CCW manner, transitioning from an outer region to an inner region and back, the embodiments described herein are not so limited. For example, in some implementations, the beam may utilize a path that follows a clockwise (CW) rotation, beginning in the inner region, transitioning to the outer region, and then returning to the inner region (one cycle). Path 301 may complete an entire cycle or only a portion of a cycle, for example, involving a transition from the inner region to the outer region or vice versa.

[0055] 3B and 3C are schematic diagrams depicting examples of different paths taken with different beam cross-sectional profiles. In FIG. 3B, an elliptical (e.g., oval) beam profile 342 with an X dimension larger than the Y dimension follows a path 341 that is sized so that the beam cross-sectional profiles of adjacent tracks touch but do not overlap when aligned along the central X axis. With a fixed spacing between the tracks, the beam would leave gaps, most evident when aligned along the Y axis. To cover the entire area with a minimum level of exposure, the entire path would need to be elliptical with an aspect ratio similar to profile 342 with a total Y dimension smaller than the X dimension. FIG. 3C shows an example with a circular cross-sectional profile 352 taking a path 351. No gaps are present in FIG. 3C, but the amount of tracks is larger (slightly more than 4 compared to 3.75 in FIG. 3B).

[0056] 4A-4B are schematic diagrams depicting an exemplary embodiment of a scan (or raster) profile 400 formed by a cycle 405 scanned multiple times at different radial orientations to form a group of radially shifted instances of the cycle. In this embodiment, each instance of the cycle 405 has the same pattern and a stop location that is different from that instance's starting location of the cycle 405. FIG. 4A depicts a cycle 405 formed by beam paths 406 whose start position A and stop position O are at different locations, offset by 180 degrees in this example. The cycle 405 is rotatable or clockwise for repetition at different radial orientations to form a closed loop.

[0057] A scan profile 400 is depicted in FIG. 4B. Here, the scan profile 400 includes two instances of a cycle 405 with a 180 degree difference in radial orientation between them. The first instance of the cycle 405 is shown by path 401, which is depicted with a start location A1, a midpoint I1, and a stop location O1 in the same positions as in FIG. 4A. The second instance of the cycle 405 is shown by path 402, which has a start location A2, a midpoint I2, and a stop location O2. Path 402 has the same shape as path 401, but is rotated (or clockwise) by 180 degrees. For example, a forward clockwise rotation can be implemented by uniformly advancing the transformed theta coordinates over the cycle from A1 to O1, such that O1 ends 180 degrees away from A1. Every location on path 401 is radially offset from its same or corresponding location on the next path 402 in the sequence by the same radial amount. Locations A2, I2, and O2 are each shown 180 degrees from A1, I1, and O1, respectively. In this and other embodiments described herein, the clockwise rotation of the cycle can be performed in the CW or CCW direction.

[0058] The stop location (e.g., O1) of the first cycle is at or adjacent to the start location (e.g., A2) of the immediately following shifted cycle so that the beam can move from one instance of cycle 405 to the next in an uninterrupted manner. The start location A1 of the first cycle (e.g., path 401) and the stop location O2 of the last cycle (e.g., path 402) of the group are substantially identical or adjacent to each other. Thus, the profile formed by a group of two or more radially shifted cycles has identical (or adjacent) start and stop locations and forms a closed loop. A group of two or more cycles each having the same pattern, where each cycle has a start location and a stop location at the same distance (or radius) from the center point and each cycle is rotatable in orientation so that adjacent cycles can be linked together and form a closed loop for the group, is referred to herein as a supercycle. Scanning the target 196 may involve moving the beam through a first cycle (e.g., path 401) in a first radial orientation and then moving the beam through an identical cycle (e.g., path 402) at least one or more times, but with the subsequent cycle in a different radial orientation than that of the first cycle. This process is repeated until a supercycle is completed, at which point the process of scanning is repeated. The scanning process may be repeated continuously until the entire procedure, e.g., BNCT treatment, is completed.

[0059] The terms radial orientation, radial shift, and radial offset are used herein to describe a cycle that can be rotated (or clockwise) around a center point without changing the basic shape of the cycle as a whole. For example, in FIG. 4A, cycle 405 has a first radial orientation, shown by path 401. Cycle 405 is then radially (circumferentially) shifted by 180 degrees to a second radial orientation, shown by path 402. The radial offset between the two instances 401, 402 of cycle 405 is 180 degrees. Characterizations can be expressed similarly by substituting the term azimuth for radial (e.g., azimuth orientation, azimuth shift, and azimuth offset). For example, a theta value can define an orientation position around a central point on the scannable surface (similar to the hour hand on a clock, where an orientation at the 3 o'clock position corresponds to 90 degrees theta, an orientation at the 6 o'clock position is 180 degrees theta, an orientation at the 9 o'clock position is 270 degrees theta, etc.), and a cycle position can be expressed in reference to theta and orientation.

[0060] 4C and 4D are schematic diagrams depicting a cycle 415 that is repeated four times with a 90 degree difference in radial orientation between adjacent instances to form another embodiment of the scan profile 400. In FIG. 4C, the cycle 415 is formed by a beam path 411 that starts at location A1, proceeds in a CCW manner to a midpoint I1 in the inner region of the surface 210, and then returns to the outer region at a stop location O1. The stop location O1 is radially offset CCW from the start location A1 by 90 degrees, which is the same amount of radial offset that exists between the cycles 415 of the present profile 400. FIG. 4D depicts a second instance of the cycle 415, shown by path 412 with a start location A2, a midpoint I2, and a stop location O2. FIG. 4E is identical to FIG. 4D, except for the addition of a third instance of the cycle 415, shown by path 413 with a start location A3, a midpoint I3, and a stop location O3. Figure 4F is identical to Figure 4E, except that a fourth instance of cycle 415 is added, as shown by path 414 having start location A4, midpoint I4, and stop location O4, forming a completed supercycle of scan profile 400. When this embodiment of scan profile 400 is used, the beam is transitioned through path 411, then path 412, then path 413, then path 414, completing a supercycle that can then be repeated continuously throughout the procedure.

[0061] In the example illustrated by Fig. 4G, the scan profile 400 is a supercycle that includes three cases 421, 422, 423 that are identical but with a difference in radial orientation of 120 degrees between adjacent ones. The cycle of Fig. 4G is modified from that of Fig. 4A to allow three iterations with one closed loop. The second case 422 is radially shifted 120 degrees CCW from the first case 421, and the third case 423 is radially shifted 120 degrees CCW from the case 422 (radially shifted 240 degrees CCW from the case 421). Locations A2, I2, and O2 are shown at 120 degrees CCW from A1, I1, and O1, respectively, and locations A3, I3, and O3 are shown at 120 degrees CCW from A2, I2, and O5, respectively. The beam is transitioned through case 421, then case 422, then case 423, completing the supercycle, which can be repeated multiple times consecutively throughout the procedure.

