Abstract: A circular accelerator that accelerates charged particles orbiting along an orbital path to a predetermined energy to perform, by deviating the path from the orbital path to an extraction path, extraction of the charged particles exceeding a stable region formed by multipole electromagnets, includes a multipole electromagnet energization control unit setting energization of the multipole electromagnets so that part of the charged particles are deviated to a discarding path other than the extraction path to discard unwanted charged particles, and then setting energization of the multipole electromagnets so that the charged particles orbiting in the orbital path are deviated to the extraction path to perform extraction of the charged particles.

Abstract: A device controller controls an acceleration-related devices and an extraction-related devices of an accelerator for accelerating and extracting a particle beam, in such a way that the controller checks, at a time point when receiving a master clock pulse, that preparation for operating the acceleration-related devices is completed and then commands the acceleration-related devices to operate in accordance with an operation pattern corresponding to a prescribed energy of the particle beam, and commands the acceleration-related devices to operate in accordance with an extracting operation pattern when an extraction enable signal indicating that the particle beam reaches the prescribed energy is turned ON and an extraction-related device setting-status signal indicating that completion of setting the extraction-related devices for the prescribed energy is ON.

Abstract: In a beam transport system, based on a beam temporal-variation related amount that has been calculated by a beam analyzer and that is a beam-position temporal variation amount or a beam diameter at a beam profile monitor, an optical parameter calculator calculates a start-point momentum dispersion function that is a momentum dispersion function (?, ??) of a charged particle beam at a start point in design of the beam transport system that is set on a beam trajectory of the accelerator; and calculates optical parameters using, as an initial condition, the start-point momentum dispersion function and a beginning condition at an irradiation position at the time of detecting profile data.

Abstract: A device controller controls an acceleration-related devices and an extraction-related devices of an accelerator for accelerating and extracting a particle beam, in such a way that the controller checks, at a time point when receiving a master clock pulse, that preparation for operating the acceleration-related devices is completed and then commands the acceleration-related devices to operate in accordance with an operation pattern corresponding to a prescribed energy of the particle beam, and commands the acceleration-related devices to operate in accordance with an extracting operation pattern when an extraction enable signal indicating that the particle beam reaches the prescribed energy is turned ON and an extraction-related device setting-status signal indicating that completion of setting the extraction-related devices for the prescribed energy is ON.

Abstract: A circular accelerator that accelerates charged particles orbiting along an orbital path to a predetermined energy to perform, by deviating the path from the orbital path to an extraction path, extraction of the charged particles exceeding a stable region formed by multipole electromagnets, includes a multipole electromagnet energization control unit setting energization of the multipole electromagnets so that part of the charged particles are deviated to a discarding path other than the extraction path to discard unwanted charged particles, and then setting energization of the multipole electromagnets so that the charged particles orbiting in the orbital path are deviated to the extraction path to perform extraction of the charged particles.

Abstract: When an energy of a particle beam to be emitted from an accelerator is set for every slice group including two or more adjacent slices and an attenuation amount is set for each slice in the slice group, the energy to be emitted from the accelerator is set, for every slice group, higher than an energy corresponding to the slice at a deepest location in that slice group so that a transmissive plate has a predetermined thickness for the slice at the deepest location; and, with respect to a thickness of the transmissive plate to be set for every slice group, the thickness set for the slice group at a deep location is larger than or equal to the thickness set for the slice group at a shallow location, and the thickness set for the slice group at a deepest location is thicker than the thickness set for the slice group at a shallowest location.

Abstract: A method of manufacturing a radio frequency accelerator that accelerates charged particles injected into a second-stage linear accelerator from a first-stage linear accelerator includes a step of setting a value of a power distribution factor R for the power distributor to supply radio frequency power to the second-stage linear accelerator and a value of a ratio L/? of a length L of the matching section between the outlet of the first-stage linear accelerator and the inlet of the second-stage linear accelerator to the angular frequency ? of the radio frequency power, so that a charged particle beam is extracted from the second-stage linear accelerator over a range of the total radio frequency power wider than a widest allowable range among allowable total radio frequency power ranges determined for each phase of charged particles on the basis of phase acceptance of the second-stage accelerator.

Abstract: A particle beam treatment system includes an accelerator system that accelerates a charged particle beam and a beam transport system that transports a high-energy beam emitted from the accelerator to an irradiation location, wherein the beam transport system is provided with at least one steering electromagnet and at least one beam position monitor corresponding to the at least one steering electromagnet, and wherein the at least one beam position monitor supplies an excitation current for correcting a beam position, which periodically varies, to the at least one steering electromagnet.

Abstract: In a beam transport system, based on a beam temporal-variation related amount that has been calculated by a beam analyzer and that is a beam-position temporal variation amount or a beam diameter at a beam profile monitor, an optical parameter calculator calculates a start-point momentum dispersion function that is a momentum dispersion function (?, ??) of a charged particle beam at a start point in design of the beam transport system that is set on a beam trajectory of the accelerator; and calculates optical parameters using, as an initial condition, the start-point momentum dispersion function and a beginning condition at an irradiation position at the time of detecting profile data.

Abstract: When an energy of a particle beam to be emitted from an accelerator is set for every slice group including two or more adjacent slices and an attenuation amount is set for each slice in the slice group, the energy to be emitted from the accelerator is set, for every slice group, higher than an energy corresponding to the slice at a deepest location in that slice group so that a transmissive plate has a predetermined thickness for the slice at the deepest location; and, with respect to a thickness of the transmissive plate to be set for every slice group, the thickness set for the slice group at a deep location is larger than or equal to the thickness set for the slice group at a shallow location, and the thickness set for the slice group at a deepest location is thicker than the thickness set for the slice group at a shallowest location.

