A particle therapy system in which the efficiency of extracting a beam from a synchrotron can be improved and time required for therapy can be shortened is provided. The synchrotron 10 of the particle therapy system 100 extracts a charged particle beam, which circulates in the synchrotron 10, out of the synchrotron 10 by means of a slow extraction method using the resonance of a betatron oscillation, and magnetic poles 73 included in a bending magnet 12 of the synchrotron 10 have a SIM structure that generates a magnetic field distribution that makes the horizontal tune of the charged particle more closely approach a resonant line used in the slow extraction method as the amplitude of the horizontal betatron oscillation of a charged particle included in the charged particle beam becomes larger.

A particle therapy system in which the efficiency of extracting a beam from a synchrotron can be improved and time required for therapy can be shortened is provided. The synchrotron 10 of the particle therapy system 100 extracts a charged particle beam, which circulates in the synchrotron 10, out of the synchrotron 10 by means of a slow extraction method using the resonance of a betatron oscillation, and magnetic poles 73 included in a bending magnet 12 of the synchrotron 10 have a SIM structure that generates a magnetic field distribution that makes the horizontal tune of the charged particle more closely approach a resonant line used in the slow extraction method as the amplitude of the horizontal betatron oscillation of a charged particle included in the charged particle beam becomes larger.

Method includes providing a substrate layer, depositing a first layer along an exposed side of the substrate layer, and depositing a second layer along an exposed side of the first layer such that the first layer is disposed between the substrate layer and the second layer. One of the first or second layers is a backing layer and the other is a conductive layer. The first and second layers form a stripping sheet that is configured to strip electrons from charged particles passing through the stripping sheet. The method also includes removing at least a portion of the substrate layer.

Method includes providing a substrate layer, depositing a first layer along an exposed side of the substrate layer, and depositing a second layer along an exposed side of the first layer such that the first layer is disposed between the substrate layer and the second layer. One of the first or second layers is a backing layer and the other is a conductive layer. The first and second layers form a stripping sheet that is configured to strip electrons from charged particles passing through the stripping sheet. The method also includes removing at least a portion of the substrate layer.

A charge stripping method includes irradiating a charge stripping film with an ion beam. The charge stripping film includes a single layer body of a graphitic film having a carbon component of at least 96 at % and a thermal conductivity in a film surface direction at 25 C. of at least 800 W/mK, or a laminated body of the graphitic film. The charge stripping film has a thickness of not less than 100 nm and less than 10 m, a tensile strength in a film surface direction of at least 5 MPa, a coefficient of thermal expansion in the film surface direction of not more than 110.sup.5/K, and an area of at least 4 cm.sup.2.

A charge stripping method includes irradiating a charge stripping film with an ion beam. The charge stripping film includes a single layer body of a graphitic film having a carbon component of at least 96 at % and a thermal conductivity in a film surface direction at 25 C. of at least 800 W/mK, or a laminated body of the graphitic film. The charge stripping film has a thickness of not less than 100 nm and less than 10 m, a tensile strength in a film surface direction of at least 5 MPa, a coefficient of thermal expansion in the film surface direction of not more than 110.sup.5/K, and an area of at least 4 cm.sup.2.

A cyclotron for accelerating a beam of charged particles and extracting the beam. The cyclotron includes a vacuum chamber; a target support element sealed and coupled to the vacuum chamber and including a tubular channel leading to a target; first energy specific extraction kit including a first stripper assembly with a stripper located at a first stripping position for stripping charged particles at a first energy and a second energy specific extraction kit for driving modified charged particles of second energy along a second extraction path towards a target holder, wherein the energy specific extraction kit includes: a second stripper assembly with a stripper located at a second stripping position for stripping charged particles at a second energy and an insert for modifying an orientation of the tubular channel to match the second extraction path such that the modified charged particles of second energy intercept the target holder.

A cyclotron for accelerating a beam of charged particles and extracting the beam. The cyclotron includes a vacuum chamber; a target support element sealed and coupled to the vacuum chamber and including a tubular channel leading to a target; first energy specific extraction kit including a first stripper assembly with a stripper located at a first stripping position for stripping charged particles at a first energy and a second energy specific extraction kit for driving modified charged particles of second energy along a second extraction path towards a target holder, wherein the energy specific extraction kit includes: a second stripper assembly with a stripper located at a second stripping position for stripping charged particles at a second energy and an insert for modifying an orientation of the tubular channel to match the second extraction path such that the modified charged particles of second energy intercept the target holder.

A particle accelerator includes: a pair of magnetic poles disposed to face each other; a coil which surrounds each of the magnetic poles and generates a first magnetic flux density directing from the magnetic pole on one side to the magnetic pole on the other side; a foil stripper provided on a circling orbit of charged particles to strip off electrons from the charged particles; and a magnetic flux density adjustment unit which generates a second magnetic flux density directing in an opposite direction to a direction of the first magnetic flux density, in which the magnetic flux density adjustment unit makes an absolute value of magnetic flux density at a position of the foil stripper when viewed in a plan view smaller than an absolute value of the first magnetic flux density.

A particle accelerator includes: a pair of magnetic poles disposed to face each other; a coil which surrounds each of the magnetic poles and generates a first magnetic flux density directing from the magnetic pole on one side to the magnetic pole on the other side; a foil stripper provided on a circling orbit of charged particles to strip off electrons from the charged particles; and a magnetic flux density adjustment unit which generates a second magnetic flux density directing in an opposite direction to a direction of the first magnetic flux density, in which the magnetic flux density adjustment unit makes an absolute value of magnetic flux density at a position of the foil stripper when viewed in a plan view smaller than an absolute value of the first magnetic flux density.