[0062] Additional exemplary embodiments of the scan profile 400 may also be implemented. The amount of radial offset between the repeated patterns 301 may be determined by dividing 360 degrees by the number of pattern instances. For example, a profile 400 having five instances of cycles may have a radial offset of 72 degrees between adjacent cycles, a profile 400 having six instances of cycles may have a radial offset of 60 degrees between adjacent cycles, a profile 400 having seven instances of cycles may have a radial offset of approximately 51.4 degrees between adjacent cycles, a profile 400 having eight instances of cycles may have a radial offset of 45 degrees between adjacent cycles, a profile 400 having nine instances of cycles may have a radial offset of 40 degrees between adjacent cycles, a profile 400 having ten instances of cycles may have a radial offset of 36 degrees between adjacent cycles, a profile 400 having eleven instances of cycles may have a radial offset of approximately 32.7 degrees between adjacent cycles, a profile 400 having twelve instances of cycles may have a radial offset of 30 degrees between adjacent cycles, and so on.

[0063] In some implementations, the stopping location of the first instance of the cycle may not be identical to, or even close to, the starting location of the next instance of the cycle. For example, the beam may fill the gap in a relatively rapid manner that has a negligible effect on overall thermal performance and particle loading. If the beam is pulsed, the radial shift may occur between pulses while the beam is off.

[0064] Although the embodiments described herein are shown with identical cycles repeated multiple times within a supercycle, it should be noted that the cycle patterns need not be the same, differing only in radial orientation. In practice, slight variations will inherently exist given tolerances within the system and variances in operating conditions between procedures. Indeed, the scope of the present subject matter encompasses embodiments in which the repeated cycle patterns are not the same, but rather are substantially the same, with differences caused by tolerances, operating condition variances, and even programmed or otherwise intended non-identities in the patterns.

[0065] In general, the thermal effects of the beam on the target can be computationally investigated using computational models. Computational modeling can enable the selection of a beam raster profile that improves the uniformity of the particle load on the target and / or can enable the selection of a raster profile that reduces (e.g., minimizes) the peak transient temperature of the target. The raster profile can be characterized by the beam path and beam profile (e.g., circular or elliptical beam with specific dimensions) as described with reference to Figures 8 and 9. In some implementations, the raster profile can define the beam scanning speed.

[0066] The computational model can allow for the investigation of the effect on the target of one or more of a variety of beam parameters, such as the size and shape of the beam. Additionally, the thermal effects of the beam can be calculated by calculating one or more figures of merit (e.g., peak temperature, temperature change, average temperature), and applying numerical analysis to the figures of merit can allow the computational model to be used to optimize the raster profile of the beam.

[0067] In general, the computational model may involve generating a mesh-like space that encompasses the target. The computational model is illustrated in Figures 5A and 5B, which illustrate a mesh consisting of a three-dimensional grid in which the heating (temperature map) of the target 196 may be modeled. Temperature values ​​are modeled by solving a one-dimensional heat transport equation at each "pixel" (e.g., each xy square of the grid shown in 5A). The one-dimensional heat transport equation (u t =c 2 u xx , which defines the temperature at the pixel using a constant c as the thermal diffusivity, is solved for heat transport through the pixel's depth in the Z direction, as shown in FIG. 5B. Crosstalk between pixels or lateral heat conduction between pixels is assumed to be negligible, so heat only travels horizontally in the Z direction, allowing a 1D approach to be used. The beam is considered to generate a propagation of heat over a certain depth into each pixel corresponding to the incident beam (e.g., about 25% of the beam energy is deposited uniformly through the lithium layer, and the remaining energy is deposited in the copper first element). Compositional changes are considered through the pixel's depth. Any suitable computational approach to solving the one-dimensional heat transport differential equation can be used. For example, numerical approaches can include finite element and finite difference approaches. For either the finite element and finite difference techniques, the target 196 can be represented in a plan view 220 as part of a grid 226 (as illustrated in FIG. 5A). The size of the grid can vary and can be selected based on the size of the target, the beam size, and the desired computational efficiency and result accuracy. Generally, smaller sizes give more accurate answers, but may be computationally expensive. In the current embodiment shown in FIG. 5A, the grid 226 includes 36×36 pixels (cells), but generally the number of pixels may be in the range 10 3 ~10 5 It may be within or even beyond.

[0068] In general, the grid can have the same unit cell size in each dimension, or the size in each dimension can vary. The resolution can be selected to provide the ability to model beams of different sizes and structures, consistent with the physical capabilities of the system under study.

[0069] 5B is an example of a model of a target side view 230 of the target 196 illustrated in FIG. 2A. The model of the target side view 220 includes multiple layers, which may correspond to layers 201, 202, 203, described with reference to FIGS. 1B and 2C. In some implementations, the layers may have thicknesses defined by pixels of a numerical grid 226. In some implementations, the boundaries of the target layer 201 are modeled as corresponding to a vacuum, and the boundaries of the target substrate 203 are modeled as corresponding to a coolant fluid (e.g., water), defining boundary conditions for a one-dimensional heat transport equation.

[0070] 6A-6D show examples of simulated thermal maps using the model described with reference to FIG. 5A and 5B. FIG. 6A and 6B show examples of simulated thermal maps 610, 620 determined using the computational model as described above for beam sizes of 10 mm and 20 mm, respectively. FIG. 6C and 6D show examples of simulated thermal maps 630, 640 determined using ANSYS® engineering simulation software for beam sizes of 10 mm and 20 mm, respectively. The model used to generate the simulated thermal maps 610, 620 is based on a transient code that tracks surface particle loading based on any given beam profile combined with any raster profile. The model was benchmarked against a transient model calculated using the 3D heat transfer code ANSYS® as validation.

[0071] The overall profiles of the simulated thermal maps 610, 620, 630, 640, calculated based on the assumption of a scanning frequency of 120 Hz, generally match for both the 10 mm and 20 mm beam sizes. For example, both Figures 6A and 6C show a surface temperature distribution with a characteristic thermal maximum corresponding to the center of the 10 mm proton beam. The highest average lithium surface temperature was 284°C as determined by the model and 299°C as determined by the ANSYS® model. The temperature drop from the center of the 10 mm proton beam to the edge of the 10 mm proton beam was found to be 162.7°C as determined by the model and 177.7°C as determined by the ANSYS® model. Both Figures 6B and 6D show a dispersed surface temperature distribution corresponding to the 20 mm proton beam. The highest average lithium surface temperature was 177°C as determined by the model and 184°C as determined by the ANSYS® model. The temperature drop from the center of the 20 mm proton beam to the edge of the 20 mm proton beam was found to be 55.7° C. as determined by the model and 63.3° C. as determined by the ANSYS® model. The fact that some of the calculated temperature values ​​are above the acceptable limits for lithium does not detract from the validity of the model.

[0072] Table 1 shows the predicted temperature variation (ΔT) and peak temperature (T) as determined using the model described with reference to Figures 5A and 5B and using ANSYS® engineering simulation software. max ) and the model was analyzed to determine the correlation between the modeled values ​​with respect to values ​​determined using computationally expensive ANSYS® engineering simulation software to determine the reliability of the model developed. The reliability of the model is reflected by the difference in the thermal results. A temperature rise difference of approximately 10% was found between the two sets of results, indicating agreement between the model and the transient ANSYS® model. [Table 1]

[0073] As is evident from the raster patterns shown in Figures 3A-5G, there are numerous points in each pattern where the beam path crosses itself. Each crossing point is a location where the target surface is exposed to a significantly higher particle flux (e.g., twice as much) than where the target surface is exposed only once per supercycle. If the time between successive passes across the crossing point is relatively long and the heat from the first pass can be sufficiently dissipated before the second exposure, the increased dose associated with the second exposure may not result in excessive heating at the crossing point. However, if the crossing points are exposed twice in a relatively short period, these crossing points may be locations of unacceptably high heat load. Thus, in some implementations, the computational model described above can be used to reduce the heat load on the target by determining a path that reduces the number of crossing points that undergo multiple passes of the beam in rapid succession.

