MAGNETIC FIELD CONTROL METHOD AND APPARATUS USED IN CONJUNCTION WITH A CHARGED PARTICLE CANCER THERAPY SYSTEM

• US 20090309520A1
• Filed: 08/22/2009
• Published: 12/17/2009
• Est. Priority Date: 05/22/2008
• Status: Active Grant

• Current Assignee: Andrey Vladimirovich Balakin, Pavel Vladimirovich Balakin
• Original Assignee: Vladimir Balakin
• Inventors: Balakin, Vladimir
• Granted Patent: US 8,188,688 B2
• Time in Patent Office: Days
• US Class Current: 315/503
• CPC Class Codes: H05H 13/04 Synchrotrons
• CPC Class Codes: H05H 7/04 Magnet systems , e.g. undulators, wigglers free-electron laser H01S3/0903; Energisation thereof

Abstract

The invention comprises a charged particle beam acceleration, extraction, and/or targeting method and apparatus used in conjunction with charged particle beam radiation therapy of cancerous tumors. Novel design features of a synchrotron are described. Particularly, turning magnets, edge focusing magnets, concentrating magnetic field magnets, winding and control coils, flat surface incident magnetic field surfaces, and extraction elements are described that minimize the overall size of the synchrotron, provide a tightly controlled proton beam, directly reduce the size of required magnetic fields, directly reduces required operating power, and allow continual acceleration of protons in a synchrotron even during a process of extracting protons from the synchrotron.

Claims

1. An apparatus for acceleration of charged particles in a charged particle beam path, comprising:

a synchrotron, said synchrotron comprising;

a first magnet, said first magnet comprising an incident surface;

a non-magnetic isolating layer, said isolating layer comprising a first side and a second side;

a first magnetic penetration layer, said first magnetic penetration layer comprising a first foil, said first foil comprising an inner surface and an outer surface; and

a second magnet, said second magnet comprising an exiting surface, said incident surface of said first magnet affixed to said first side of said isolating layer, said second side of said isolating layer affixed to said inner surface of said first foil, said charged particle beam path positioned between said outer surface of said first foil and said exiting surface.

2. The apparatus of claim 1, said synchrotron further comprising:

a second magnetic penetration layer, said second magnetic penetration layer comprising a second foil, said second foil comprising an inner side and an outer side, said inner side of said second foil affixed to said outer surface of said first foil.

3. The apparatus of claim 2, wherein both said first foil and said second foil each comprise a thickness of less than about 0.2 millimeters, wherein all of said first foil inner surface, said first foil outer surface, said second foil inner side, and said second foil outer side comprise a surface finish of less than about five micron polish.

4. The apparatus of claim 2, said synchrotron further comprising:

a return yoke, wherein a magnetic field runs sequentially through said first magnet, said non-conductive isolating layer, said first magnetic penetration layer, said second magnetic penetration layer, said charged particle beam path, said second magnet, said yoke, and back to said first magnet.

5. The apparatus of claim 1, wherein said charged particle beam path comprises a vacuum path with cross dimensions of less than about three centimeters by about eight centimeters.

6. The apparatus of claim 1, wherein said isolating layer comprises a non-conductive material, wherein said isolating material comprises a thickness of less than about one millimeter.

7. The apparatus of claim 1, wherein the charged particles circulate in said charged particle beam path during use.

8. The apparatus of claim 1, wherein said synchrotron further comprises:

a radio-frequency cavity system comprising a first pair of blades for inducing betatron oscillation of the charged particles;

an extraction foil yielding slowed charged particles from the charged particles having sufficient betatron oscillation to traverse said foil, wherein the slowed charged particles pass through a second pair of blades having an extraction voltage directing the charged particles out of said synchrotron through an extraction magnet.

9. A method for turning charged particles in a charged particle beam path, comprising the step of:

accelerating the charged particles with a synchrotron, said synchrotron comprising;

a first magnet generating a magnetic field, said first magnet comprising an incident surface;

a non-magnetic isolating layer, said isolating layer comprising a first side and a second side, said non-magnetic isolating layer comprising a thickness of at least 0.05 millimeters;

a first magnetic penetration layer, said first magnetic penetration layer comprising a first foil, said first foil comprising an inner surface and an outer surface;

a second magnet, said second magnet comprising an exiting surface, said incident surface of said first magnet affixed to said first side of said isolating layer, said second side of said isolating layer affixed to said inner surface of said first foil, said charged particle beam path positioned between said outer surface of said first foil and said exiting surface; and

generating a magnetic field using said first magnet; and

blending said magnetic field using said thickness of said non-magnetic isolating layer provides to even out non-uniform properties of said magnetic field, wherein said magnetic field turns said charged particles in said charged particle beam path.

10. The method of claim 9, further comprising the step of:

evening said magnetic field using a second magnetic penetration layer, said second magnetic penetration layer comprising a second foil, said second foil comprising an inner side and an outer side, said inner side of said second foil affixed to said outer surface of said first foil, wherein a surface polish of said outer side of said second foil evens said magnetic field.

