MAGNETIC FIELD REGENERATOR

• US 20170231081A1
• Filed: 02/24/2017
• Published: 08/10/2017
• Est. Priority Date: 09/28/2012
• Status: Active Grant

• Current Assignee: Mevion Medical Systems Incorporated
• Original Assignee: Mevion Medical Systems Incorporated
• Inventors: Van der Laan, Jan, Gall, Kenneth P., Zwart, Gerrit Townsend, Franzen, Ken Yoshiki
• Granted Patent: US 10,368,429 B2
• Time in Patent Office: Days
• CPC Class Codes: A61N 2005/1087 Ions; Protons
• CPC Class Codes: A61N 5/1077 Beam delivery systems
• CPC Class Codes: H05H 13/02 Synchrocyclotrons, i.e. frequency modulated cyclotrons
• CPC Class Codes: H05H 2007/025 Radiofrequency systems
• CPC Class Codes: H05H 2007/046 for beam deflection
• CPC Class Codes: H05H 7/02 Circuits or systems for supplying or feeding radio-frequency energy radio-frequency generators H03B
• CPC Class Codes: H05H 7/04 Magnet systems , e.g. undulators, wigglers free-electron laser H01S3/0903; Energisation thereof
• CPC Class Codes: H05H 7/10 Arrangements for ejecting particles from orbits

Abstract

An example particle accelerator includes the following: a voltage source to provide a radio frequency (RF) voltage to a cavity to accelerate particles from a plasma column, where the cavity has a magnetic field causing particles accelerated from the plasma column to move orbitally within the cavity; an extraction channel to receive the particles accelerated from the plasma column and to output the received particles from the cavity; and a regenerator to provide a magnetic field bump within the cavity to thereby change successive orbits of the particles accelerated from the plasma column so that, eventually, particles output to the extraction channel. The magnetic field is at least 6 Tesla and the magnetic field bump is at most 2 Tesla.

Claims

1. A particle accelerator comprising:

a voltage source to provide a radio frequency (RF) voltage to a cavity to accelerate particles from a plasma column, the cavity having a magnetic field causing particles accelerated from the plasma column to move orbitally within the cavity;

an extraction channel to receive the particles accelerated from the plasma column and to output the received particles from the cavity; and

a regenerator to provide a magnetic field bump within the cavity to thereby change successive orbits of the particles accelerated from the plasma column so that, eventually, particles output to the extraction channel;

wherein the magnetic field is at least 6 Tesla and the magnetic field bump is at most 2 Tesla.

2. The particle accelerator of claim 1, wherein the regenerator comprises a ferromagnetic arrangement located at a radial location from the plasma column.

3. The particle accelerator of claim 2, wherein the regenerator comprises a single ferromagnetic arrangement.

4. The particle accelerator of claim 2, wherein the ferromagnetic structure includes steel.

5. The particle accelerator of claim 1, wherein the magnetic field is at least 4 Tesla and the magnetic field bump is at most 2 Tesla.

6. The particle accelerator of claim 1, wherein the regenerator has an irregular cross-sectional shape that is designed to produce a magnetic field bump have a specific shape and/or magnitude.

7. The particle accelerator of claim 6, wherein the cross-sectional irregular shape comprises an angular feature on a portion of the regenerator facing towards the cavity, the angular feature comprising an edge comprising a non-orthogonal intersection of two faces.

8. The particle accelerator of claim 1, wherein the extraction channel comprises a septum that separates particles entering the extraction channel from particles remaining in the cavity, the regenerator being configured so that a pitch and an angle of a particle orbit enable a majority of particles in the particle orbit to pass over the septum and into the extraction channel.

9. The particle accelerator of claim 1, wherein the particle orbit passing over the septum comprise a range of radii of particles relative to the plasma column.

10. A proton therapy system comprising:

the particle accelerator of claim 1; and

a gantry on which the synchrocyclotron is mounted, the gantry being rotatable relative to a patient position;

wherein protons are output essentially directly from the synchrocyclotron to the patient position.

11. The proton therapy system of claim 10, wherein the particle accelerator comprises a synchrocyclotron.

12. A particle accelerator comprising:

a particle source to provide pulses of ionized plasma to a cavity;

a voltage source to provide a radio frequency (RF) voltage to the cavity to accelerate particles from the plasma column outwardly, the particles accelerated from the plasma column traveling in orbits within the cavity;

an extraction channel to receive orbits of particles from the cavity for output from the particle accelerator and

a regenerator to provide a magnetic field bump within the cavity to shape the orbits of the particles in order to direct the orbits of particles to the extraction channel.

13. The particle accelerator of claim 12, wherein the magnetic field is at least 4 Tesla.

14. The particle accelerator of claim 12, wherein the magnetic field bump is at most 2 Tesla.

15. The particle accelerator of claim 12, wherein the regenerator is movable in one or more dimensions relative to the plasma column.

16. The particle accelerator of claim 12, wherein the regenerator has an irregular cross-sectional shape that is designed to produce a magnetic field bump have a specific shape and/or magnitude.

17. The particle accelerator of claim 16, wherein the cross-sectional irregular shape comprises an angular feature on a portion of the regenerator facing towards the cavity, the angular feature comprising an edge comprising a non-orthogonal intersection of two faces.

18. The particle accelerator of claim 12, wherein the extraction channel comprises a septum that separates particles entering the extraction channel from particles remaining in the cavity, the regenerator being configured so that a pitch and an angle of a particle orbit enable a majority of particles in the particle orbit to pass over the septum and into the extraction channel.

19. The particle accelerator of claim 12, wherein the particle orbit passing over the septum comprise a range of radii of particles relative to the plasma column.

20. A proton therapy system comprising:

the particle accelerator of claim 12; and

a gantry on which the particle accelerator is mounted, the gantry being rotatable relative to a patient position;

wherein protons are output essentially directly from the particle accelerator to the patient position.

21. The proton therapy system of claim 20, wherein the particle accelerator comprises a synchrocyclotron.

22. A particle accelerator comprising:

a voltage source to provide a radio frequency (RF) voltage to a cavity to accelerate particles from a plasma column, the cavity having a magnetic field causing particles accelerated from the plasma column to move orbitally within the cavity;

an extraction channel to receive the particles accelerated from the plasma column and to output the received particles from the cavity; and

a regenerator to provide a magnetic field bump within the cavity to thereby change successive orbits of the particles accelerated from the plasma column so that, eventually, particles output to the extraction channel;

wherein the particle accelerator is configured to vary an energy of the particles that move orbitally within the cavity.

23. The particle accelerator of claim 22, wherein the regenerator is movable in one or more dimensions within the cavity, movement of the regenerator being correlated to an energy of the particles.

24. The particle accelerator of claim 22, further comprising:

coils to pass current to generate the magnetic field, wherein a variation in the amount of current through the coils corresponds to a variation in an energy of the particles.

25. The particle accelerator of claim 22, further comprising:

an energy degrader to affect an energy of a particle beam output from the particle accelerator.