[0074] For example, a computational model can be used to vary parameters of a raster profile to avoid crossing the most recently traversed beam path within a threshold time period below which excessive heating of the target location may occur. Figures 7A-7F are schematic diagrams depicting examples of raster patterns that are useful in demonstrating such a Near Path Avoidance (RPA) strategy. In some implementations, the RPA pattern can be determined based on an iterative process. The iterative process can begin with a trochoid shape, defined as the (x(t), y(t)) positions over a given time (t). For radii r1, r2 and frequencies ω1, ω2, the basic trochoid follows the following equation over time t: x(t)=r1cos(ω1·t)+r2cos(ω2·t) y(t)=r1sin(ω1·t)+r2sin(ω2·t)

[0075] outer radius r max and the inner radius r minFor an L-lobed trochoid with r1=-(r max +r min ) / 2 r2=(r max -r min ) / 2 ω1=L+1 ω2=1

[0076] The maximum radius value r is substantially equal to the beam width max and a minimum radius value r substantially equal to half the beam width. min A radius with r can provide good results for a beam of uniform intensity. max and r min The optimal value for can be found through optimization algorithms and thermal simulation codes.

[0077] Setting t to be the time dictates the speed at which the raster moves, which can be varied based on the steering magnets' capabilities and the target burnout risk. For example, a high raster speed may exceed the steering magnets' capabilities, or a low raster speed may lead to target burnout (if exposed too long to a particular radiation dose). For every modified trochoidal raster profile, the next beam position is calculated such that the speed remains approximately constant. Varying the speed based on the beam position can provide another avenue for improvement. The optimal speed profile can be found by training a machine learning algorithm on the results generated by the thermal simulation code, as described with reference to Figures 8A, 8B, 9A, and 9B.

[0078] A trochoidal pattern with constant speed can give good results in target usage, but can lead to overheating. For example, a trochoidal pattern moves to the center of the target quite frequently because the trochoidal path follows each lobe consecutively. To solve the heating problem, the raster pattern can be modified so that instead of following the path along each lobe consecutively, a ω=(L-1)th lobe order is used. Moving to the lobes in this order gives the center additional time to cool between lobes. This is where the name Nearest Path Avoidance (RPA) raster comes from, since the most recently traveled path is avoided, extending the time it takes the beam to traverse the most recent path. For some values ​​of L, it may be optimal to take a lobe more frequently than every ω=(L-1)th lobe. Any lobe frequency ω that is relatively prime to the total number of lobes L can work depending on the physical parameters of the system (beam profile, target shape, target material, etc.). The selection of the lobe frequency ω can be optimized through computational techniques, such as using machine learning algorithms.

[0079] In some implementations, the raster path follows every (L-1)th lobe, otherwise r max Include modifications of r1 and r2 to create a filter that only allows values ​​to be traced and the center of the target time to be cooled.

[0080] For example, the initial RPA raster (RPA1) may include the following radii and frequencies: [ka]

[0081] The exponent E can be greater than 10 and less than 1,000 (10 < E < 1,000). The exact value of the exponent E can depend on multiple factors. For example, E can be set large enough to provide a well - defined window for the filter in order to avoid causing the raster to oscillate around the periphery and allowing the target to escape the beam. E needs to be set less than a threshold that would make the lobes overly narrow and define a window that would overheat the target. In some implementations, E can be set such that E = 100·(L - 3), where L is greater than or equal to 4 and less than or equal to 8 (4 ≤ L ≤ 8).

[0082] RPA1 functions well to minimize heating but can leave unused regions of the target. RPA1 can be used to develop RPA2, which adds another term to r1 and defines another set of L lobes that can fill the unused regions. RPA2 uses the following radii and frequencies.

Chemical formula

[0083] The coefficient r is greater than r min and can be less than the difference between the radius limit r max and r min (r min < r < r max - r min ). The exponent E can be greater than 100 and less than 10,000. The exact values of the coefficient r and the exponent E can be optimized using thermal simulation and optimization algorithms. In some implementations, one or more additional rasters (RPA - N) can be determined by adding terms to r1, and each new term can be optimized to minimize target heating and target usage variation.

[0084] FIG. 7A illustrates an example of a trochoidal raster pattern 700 that can be generated by directing a beam toward a target (static or rotating). The trochoidal raster pattern 700 can be used as an initial raster pattern for an iterative process, as described with reference to FIG. 10. The trochoidal raster pattern 700 can include multiple lobes 702, 704, 706, 708 (e.g., four lobes as illustrated in FIG. 7A). In some implementations, values ​​for the inner radius 701 and the outer radius 703 can be found through an optimization algorithm and by using the thermal simulation code described above with reference to FIGS. 5A and 5B. The trochoid raster pattern 700 includes a number of beam crossing points 705a, 705b, 705c, 705d, 705e, 705f, 705g, 705h, 705i, 705j, 705k, 705l, 705m, 705n, where the beam path crosses itself. For example, considering the starting point 705 of the trochoid raster pattern 700, the first beam crossing point is 705a, the second beam crossing point is 705b, the third beam crossing point is 705c, the fourth crossing point is 705d, and the fifth crossing point is 705e.

[0085] 7B illustrates an example of a modified raster pattern 710 in which the order of lobes 702, 708, 706, 704 is modified to extend the cooling period at the point where the beam path crosses itself, generating a Near Path Avoidance (RPA) pattern. The duration between subsequent beam crossings is directly proportional to the arc length traversed by the beam during each successive crossing. For example, considering the start point 705 of the modified raster pattern 710, the first crossing point is 705g, which is associated with a longer arc length than the arc length corresponding to the first crossing point 705a of the trochoidal raster pattern 700.

[0086] In some implementations, the RPA pattern can be further modified to fill unused areas of the target, as described with reference to Figures 7C-7F.

[0087] 7C-7F are schematic diagrams depicting an example of a near path avoidance (RPA) pattern 720 that is repeated multiple times (e.g., four times) to form a complete supercycle of a scan profile. FIG. 7C illustrates a first cycle 722 of the RPA pattern. The first cycle 722 of the RPA pattern 720, which starts at 722A and stops at 722O, includes multiple beam crossing points 725a, 725b, 725c, 725d where the beam path crosses itself. For example, considering the starting point 722A of the first cycle 722 of the RPA pattern 720, the first beam crossing point is 725a, the second beam crossing point is 725b, the third beam crossing point is 725c, and the fourth crossing point is 725d.

[0088] 7D illustrates a second cycle 724 of the RPA pattern 720 that may be performed after completion of the first cycle of the RPA pattern. The second cycle 724 of the RPA pattern 720, which begins at 724A and stops at 724O, includes multiple beam crossing points 735a, 735b, 735c, 735d, where the beam path crosses itself. For example, considering the starting point 724A of the second cycle 724 of the RPA pattern 720, the first beam crossing point is 735a, the second beam crossing point is 735b, the third beam crossing point is 735c, and the fourth beam crossing point is 735d.

