Accelerators and treatment systems

Abstract

[Problem] This invention provides an accelerator and treatment system that can be further miniaturized. [Solution] An accelerator (10) accelerates charged particles (Q) as they circulate on an orbital plane (PL). The accelerator (10) has a pair of magnetic poles (2) that face each other across the orbital plane (PL) to form a magnetic field required to accelerate the charged particles (Q). Between the pair of magnetic poles (2), along the circumferential orbit (CO) of the charged particles (Q), alternating hill regions (2h) and valley regions (2v) with lower magnetic flux density than the hill regions (2h) are formed. A pressure-reducing section (4) is provided in the valley region (2v) to reduce the magnetic flux density of the valley region (2v).

Claims

1. An accelerator that causes charged particles to circulate and accelerate on an orbital plane, the accelerator having a pair of magnetic poles facing each other across the orbital plane to form a magnetic field required to accelerate the charged particles, wherein between the pair of magnetic poles, along the circumferential orbit of the charged particles, a hill region and a valley region with a lower magnetic flux density than the hill region are alternately formed, and a pressure-reducing part is provided in the valley region for reducing the magnetic flux density of the valley region.

2. As in request item 1, the accelerator, where, The aforementioned pressure-lowering part includes at least one of a coil and a diamagnetic body.

3. As in request item 2, the accelerator, where, The aforementioned accelerator is an isochronous cyclotron accelerator.

4. As in request item 3, the accelerator, where, The aforementioned pressure-lowering portion contains a superconductor.

5. As in request item 4, the accelerator, where, It further includes a heating device for heating the aforementioned depressed portion.

6. As in request item 4 or 5, the accelerator, where, The aforementioned superconductor is a high-temperature superconductor.

7. An accelerator as requested in item 1 or 2, wherein, When viewed from a direction perpendicular to the aforementioned orbital plane, the aforementioned hill region is formed as a spiral sector shape extending outward from the center of the aforementioned circumferential orbit of the aforementioned charged particle.

8. An accelerator as requested in item 1 or 2, wherein, The aforementioned depressed portion forms a block.

9. An accelerator as requested in item 3 or 4, wherein, Further comprising: a main coil, which is respectively disposed around the aforementioned pair of magnetic poles to generate a magnetic field required to accelerate the aforementioned charged particles between the aforementioned pair of magnetic poles; the aforementioned orbital surface side of the aforementioned magnetic pole has a mound surface that overlaps with the aforementioned mound region when viewed from the opposite direction of the aforementioned pair of magnetic poles; in the direction perpendicular to the orbital surface of the aforementioned pair of magnetic poles, the aforementioned mound surface is located closer to the orbital surface side than the aforementioned orbital surface side of the aforementioned main coil.

10. An accelerator as requested in item 1 or 2, wherein, The end of the center side of the aforementioned circumferential track of the aforementioned depressed portion is located further outside the aforementioned circumferential track than the end of the center side of the aforementioned circumferential track of the aforementioned hill region.

11. An accelerator as requested in item 1 or 2, wherein, The aforementioned pressure portion is fixed to the aforementioned magnetic pole by a non-magnetic body.

12. As in request item 5, the accelerator, where, The accelerator further comprises: a main coil disposed around the aforementioned pair of magnetic poles to generate a magnetic field between the aforementioned pair of magnetic poles required to accelerate the aforementioned charged particles; the accelerator includes a control unit that controls the amount of current flowing through the aforementioned main coil while controlling the aforementioned heating device; the aforementioned control unit performs the following steps: a first step, supplying a first current value to the aforementioned main coil while heating the aforementioned pressure-lowering part using the aforementioned heating device; a second step, after the aforementioned first step, stopping the heating of the aforementioned pressure-lowering part; and a third step, after the aforementioned second step, supplying a second current value higher than the aforementioned first current value to the aforementioned main coil.

13. As in request item 8, the accelerator, where, The aforementioned block comprises a plurality of circular blocks formed in the shape of a circular plate, which are laid out in the aforementioned valley region when viewed from the opposite direction of the aforementioned pair of magnetic poles.

14. A treatment system that uses charged particles accelerated by the accelerator of claim 1 for treatment.

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