Charged particle beam irradiation apparatus and method of irradiation with charged particle beam
First Claim
1. A charged particle beam irradiation apparatus comprising:
- scanning magnetic field generating means comprising two electromagnets arranged in series along a direction of an incident axis of a charged particle beam and deflecting the charged particle beam in opposite directions,energy modulating means comprising a cylindrical member having a length and a distribution of wall thickness in a circumferential direction, means for rotating the cylindrical member around a rotation axis, and detecting means for detecting angle of rotation of the cylindrical member, the energy modulating means being disposed at a downstream side of the scanning magnetic field generating means so that the charged particle beam passes through the rotation axis,energy attenuating means for limiting energy of the charged particle beam, andmeans for rotating the scanning magnetic field generating means and the energy modulating means together around the incident axis of the charged particle beam.
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Accused Products
Abstract
A charged particle beam irradiation apparatus includes two electromagnets arranged in series along a direction of an incident axis of a charged particle beam, for deflecting the charged particle beam in opposite directions, an energy modulator including a cylindrical member having a length and a distribution of wall thickness in a circumferential direction, a first rotational drive for rotating the cylindrical member around a rotation axis, and a detector for detecting the angular position of the cylindrical member. The energy modulator is disposed at a downstream side of the scanning electromagnets so that the deflected charged particle beam passes through the rotation axis. The apparatus includes an energy degrader for limiting energy of the charged particle beam, and a second rotational drive for rotating the scanning electromagnets and the energy modulator together around the incident axis of the charged particle beam.
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Citations
7 Claims
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1. A charged particle beam irradiation apparatus comprising:
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scanning magnetic field generating means comprising two electromagnets arranged in series along a direction of an incident axis of a charged particle beam and deflecting the charged particle beam in opposite directions, energy modulating means comprising a cylindrical member having a length and a distribution of wall thickness in a circumferential direction, means for rotating the cylindrical member around a rotation axis, and detecting means for detecting angle of rotation of the cylindrical member, the energy modulating means being disposed at a downstream side of the scanning magnetic field generating means so that the charged particle beam passes through the rotation axis, energy attenuating means for limiting energy of the charged particle beam, and means for rotating the scanning magnetic field generating means and the energy modulating means together around the incident axis of the charged particle beam. - View Dependent Claims (2, 3, 4)
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5. A method of irradiation with a charged particle beam with a charged particle beam irradiation apparatus comprising:
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scanning magnetic field generating means comprising two electromagnets arranged in series along a direction of an incident axis of a charged particle beam and deflecting the charged particle beam in opposite directions, energy modulating means comprising a cylindrical member having a length and a distribution of wall thickness in a circumferential direction, means for rotating the cylindrical member around a rotation axis, and detecting means for detecting angle of rotation of the cylindrical member, the energy modulating means being disposed at a downstream side of the scanning magnetic field generating means so that the charged particle beam passes through the rotation axis, energy attenuating means for limiting energy of the charged particle beam, and means for rotating the scanning magnetic field generating means and the energy modulating means together around the incident axis of the charged particle beam, the method comprising irradiating a three-dimensional irradiation area by; approximating the three-dimensional irradiation area as a group of cylindrical columns arranged parallel to an incidence direction z of an incident charged particle beam wherein a coordinate Pi of the center of each cylindrical column in an XY direction is the beam irradiation position, a length Δ
zi of each cylindrical column is a scanning range in a beam propagating direction (a depth direction) at the beam irradiation position Pi, and the coordinate of the maximum depth of irradiation is zi;loading as previously prepared parameters Pi, Δ
zi and zi, and i=1, 2, . . . N for the irradiation area from a set table;determining an angle of rotation and a strength of a magnetic field of the scanning magnetic field generating means and an angle of rotation of the energy modulating means in response to each Pi; determining the maximum energy of the charged particle beam with the energy attenuating means in response to the maximum depth of irradiation zi; and determining an effective range of the angle of rotation based on data from the energy modulating means in response to the scanning range of depth Δ
zi (initial value i=1), and irradiating with the charged particle beam within the effective range. - View Dependent Claims (6, 7)
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Specification