[0089] 7E illustrates the first two cycles 726 of the RPA pattern 720. The first two cycles 726 of the RPA pattern 720 include beam crossings 725a, 725b, 725c, 725d of the first cycle 722, beam crossings 735a, 735b, 735c, 735d of the second cycle 724, and beam crossings 745a, 745b, 745c, 745d, 745e, 745f, 745g, 745h, 745i, 745j, 745k, 745l, 745m where the path of the second cycle 724 crosses the path of the first cycle 722.

[0090] 7F illustrates a complete supercycle 728 of the RPA pattern 720. The complete supercycle 728 of the RPA pattern 720 includes beam crossings for each cycle (e.g., beam crossings 725a, 725b, 725c, 725d of the first cycle 722, beam crossings 735a, 735b, 735c, 735d of the second cycle 724) and beam crossings where the path of one cycle crosses the path of another cycle.

[0091] Each cycle of the RPA pattern 720 includes a stop position 722O, 724O that is a distance from the start position of the corresponding cycle 722A, 724A. The stop position of a cycle (e.g., the stop position 722O of the first cycle) corresponds to the start position of the subsequent cycle (e.g., the start position 724A of the second cycle). As illustrated in FIG. 7F, the RPA pattern 720 is formed by a beam path 728 that starts at a location 722A, travels in a CCW manner along four cycles (including the first two cycles 726 illustrated in FIG. 7E), and then returns to the start position 722A. The exemplary RPA pattern 720 illustrated in FIG. 7F forms a raster profile with four cycles that form a closed pattern based on a single complete supercycle, closing the loop.

[0092] 8A and 8B show examples of a simulated boundary temperature map 802 and a simulated target usage map 804 corresponding to a target scan using the RPA pattern described with reference to FIG. 7B for a continuous path following the RPA pattern with a constant speed. The boundary temperature map 802 defines the boundary between the lithium and copper layers of the target taking into account a neutron model that identifies the boundary as the highest energy deposition layer with the hottest measured or modeled temperature. The target usage map 804 shows the amount of lithium consumed by each portion (pixel) of the target in response to irradiation with a proton beam directed toward the target using the RPA pattern.

[0093] The simulated boundary temperature map 802 as illustrated by Fig. 8A contains circularly distributed thermal maxima corresponding to the most used cells as illustrated by the simulated target usage map 804 of Fig. 8B. The highest peak temperature in the simulated boundary temperature map 802 was less than 150°C. The temperature variation across the target surface in the simulated boundary temperature map 802 was about 40°C. The simulated boundary temperature map 802 and the simulated target usage map 804 show that scanning the target using an RPA pattern is effective in preventing target damage through blisters or bubbles.

[0094] Additive modeling using the transient code provides several figures of merit for evaluating target performance. The figures of merit include peak temperature, temperature change, average temperature, utilization efficiency, nominal frequency, and beam shape. Peak temperature includes the maximum temperature found on the target at any time. Temperature change includes the maximum temperature found on the target at any time minus the initial target temperature. Average temperature is the average of the temperatures of all cells in the target. Utilization efficiency includes the total target beam flux divided by the utilization of the maximally utilized cells normalized to the total number of cells in the target. Results of modeling using the transient code to evaluate target performance in response to one supercycle or multiple (e.g., four) repeated supercycles are included in Table 2. [Table 2-1] [Table 2-2]

[0095] 9A-9J show examples of simulation results for multiple beam profiles to compare target heating and target usage. Each simulation uses a raster pattern 300 to highlight the variations caused by the different beam profiles themselves. FIGS. 9A and 9B show simulated heat map 902 and simulated usage map 904, respectively, for a 20 mm circular (solid) beam with a frequency of 120 Hz. FIGS. 9C and 9D show simulated heat map 906 and simulated usage map 908, respectively, for a 10 mm circular (solid) beam with a frequency of 120 Hz. FIGS. 9E and 9F show simulated heat map 910 and simulated usage map 912, respectively, for a 15 mm×25 mm elliptical (solid) beam with a frequency of 120 Hz. Figures 9G and 9H show simulated heat map 914 and simulated usage map 916, respectively, for a 20 mm annular (hollow) beam with a 10 mm hole, having a frequency of 120 Hz. Figures 91 and 9G show simulated heat map 918 and simulated usage map 920, respectively, for a 10 mm circular (solid) beam with a frequency of 240 Hz.

[0096] Table 3 shows the relationship between the percentage of usage and the peak temperature (T max9A and 9B show simulation results for multiple beam profiles and raster patterns that allow comparison between the 20 mm beam and the 10 mm beam. The data was generally analyzed to determine the optimal beam profile and raster pattern. For example, the simulation results as illustrated in FIGS. 9A and 9C showed that the 20 mm beam exhibited an overall uniform temperature distribution. The simulation results as illustrated in FIGS. 9B and 9D showed that the 10 mm beam exhibited more uniform usage, especially near the edges. The simulated thermal map 910 and usage map 912 corresponding to the elliptical beam as illustrated in FIGS. 9E and 9F, respectively, show increased coverage along the orientation of the major axis of the elliptical beam. Comparing the results of the simulation as illustrated in FIGS. 9E and 9F with the results of the simulation as illustrated in FIGS. 9A and 9B shows that the elliptical shaped beam with nearly the same area as the circular beam produces a less uniform temperature and usage distribution than the circular beam. Simulated thermal maps 914 and usage maps 916, corresponding to annular beams as illustrated in Figures 9G and 9H, respectively, show reduced peripheral coverage with non-uniform radial distribution. Comparing the results of simulations as illustrated in Figures 9G and 9H with those of simulations as illustrated in Figures 9A and 9B, shows that using any type of beam with holes reduces efficiency and produces a more non-uniform temperature distribution throughout the target. Comparing the results of simulations as illustrated in Figures 9I and 9J with those of simulations as illustrated in Figures 9A and 9B, shows that using a 240 Hz beam produces a more uniform temperature distribution throughout the target and similar target usage. [Table 3]

[0097] FIG. 10 is a flow chart depicting an exemplary process 1000 that may be performed according to implementations of the present disclosure. Various possible raster profiles for scanning a proton beam across a target are established (1002) using a computer processing system. Each raster profile defines a different scan pattern of the target. Each scan pattern includes multiple supercycles that form a closed path on the target surface based on one or more cycles, closing a loop. The scan pattern may include an RPA pattern (e.g., a trochoidal shape including multiple lobes) as described with reference to FIGS. 7A-7D or other scan patterns described above. The scan pattern may be characterized by one or more path parameters. In some implementations, the parameters include one or more of the following parameters: an angular frequency associated with each lobe of the path of the proton beam, a linear velocity of the proton beam across the surface of the target, a number of radial scan layers in a supercycle of the path of the proton beam, a passing order of the lobes, and a number of supercycles of the path of the proton beam. The angular frequency and angular velocity of the proton beam may vary for different lobes of the RPA pattern. The order of passage of the lobes may be forward, reverse, or disjoint. The path parameters characterize the path of the proton beam across the target. The path parameters of the selected raster profile define a path for the proton beam that has a minimum delay (more than a threshold period) between successive exposures of a single location of the target to the proton beam to minimize target damage. In some implementations, the possible raster profiles include masked profiles that may be formed based on real-time measurements based on imaging data (e.g., a thermal map of the target). The masked profiles may define a scan profile configured to avoid portions of the target, including weak areas (e.g., areas heated to near melting point) or damaged areas of the scannable area of ​​the target.