Abstract: A method of manufacturing a radio frequency accelerator that accelerates charged particles injected into a second-stage linear accelerator from a first-stage linear accelerator includes a step of setting a value of a power distribution factor R for the power distributor to supply radio frequency power to the second-stage linear accelerator and a value of a ratio L/? of a length L of the matching section between the outlet of the first-stage linear accelerator and the inlet of the second-stage linear accelerator to the angular frequency ? of the radio frequency power, so that a charged particle beam is extracted from the second-stage linear accelerator over a range of the total radio frequency power wider than a widest allowable range among allowable total radio frequency power ranges determined for each phase of charged particles on the basis of phase acceptance of the second-stage accelerator.

Abstract: A particle therapy apparatus has a rotating gantry configured in such a way that an irradiation device is rotated around a rotation axis and a particle beam is irradiated onto an irradiation subject; the rotating gantry is provided with an entrance-side deflection electromagnet having a deflection path for radially deflecting the particle beam supplied along the rotation axis so as to guide the particle beam to the irradiation device and a straight path that is switchable with the deflection path and is for making the supplied particle beam travel in a straight manner; there are provided trajectory correcting devices having two position sensors that are arranged along the rotation axis so as to flank the entrance-side deflection electromagnet.

Abstract: In gantry type particle beam irradiation system comprising a gantry and being configured to irradiate a particle beam, which has small emittance in X direction and large emittance in Y direction at an extraction position of a circular accelerator, from an irradiation nozzle installed in the gantry to an irradiation target, the irradiation nozzle has a ridge filter which is installed so as for a direction in which emittance in X direction is maintained to tilt to a direction which is perpendicular to a ridge of the ridge filter by a predetermined angle in the state where the gantry is a reference angle.

Abstract: A charged particle beam transport system is characterized in that in a fixed transport unit, a phase of a phase space distribution of a charged particle beam at an inlet of a rotating deflection unit that rotates around an gantry rotation axle of a rotating gantry coincides with a phase determined by a calculation based on an average value of a first phase advance and a second phase advance. The first phase advance is defined as a change in a phase, of the phase space distribution, that changes when the charged particle beam travels from the inlet of the rotating deflection unit to an isocenter in the case where a gantry angle is a gantry reference angle; the second phase advance is defined as a change in a phase at a time when the gantry angle is pivoted by 90° from the gantry reference angle.

Abstract: A charged particle beam transport system is characterized in that in a fixed transport unit, a phase of a phase space distribution of a charged particle beam at an inlet of a rotating deflection unit that rotates around an gantry rotation axle of a rotating gantry coincides with a phase determined by a calculation based on an average value of a first phase advance and a second phase advance. The first phase advance is defined as a change in a phase, of the phase space distribution, that changes when the charged particle beam travels from the inlet of the rotating deflection unit to an isocenter in the case where a gantry angle is a gantry reference angle; the second phase advance is defined as a change in a phase at a time when the gantry angle is pivoted by 90° from the gantry reference angle.

Abstract: In gantry type particle beam irradiation system comprising a gantry and being configured to irradiate a particle beam, which has small emittance in X direction and large emittance in Y direction at an extraction position of a circular accelerator, from an irradiation nozzle installed in the gantry to an irradiation target, the irradiation nozzle has a ridge filter which is installed so as for a direction in which emittance in X direction is maintained to tilt to a direction which is perpendicular to a ridge of the ridge filter by a predetermined angle in the state where the gantry is a reference angle.

Abstract: A septum magnet includes a yoke that can be separated at the approximately center portion thereof in the axis direction; a septum coil; a return coil; and a vacuum duct that is inserted between the septum coil and the return coil. The septum coil is formed in such a way as to be able to be separated into a first portion and a second portion in response to separation of the yoke; and in a space between the septum coil and the vacuum duct, there is provided an auxiliary coil, in two portions of which, corresponding to the first portion and the second portion of the septum coil, electric currents flow in opposite direction to each other in a circumferential direction.

Abstract: A particle beam treatment system includes an accelerator system that accelerates a charged particle beam and a beam transport system that transports a high-energy beam emitted from the accelerator to an irradiation location, wherein the beam transport system is provided with at least one steering electromagnet and at least one beam position monitor corresponding to the at least one steering electromagnet, and wherein the at least one beam position monitor supplies an excitation current for correcting a beam position, which periodically varies, to the at least one steering electromagnet.

Abstract: A circular accelerator comprises a target current value memory which stores a target current value of a beam current of charged particle which is extracted from an extracting device; and a frequency determination part in which a frequency change ratio is obtained by performing a feedback control based on an error signal between a detection signal of a beam current detector and a target current value which is stored in a target current value memory, and determines a subsequent frequency from the obtained frequency change ratio and a current frequency, wherein the subsequent frequency which is determined by the frequency determination part is stored in a frequency memory and a radio-frequency generator generates the subsequent radio-frequency of frequency which is determined.

Abstract: The present invention is intended to enable proper elimination of the remanent magnetization of the scanning magnet, which is used in a particle beam therapy system, in a short time. In the particle beam therapy system that irradiates an irradiation target with a particle beam 18 accelerated by an accelerator and scanned by scanning magnets 11 and 12, power supplies 13 and 14 to operate the scanning magnets 11 and 12 output pattern currents for demagnetizing the scanning magnets 11 and 12. The pattern current is controlled by a control circuit 15 that reads a demagnetization pattern 17 and controls the power supplies 13 and 14.