Active return system

• US 8,791,656 B1
• Filed: 05/31/2013
• Issued: 07/29/2014
• Est. Priority Date: 05/31/2013
• Status: Active Grant

• Current Assignee: Mevion Medical Systems Incorporated
• Original Assignee: Mevion Medical Systems Incorporated
• Inventors: Zwart, Gerrit Townsend, Cooley, James
• Primary Examiner(s): Owens, Douglas W
• Assistant Examiner(s): Sathiraju, Srinivas
• Application Number:
  US13/907,601
• Time in Patent Office: 424 Days
• Field of Search: None
• US Class Current: 315/503
• CPC Class Codes: H05H 13/005 Cyclotrons
• CPC Class Codes: H05H 13/02 Synchrocyclotrons, i.e. frequency modulated cyclotrons
• CPC Class Codes: H05H 7/04 Magnet systems , e.g. undulators, wigglers free-electron laser H01S3/0903; Energisation thereof

Abstract

An example particle accelerator includes a magnet to generate a magnetic field, where the magnet includes first superconducting coils to pass current in a first direction to thereby generate the first magnetic field, and where the first magnetic field is at least 4 Tesla (T). The example particle accelerator also includes an active return system including second superconducting coils. Each of the second superconducting coils surrounds, and is concentric with, a corresponding first superconducting coil. The second superconducting coils are for passing current in a second direction that is opposite to the first direction to thereby generate a second magnetic field having a magnetic field of at least 2.5 T. The second magnetic field has a polarity that is opposite to a polarity of the first magnetic field.

Claims

1. A particle accelerator comprising:

a magnet to generate a magnetic field, the magnet comprising first superconducting coils to pass current in a first direction to thereby generate the first magnetic field, the first magnetic field being at least 4 Tesla (T);

an active return system comprising second superconducting coils, each of the second superconducting coils surrounding, and being concentric with, a corresponding first superconducting coil, the second superconducting coils for passing current in a second direction that is opposite to the first direction to thereby generate a second magnetic field having a magnetic field of at least 2.5 T, the second magnetic field having a polarity that is opposite to a polarity of the first magnetic field; and

a single structure on which at least one first superconducting coil and corresponding second superconducting coil are mounted.

2. The particle accelerator of claim 1, further comprising:

a power supply to provide current to both the first superconducting coils and to the second superconducting coils.

3. The particle accelerator of claim 1, wherein the first superconducting coils and the second superconducting coils are all mounted on the single structure.

4. The particle accelerator of claim 3, wherein the first superconducting coils are mounted on an interior of the single structure and the second superconducting coils are mounted on an exterior of the single structure such that the second superconducting coils are separated from the first superconducting coils by at least part of the single structure.

5. The particle accelerator of claim 3, further comprising:

a banding ring around at least one of the second superconducting coils.

6. The particle accelerator of claim 3, wherein the single structure comprises at least one of stainless steel and carbon fiber.

7. The particle accelerator of claim 1, further comprising:

magnetic pole pieces defining the cavity, the single structure being around at least part of the magnetic pole pieces.

8. The particle accelerator of claim 7, further comprising:

a cryostat cover around at least part of the single structure and at least part of the magnetic pole pieces, the cryostat cover comprising a non-ferromagnetic material.

9. The particle accelerator of claim 1, which weighs less than 15 tons.

10. The particle accelerator of claim 1, which weighs less than 10 tons.

11. A proton therapy system comprising:

the particle accelerator of claim 1; and

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

wherein the proton therapy system is configured to output protons essentially directly from the particle accelerator to the patient position.

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

13. The proton therapy system of claim 11, wherein the particle accelerator comprises:

a particle source to provide ionized plasma to a cavity containing the first magnetic field; and

a voltage source to provide voltage to accelerate a beam comprised of pulses of ionized plasma towards an exit.

14. A particle accelerator comprising:

a voltage source to provide a radio frequency (RF) voltage to a cavity to accelerate particles to produce a particle beam, the cavity having a first magnetic field for causing particles accelerated from the plasma column to move orbitally within the cavity, the RF voltage being controllable to vary in time as the particle beam increases in distance from the plasma column;

a magnet to generate the first magnetic field in the cavity, the magnet comprising first superconducting coils to pass current in a first direction to thereby generate the first magnetic field;

an active return system comprising second superconducting coils, each of the second superconducting coils surrounding, and being concentric with, a corresponding first superconducting coil, the second superconducting coils for passing current in a second direction that is opposite to the first direction to thereby generate a second magnetic field having a magnetic field of at least 2.5 Tesla (T), the second magnetic field having a polarity that is opposite to a polarity of the first magnetic field; and

a single structure on which at least one first superconducting coil and corresponding second superconducting coil are mounted.

15. The particle accelerator of claim 14, wherein the first magnetic field is least 4 T.

16. The particle accelerator of claim 15, wherein the second magnetic field is at between 2.5 T and 12 T.

17. The particle accelerator of claim 14, wherein the first magnetic field is between 4 T and 20 T and the second magnetic field is between 2.5 T and 12 T.

18. The particle accelerator of claim 14, further comprising:

a single power supply to provide current to both the first superconducting coils and to the second superconducting coils.

19. The particle accelerator of claim 14, wherein the first superconducting coils and the second superconducting coils are all mounted on the single structure.

20. The particle accelerator of claim 19, wherein the first superconducting coils are mounted on an interior of the single structure and the second superconducting coils are mounted on an exterior of the single structure such that the second superconducting coils are separated from the first superconducting coils by at least part of the single structure.

21. The particle accelerator of claim 19, further comprising:

a banding ring around at least one of the second superconducting coils.

22. The particle accelerator of claim 19, wherein the single structure comprises at least one of stainless steel and carbon fiber.

23. The particle accelerator of claim 14, further comprising:

magnetic pole pieces defining the cavity, the single structure being around at least part of the magnetic pole pieces.

24. The particle accelerator of claim 23, further comprising:

a cryostat cover around at least part of the single structure and at least part of the magnetic pole pieces, the cryostat cover comprising a non-ferromagnetic material.

25. The particle accelerator of claim 14, which weighs less than 15 tons.

26. The particle accelerator of claim 14, which weighs less than 10 tons.

27. A proton therapy system comprising:

the particle accelerator of claim 14; and

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

wherein the proton therapy system is configured to output protons essentially directly from the particle accelerator to the patient position.