[0098] In addition to the scan pattern, each raster profile includes settings for one or more beam parameters. Each beam parameter characterizes the properties of the proton beam. The beam parameters can include one or more of the following parameters: beam dimensions (e.g., diameter for a circular beam), beam shape, and beam structure. In some implementations, the beam dimensions are in the range of 10 mm to 30 mm. The raster profile can be modified with normalization factors in the X and Y directions depending on the beam shape. The beam shape can be circular or elliptical. If the beam shape is elliptical, the scan can be modified to effectively change by lowering the scan radius in the direction where the beam is largest so that the beam does not scan outside the outer boundary. The structure of the beam refers to the beam intensity distribution across its cross section. In some implementations, the distribution can be approximately constant or Gaussian. In some implementations, the distribution can have more than one peak, such as for an annular beam structure.

[0099] One or more target parameters characterizing the target are also established using the computer processing system (1004). For example, the target parameters can include a target surface area, a target thickness, and / or a target composition.

[0100] A figure of merit value is calculated for each potential beam raster profile (1006). In general, the figure of merit is based on the heat load of the target by the proton beam for the corresponding potential raster profile. In some implementations, calculating the value for the figure of merit includes calculating, for each potential raster profile, a heat load at each of a plurality of discrete portions of the target based on a linear relationship between the heat load and the proton flux at each discrete portion for the corresponding raster profile. In some implementations, each discrete portion corresponds to an area of ​​the target's surface within the path of the proton beam that is smaller than a dimension of the proton beam. In some implementations, the heat load at each discrete portion is calculated based on heat transfer through a depth of the target away from the surface of the target on which the proton beam is incident. In some implementations, the figure of merit is selected from the group consisting of a peak temperature of the target, a temperature change of the target, an average temperature of the target, and a utilization efficiency of the target.

[0101] A raster profile is selected from among the possible raster profiles based on the value of the figure of merit and based on the measured properties of the target (1008). In some implementations, the selection of the raster profile includes presenting a list of possible raster profiles to an operator of the proton beam and receiving user input, including the operator's selection from the list, via a user interface of the computer system. In some cases, the raster profile selection can be made automatically, for example, based on measurements of either beam properties, target properties, or both. For example, if a threshold level of heating is detected on the target, the system can switch to a different raster profile that is less taxing on the location where the threshold load is detected. In some implementations, the system uses an active feedback or feedforward process to periodically adjust the raster profile to extend the useful life of the target.

[0102] In some implementations, multiple raster profiles are included in the candidate profile F k(t), and the cutover function s k (t) can be applied to switch profiles. The output profile F(t) can be defined by: [ka] where, for all values ​​t in the domain of the output profile, [ka] It is.

[0103] For example, a simple linear intersection between two profiles F1(t) and F2(t), starting at t1 and ending at t2, can be described by defining s1(t) and s2(t) as follows: [ka]

[0104] After selection of a particular raster profile, the proton beam is scanned 1010 across the target according to the selected raster profile.

[0105] One or more properties of the beam are measured (1012) as part of the process 1000. In some implementations, the properties of the beam are measured upstream from the target. Beam properties that may be measured include, for example, beam size, beam structure, and beam profile, as described with reference to Figures 9A-9J. The beam profile can be measured using an infrared camera configured to determine the beam shape at the target location.

[0106] One or more properties of the target are measured (1014) as part of the process 1000. In some implementations, the one or more properties of the target include the temperature of the target at one or more locations across the target. For example, one or more thermal sensors (e.g., infrared cameras) can detect the temperature of the target at corresponding locations. In some implementations, a temperature map of the target can be obtained by the thermal camera. The measured temperatures can be used as input to dynamically adjust or change the raster profile during the scanning process to avoid local overheating of the target. In some cases, the system can pause beam operation entirely to avoid overheating of the target and resume operation once the target has cooled to an acceptable level.

[0107] Thus, implementations of the present disclosure may include several advantages. In some examples, the described techniques provide accurate estimation of target heating and usage with minimized computational resource requirements. The designs described herein illustrate the advantages of specific raster and beam profiles that may extend the life of the target by maintaining peak temperatures below target damaging (e.g., blistering) temperatures. The described implementations may also enable improved performance of BNCT by providing a uniform distribution of particle load on the target, which positively impacts the profile of the particle beam irradiating the patient.

[0108] In one aspect...[A patent attorney would include a list of claims here once the claims are finalized]

[0109] FIG. 11 is a block diagram illustrating an example system that may be implemented according to the present disclosure. For example, the illustrated example system 1100 includes a beam system 102, one or more computing devices 1102, and one or more servers 1110. In some implementations, the beam system 102 may be part of an example neutron beam system (e.g., the system 102 described with reference to FIGS. 1A and 1B). The beam system 102 may employ one or more control systems 1101 with which the one or more computing devices 1102 may communicate to interact with systems and components of the beam system 102 (e.g., the neutron beam system 102). The control system 1101 may be programmed to control steering devices (e.g., magnets, XY shifters) in the HEBL 50 that determine the XY position of the proton beam incident on the scannable surface 210 of the target 196. The beam system 102 , the one or more computing devices 1102 , and the one or more servers 1110 are configured to communicate with each other directly or via a local network, such as network 1104 .

[0110] The control system 1101 can be programmed with amplitude and offset control parameters that allow fixed displacement of the beam to control the location of the entire scan pattern. In some embodiments, the parameters are programmed in or for a digital signal processor (DSP) that controls the magnet power supply. The amplitude and offset parameters can be input to the DPS in real time, i.e., on the fly, during operation to correct for changes in beam behavior or energy. The real time parameters can form a generalized method of active feedback for ion particle beam control.

[0111] The computing devices 1102 may be embodied by a variety of user devices, systems, computing apparatus, controllers, and the like. For example, a first computing device 1102 may be a desktop computer associated with a particular user, while another computing device 1102 may be a laptop computer associated with a particular user, and another computing device 1102 may be a mobile device (e.g., a tablet or smart device). Each computing device 1102 may be configured to communicate with the beam system 102, for example, through a user interface accessible via the computing device. For example, a user may run a desktop application on the computing device 1102, which is configured to communicate with the beam system 102.

[0112] By using the computing device 1102 and communicating with the beam system 102, a user may provide operating parameters (e.g., operating voltages and the like) for the beamline components 3005 according to embodiments described herein.

[0113] The control system 1101 may be configured to receive measurements, signals, or other data from the components 1105 of the beam system 102 and the monitoring devices 1103. For example, the control system 1101 may receive signals from one or more monitoring devices 1103 indicative of the operating conditions and / or position of a beam passing through the beam system 102. The control system 1101 may provide adjustments to inputs of one or more beamline components 1105 according to methods described herein depending on the operating conditions and / or position of a beam passing through the beam system 102. The control system 1101 may also provide information collected from any of the components of the beam system 102, including the monitoring devices 1103, to the computing device 1102, either directly or via a communication network 1104. The control system 1101 can be programmed to implement embodiments of scan profiles as described with reference to FIGS. 4, 5, and 7-10.

[0114] The communication network 1104 may include any wired or wireless communication network, including, for example, a wired or wireless local area network (LAN), a personal area network (PAN), a metropolitan area network (MAN), a wide area network (WAN), or the like, as well as any hardware, software, and / or firmware required to implement the same (e.g., network routers, etc.). For example, the communication network 1104 may include 802.11, 802.16, 802.20, and / or WiMax networks. The communication network 1104 may include a public network, such as the Internet, a private network, such as an intranet, or a combination thereof, and may utilize various currently available or later developed networking protocols, including, but not limited to, TCP / IP-based networking protocols. The computing device 1102 and the control system 1101 may be embodied by one or more computing systems, such as the system 1200 described with reference to FIG. 12.

[0115] The computing device 1102 and the control system 1101 can be configured to perform operations including scanning a beam across a scannable surface of a target along a first path and scanning a beam across a scannable surface of a target along a second path, the first path forming a first pattern in a first radial orientation and the second path forming the first pattern substantially in a second radial orientation different from the first radial orientation. The beam is pulsed while scanning along the first and second paths. The beam propagates continuously while scanning along the first and second paths. The beam moves from an inner region of the scannable surface to an outer region and back to the inner region in the first pattern. The beam moves from an outer region of the scannable surface to an inner region and back to the outer region in the first pattern. The first pattern comprises a spiral and a mirror image of the spiral. The first pattern has a first half and a second half, the first and second halves being symmetric. The first pattern is continuously curved. The first pattern has a start location and a stop location, the start location being at or adjacent to the stop location. The first radial orientation differs from the second radial orientation by 180 degrees. The operations further include scanning the beam across the scannable surface of the target along a third path, the third path forming the first pattern at a third radial orientation different from the first and second radial orientations. The first, second, and third radial orientations differ by 120 degrees. The operations further include scanning the beam across the scannable surface of the target along a fourth path, the fourth path forming the first pattern at a fourth radial orientation different from the first, second, and third radial orientations. The first, second, third, and fourth radial orientations differ by 90 degrees. The operations further include scanning the beam across the scannable surface of the target along a fifth pass, the fifth pass forming a first pattern at a fifth radial orientation different from the first, second, third, and fourth radial orientations. The first, second, third, fourth, and fifth radial orientations differ by 72 degrees.The first path corresponds to a first instance of the cycle and the second path corresponds to a second instance of the cycle. In some implementations, the scanning of the first instance of the cycle and the second instance of the cycle forms a closed loop. The beam is a proton beam. The scannable surface is a lithium or beryllium surface. The target generates neutrons when scanned. The beam has a circular cross-sectional profile. The beam has an elliptical cross-sectional profile. The beam has an annular cross-sectional profile. The beam has a hollow cross-sectional profile. The operation performs boron neutron capture therapy (BNCT). The beam is generated by a beam system comprising an ion source, a first beamline coupled to the ion source, a tandem accelerator coupled to the first beamline, a second beamline coupled to the tandem accelerator, and a target coupled to the second beamline. The pattern exposes a majority of the scannable surface to the beam. The second path forms the first pattern at a second radial orientation different from the first radial orientation.

[0116] The computing device 1102 and the control system 1101 can be configured to perform operations including scanning the beam across a scannable surface of a target along a first path, and scanning the beam across the scannable surface of the target along a second path, where the first path forms a first pattern at a first radial orientation and the second path forms a second pattern at a second radial orientation different from the first radial orientation, where the first and second patterns are substantially identical except for the different radial orientations. The first and second patterns are identical except for the different radial orientations.

[0117] The computing device 1102 and control system 1101 can be configured to perform operations including: establishing, using a computer processing system, a plurality of possible raster profiles for scanning the proton beam across a target, each of the plurality of possible raster profiles comprising one or more beam parameters, each of the one or more beam parameters characterizing a property of the proton beam and one or more path parameters characterizing a path of the proton beam across the target; establishing, using the computer processing system, one or more target parameters characterizing the target; calculating, using the computer processing system, a figure of merit value for each possible beam raster profile, the figure of merit based on a thermal load of the target by the proton beam for the corresponding possible raster profile; using the computer processing system, selecting a raster profile from among the plurality of possible raster profiles based on the value of the figure of merit; and directing the proton beam across the target according to the selected raster profile. The step of calculating a value for the figure of merit includes calculating, for each possible raster profile, a heat load in each of a plurality of discrete portions of the target based on a linear relationship between heat load and proton flux in each discrete portion for a corresponding raster profile. Each discrete portion corresponds to an area of ​​a surface of the target in a path of the proton beam that is smaller than a dimension of the proton beam. The heat load in each discrete portion is calculated based on heat transfer through a depth of the target away from a surface of the target on which the proton beam is incident. The figure of merit is selected from the group consisting of a peak temperature of the target, a temperature change of the target, an average temperature of the target, and a utilization efficiency of the target. The one or more beam parameters are selected from the group consisting of a beam dimension, a beam shape, and a beam structure. The beam dimension is in the range of 10 mm to 30 mm. The beam shape is circular or elliptical. The beam structure is circular or annular.The one or more path parameters are selected from the group consisting of a frequency associated with the path of the proton beam, a linear velocity of the proton beam across the surface of the target, a number of radial scan layers in a supercycle of the path of the proton beam, and a number of supercycles of the path of the proton beam. The one or more target parameters are selected from the group consisting of a target surface area, a target thickness, and a target composition. The target comprises a layer of lithium or a layer of beryllium. The target comprises a layer of metal supporting a layer of lithium or a layer of beryllium. The selecting step includes presenting a list of possible raster profiles to an operator of the proton beam and receiving a selection from the list by the operator via the computer system. The operations further include measuring one or more properties of the target and selecting a raster profile based on the measured properties of the target. The one or more properties of the target comprise a temperature of the target at one or more locations on the target. The operations further include measuring one or more properties of the beam and selecting a raster profile based on the measured properties of the beam. One or more properties of the beam are measured upstream from the target. The selected raster profile defines a path for the proton beam having a minimum delay between successive exposures of a single location of the target to the proton beam that exceeds a threshold period. The selected raster profile defines a path based on a trochoidal shape. The trochoidal shape comprises a plurality of lobes. An angular frequency of the proton beam varies for different lobes of the trochoidal shape. The selected raster profile comprises a range of angular velocities of the proton beam across the target surface. The selected raster profile comprises a range of linear velocities of the proton beam across the target surface.

[0118] The computing device 1102 and the control system 1101 can be configured to perform an operation including monitoring a temperature of the target while scanning the proton beam across a surface of the target according to a first raster profile, and changing the scan from the first raster profile to a second raster profile based on the monitored temperature, the second raster profile and the first raster profile resulting in a different heating profile of the target according to a computer model of the thermal loading of the target by the first and second raster profiles. The scan is changed in response to a selection of the second raster profile from among the multiple raster profiles by a human operator of the proton beam. The scan is changed automatically according to a feedback or feedforward algorithm. The temperature is monitored at multiple discrete locations of the target. The temperature is monitored by acquiring a thermal image of the target.

[0119] The computing device 1102 and the control system 1101 can be configured to perform operations including scanning a charged particle beam across a scannable surface of a target in a supercycle, the supercycle comprising a plurality of cycles, each cycle of the plurality of cycles having the same shape and a different azimuthal orientation, the plurality of cycles being linked together such that a path of the charged particle beam passes through the plurality of cycles in a closed loop. The plurality of cycles comprises two cycles azimuthally offset by 180 degrees from each other. The plurality of cycles comprises three cycles azimuthally offset by 120 degrees from each other. The plurality of cycles comprises four cycles azimuthally offset by 90 degrees from each other.

[0120] Referring now to FIG. 12, a schematic diagram of an exemplary computing system 1200 is provided. The system 1200 can be used for the operations described in connection with the implementations described herein. For example, the system 1200 may be included in any or all of the server components discussed herein. The system 1200 includes a processor 1210, a memory 1220, a storage device 1230, and an input / output device 1240. The components 1210, 1220, 1230, and 1240 are each interconnected using a system bus 1250. The processor 1210 is capable of processing instructions for execution within the system 1200. In one implementation, the processor 1210 is a single-threaded processor. In another implementation, the processor 1210 is a multi-threaded processor. The processor 1210 is capable of processing instructions stored in the memory 1220 or on the storage device 1230 and displaying graphical information for a user interface on the input / output device 1240.

[0121] The memory 1220 stores information within the system 1200. In one implementation, the memory 1220 is a computer-readable medium. In one implementation, the memory 1220 is a volatile memory unit. In another implementation, the memory 1220 is a non-volatile memory unit. The storage device 1230 is capable of providing mass storage for the system 1200. In one implementation, the storage device 1230 is a computer-readable medium. In various different implementations, the storage device 1230 may be a floppy disk device, a hard disk device, an optical disk device, or a tape device. The input / output device 1240 provides input / output operations for the system 1200. In one implementation, the input / output device 1240 includes a keyboard and / or a pointing device. In another implementation, the input / output device 1240 includes a display unit for displaying a graphical user interface.

[0122] In some implementations, two components may both utilize the use of the same processor, network interface, storage medium, or the like to perform their associated functions, such that duplicate hardware is not required for each device. Use of the terms "device" and / or "circuitry" as used herein with respect to components of the present apparatus can thus encompass specific hardware configured with software for performing the functions associated with that particular device, as described herein.

[0123] The terms "device" and / or "circuitry" should be understood broadly to include hardware, and in some embodiments, the device and / or circuitry may also include software for configuring the hardware. For example, in some embodiments, the device and / or circuitry may include processing circuitry, storage media, network interfaces, input / output devices, and the like. In some embodiments, other elements of system 1200 may provide or complement the functionality of a particular component.

[0124] In some embodiments, the processor 1210 (and / or a co-processor or any other processing circuitry that assists or is otherwise associated with the processor) may communicate with the memory 1220 via a bus to pass information between components of the device. The memory 1220 may be non-transitory and may include, for example, one or more volatile and / or non-volatile memories. In other words, for example, the memory 1220 may be an electronic storage device (e.g., a computer-readable storage medium). The memory 1220 may be configured to store information, data, content, applications, instructions, or the like to enable the system 1200 to perform various functions according to exemplary embodiments of the present disclosure, as described with reference to FIGS. 1-11.

[0125] The processor 1210 may be embodied in a number of different ways, for example, may include one or more processing devices configured to perform independently. Additionally or alternatively, the processor 1210 may include one or more processors configured to interface via a bus and enable independent execution of instructions, pipelines, and / or multi-threads. Use of the terms "processing device" and / or "processing circuitry" may be understood to include a single-core processor, a multi-core processor, multiple processors internal to the apparatus, and / or a remote or "cloud" processor.

[0126] In some implementations, the processor 1210 may be configured to execute instructions stored in the memory 1220 or otherwise accessible to the processor. Alternatively, or in addition, the processor 1210 may be configured to execute hard-coded functionality. Thus, whether configured by hardware or software methods, or by a combination of hardware and software, the processor may represent an entity (e.g., physically embodied in circuitry) that, while appropriately configured, is capable of performing operations according to certain embodiments of the present disclosure. Alternatively, as another example, when the processor 1210 is embodied as an executor of software instructions, the instructions, when executed, may specifically configure the processor 1210 to perform the algorithms and / or operations described herein. The instructions may include those necessary to determine a scanning profile and scan a target, as described with reference to FIGS. 1-11.

[0127] In some implementations, the system 1200 may include input / output devices 1260, which in turn communicate with the processor 1210 and provide output to a user and, in some embodiments, may receive input from a user. The input / output devices 1260 may include a device display, such as a user device display, which may include a user interface and may include a web user interface, a mobile application, a client device, or the like. In some embodiments, the input / output devices 1260 may also include a keyboard, a mouse, a joystick, a touch screen, a touch area, soft keys, a microphone, a speaker, or other input / output mechanisms. The processor and / or user interface circuitry including the processor may be configured to control one or more functions of one or more user interface elements through computer program instructions (e.g., software and / or firmware) stored on a memory (e.g., memory 1220 and / or the like) accessible to the processor.

[0128] The communications device or circuitry 1240 may be any means, such as a device or circuitry, embodied in either hardware or a combination of hardware and software, configured to receive and / or transmit data from and / or to a network and / or any other device or circuitry in communication with the system 1200. The communications device or circuitry 1240 may include, for example, a network interface for enabling communication with a wired or wireless communication network. For example, the communications device or circuitry 1240 may include one or more network interface cards, antennas, buses, switches, routers, modems, and supporting hardware and / or software, or any other devices suitable for enabling communication over a network. Additionally or alternatively, the communications interface may include circuitry for interacting with an antenna and causing transmission of signals via the antenna or handling reception of signals received via the antenna. The signals may be transmitted by the system 1200 using any of a number of wireless personal area network (PAN) technologies, such as current and future Bluetooth® standards (including Bluetooth® and Bluetooth® Low Energy (BLE)), infrared radio (e.g., IrDA), FREC, ultra-wideband (UWB), inductive radio transmission, or the like. In addition, it should be appreciated that the signals may be transmitted using Wi-Fi, Near Field Communication (NFC), Worldwide Interoperability for Microwave Access (WiMAX), or other proximity-based communication protocols.

[0129] Any such computer program instructions and / or other types of code may be loaded onto a computer, processor, or other programmable device circuitry and executing the code on the machine, such that the computer, processor, or other programmable circuitry produces means for implementing various functions, including those described herein.

[0130] The embodiments of the present disclosure may be configured as systems, methods, mobile devices, back-end network devices, and the like. Thus, the embodiments may comprise various means, including fully hardware or any combination of software and hardware. Furthermore, the embodiments may take the form of a computer program product on at least one non-transitory computer-readable storage medium having computer-readable program instructions (e.g., computer software) embodied in the storage medium. Any suitable computer-readable storage medium may be utilized, including non-transitory hard disks, CD-ROMs, flash memories, optical storage devices, or magnetic storage devices.

[0131] The processing circuitry according to the present disclosure may include one or more processors, microprocessors, controllers, and / or microcontrollers, each of which may be a discrete chip or distributed among several different chips (and portions thereof). The processing circuitry according to the present disclosure may include a digital signal processor, which may be implemented in the hardware and / or software of the processing circuitry according to the present disclosure. The processing circuitry according to the present disclosure may be communicatively coupled to other components of the figures herein. The processing circuitry according to the present disclosure may execute software instructions stored on a memory that cause the processing circuitry to perform different sets of actions and control other components of the figures herein.

[0132] A memory according to the present disclosure can be shared by one or more of the various functional units, or can be distributed among two or more of them (e.g., as separate memories residing in different chips). A memory can also be its own separate chip. A memory can be non-transient, and can be volatile (e.g., RAM, etc.) and / or non-volatile memory (e.g., ROM, Flash memory, F-RAM, etc.).

[0133] Computer program instructions for carrying out operations in accordance with the described subject matter may be written in any combination of one or more programming languages ​​and software platforms, such as, but not limited to, Python, Labview platform by National Instruments, Java, JavaScript, Smalltalk, C++, C#, Transact-SQL, XML, PHP, or the like, and conventional procedural programming languages, such as the "C" programming language or similar programming languages.

[0134] Various aspects of the subject matter are described below as a review of the described embodiments and / or as a complement thereof, with the interrelationships and interchangeability of the following embodiments being emphasized here. In other words, emphasis is placed on the fact that each feature of the embodiments can be combined with any other feature, unless expressly stated otherwise or logically impossible.

[0135] It should be noted that all features, elements, components, functions, and steps described with respect to any embodiment provided herein are intended to be freely combinable and substituted with those from any other embodiment. If a feature, element, component, function, or step is described with respect to only one embodiment, it should be understood that the feature, element, component, function, or step may be used with all other embodiments described herein unless expressly stated otherwise. This paragraph therefore serves as a premise and description aid for the introduction of claims combining features, elements, components, functions, and steps from different embodiments or substituting features, elements, components, functions, and steps from one embodiment with those from another embodiment, wherever applicable, even if the following description does not expressly state that such combinations or substitutions are possible in a particular case. In particular, it is expressly recognized that an explicit enumeration of all possible combinations and substitutions would be unduly burdensome, given that the permissibility of all such combinations and substitutions would be readily recognized by those skilled in the art.

[0136] To the extent that the embodiments disclosed herein include or operate in association with a memory, storage device, and / or computer-readable medium, the memory, storage device, and / or computer-readable medium are non-transitory. Thus, to the extent that the memory, storage device, and / or computer-readable medium are covered by one or more claims, the memory, storage device, and / or computer-readable medium are only non-transitory.

[0137] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0138] While the embodiments are susceptible to various modifications and alternative forms, specific examples thereof are shown in the drawings and described in detail herein. It should be understood, however, that these embodiments are not limited to the particular forms disclosed, but on the contrary, these embodiments are intended to cover all modifications, equivalents, and alternatives falling within the spirit of the disclosure. Furthermore, any feature, function, step, or element of the embodiments may be recited in or added to the claims with a negative limitation that defines the inventive scope of the claims by the feature, function, step, or element that does not fall within its scope.

Claims

1. 1. A computer-implemented method for selecting a raster profile for scanning a proton beam across a target, the method comprising: using a computer processing system to establish a plurality of possible raster profiles for scanning the proton beam across the target, each of the plurality of possible raster profiles comprising one or more beam parameters, each of the one or more beam parameters characterizing a property of the proton beam and one or more path parameters characterizing a path of the proton beam across the target; establishing, using the computer processing system, one or more target parameters that characterize the target; calculating, using the computer processing system, a figure of merit value for each of the potential beam raster profiles, the figure of merit being based on a thermal loading of the target by the proton beam with respect to the corresponding potential raster profile; selecting, using the computer processing system, a raster profile from among the plurality of possible raster profiles based on the value of the figure of merit; directing the proton beam across the target according to the selected raster profile; 4. A computer-implemented method comprising:

2. 2. The computer-implemented method of claim 1, wherein calculating a value for the figure of merit comprises calculating, for each of the possible raster profiles, a thermal load at each of a plurality of discrete portions of the target based on a linear relationship between the thermal load and proton flux at each discrete portion for the corresponding raster profile.

3. 3. The computer-implemented method of claim 2, wherein each discrete portion corresponds to an area of ​​a surface of the target within the path of the proton beam that is smaller than a dimension of the proton beam, and the heat load in each discrete portion is calculated based on heat transfer through a depth of the target away from a surface of the target on which the proton beam is incident.

4. The computer-implemented method of claim 1 , wherein the figure of merit is selected from the group consisting of a peak temperature of the target, a temperature change of the target, an average temperature of the target, and a utilization efficiency of the target.

5. 2. The computer-implemented method of claim 1, wherein the one or more beam parameters are selected from the group consisting of beam dimensions, beam shape, and beam structure, and selecting the raster profile from among the plurality of possible raster profiles based on the value of the figure of merit includes selecting a masked profile configured to avoid one or more portions of the target.

6. 2. The computer-implemented method of claim 1, wherein the one or more path parameters are selected from the group consisting of a frequency associated with the path of the proton beam, a linear velocity of the proton beam across a surface of the target, a number of radial scan layers in a supercycle of the path of the proton beam, and a number of supercycles of the path of the proton beam.

7. The computer-implemented method of claim 1 , wherein the one or more target parameters are selected from the group consisting of a target surface area, a target thickness, and a target composition.

8. The computer-implemented method of claim 1 , wherein the target comprises a layer of lithium or a layer of beryllium.

9. 2. The computer-implemented method of claim 1, further comprising measuring one or more properties of the target and selecting the raster profile based on the measured properties of the target, wherein the one or more properties of the target comprise a temperature of the target at one or more locations on the target.

10. The computer-implemented method of claim 1 , further comprising measuring one or more properties of the beam and selecting the raster profile based on the measured properties of the beam.

11. The computer-implemented method of claim 10 , wherein the one or more properties of the beam are measured upstream from the target.

12. 2. The computer-implemented method of claim 1, wherein the selected raster profile defines a path for the proton beam having a minimum delay between successive exposures of a single location of the target to the proton beam that exceeds a threshold period.

13. 13. The computer-implemented method of claim 12, wherein the selected raster profile defines a path based on a trochoidal shape, the trochoidal shape comprising multiple lobes, and an angular frequency of the proton beam varies for different lobes of the trochoidal shape.

14. 2. The computer-implemented method of claim 1, wherein the selected raster profile comprises different angular velocities of the proton beam across the target surface and / or different linear velocities of the proton beam across the target surface.

15. A beam system comprising:

1. A computing device comprising: a processor communicatively coupled to a memory, the memory storing a plurality of instructions that, when executed by the processor, establishing a plurality of possible raster profiles for scanning a proton beam across a target, each of the plurality of possible raster profiles comprising one or more beam parameters, each of the one or more beam parameters characterizing a property of the proton beam and one or more path parameters characterizing a path of the proton beam across the target; establishing one or more target parameters characterizing said target; calculating a figure of merit value for each of the potential beam raster profiles, the figure of merit being based on a thermal loading of the target by the proton beam for the corresponding potential raster profile; selecting a raster profile from among the plurality of possible raster profiles based on the value of the figure of merit; generating a signal to direct the proton beam across the target in accordance with the selected raster profile; The beam system further comprises:

Images