11. The method of claim 10, wherein both said first foil and said second foil each comprise a thickness of less than about 0.2 millimeters, wherein all of said first foil inner surface, said first foil outer surface, said second foil inner side, and said second foil outer side comprise a surface finish of less than about five micron polish.

12. The method of claim 10, further comprising the step of:

circulating said magnetic field sequentially through said first magnet, said non-conductive isolating layer, said first magnetic penetration layer, said second magnetic penetration layer, said charged particle beam path, said second magnet, said yoke, and back to said first magnet.

13. The method of claim 9, further comprising the step of:

circulating said charged particles in said charged particle beam path, wherein said magnetic field axially crosses said charged particle beam path.

14. The method of claim 9, further comprising the steps of:

inducing a betatron oscillation of the charged particles using a radio-frequency cavity system comprising a first pair of blades;

traversing the charged particles across an extraction foil yielding slowed charged particles from the charged particles having sufficient betatron oscillation to traverse said foil;

passing the slowed charged particles through a second pair of blades having an extraction voltage; and

extracting the charged particles passing through said second pair of blades out of said synchrotron through an extraction magnet.

15. The method of claim 9, further comprising the steps of:

controlling a magnetic field in a bending magnet of said synchrotron, said bending magnet comprising;

a tapered iron based core adjacent said charged particle beam path, said core comprising a surface polish of less than about ten microns roughness; and

a focusing geometry comprising;

a first cross-sectional distance of said iron based core forming an edge of said first magnet; and

a second cross-sectional distance of said iron based core not in contact with said charged particle beam path, wherein said second cross-sectional distance is at least fifty percent larger than said first cross-sectional distance, said first cross-sectional distance running parallel said second cross-sectional distance.

16. The method of claim 9, further comprising the steps of:

extracting the charged particles from said synchrotron;

controlling an energy of the charged particles; and

controlling an intensity of the charged particles,

wherein said step of controlling said energy and said step of controlling said intensity both occur prior to the charged particles passing through a Lamberson extraction magnet in said synchrotron during said step of extracting.

17. The method of claim 9, further comprising the steps of:

rotating a platform, said charged particle beam path passing above at least a portion of said platform, wherein said platform rotates through at least one hundred eighty degrees during an irradiation period; and

delivering the charged particles above said platform in said charged particle beam path, wherein said step of delivering the charged particles occurs in greater than four rotation positions of said rotatable platform.

18. The method of claim 9, further comprising the steps of:

transmitting the circulating charged particle beam through an extraction material, said extraction material yielding a reduced energy charged particle beam;

applying a field of at least five hundred volts across a pair of extraction blades;

passing the reduced energy charged particle beam between said pair of extraction blades,

wherein said field redirects the reduced energy charged particle beam as an extracted charged particle beam.

19. An apparatus for acceleration of charged particles in a charged particle beam path, comprising:

a synchrotron, said synchrotron comprising;

a first magnet, said first magnet comprising an incident surface; and

a first foil, said first foil comprising an inner side and an outer side, said inner side of said first foil affixed with a first adhesive layer to said incident surface, said charged particle beam path proximate said outer side of said foil.

20. The apparatus of claim 19, wherein said first foil of said first magnetic penetration layer comprises a thickness of less than about 0.2 mm thickness, wherein both said inner side of said foil and said outer side of said foil comprise an average surface roughness of less than about three micrometers.

21. The apparatus of claim 19, wherein said first foil comprises a nickel alloy.

22. The apparatus of claim 20, further comprising a gap isolating material, wherein said gap isolating layer comprises a non-conductive electric isolating layer, wherein said gap isolating material comprises a non-magnetic material, wherein said gap isolating material comprises an outer surface finish of about zero to three microns, said gap isolating material positioned between said incident surface of said first magnet and said inner side of said first foil.

23. The apparatus of claim 22, further comprising:

a second foil, said second foil comprising a first side and a second side, said first side of said second foil affixed to said outer side of said first foil with a second adhesive layer.

24. The apparatus of claim 19, further comprising:

a second magnet, said second magnet comprising an exiting surface,

wherein said charged particle beam path is positioned between said outer side of said first foil and said second magnet.

25. The apparatus of claim 19, wherein said synchrotron further comprises:

exactly four ninety degree turning sections, wherein each of said four ninety degree turning sections further comprises at least four magnets proximate said charged particle beam path, said at least four magnets comprising a total of at least eight beveled focusing edges.

26. The apparatus of claim 19, said synchrotron further comprising:

an extraction material;

at least a one kilovolt direct current field applied across a pair of extraction blades; and

a deflector,

wherein the charged particles beam pass through said extraction material resulting in a reduced energy charged particle beam,

wherein the reduced energy charged particle beam passes between said pair of extraction blades, and

wherein the direct current field redirects the reduced energy charged particle beam through said deflector,

wherein said deflector yields an extracted charged particle beam.

27. An apparatus for acceleration of charged particles in a charged particle beam path, comprising:

a pair of magnets;

a first foil magnetic penetration layer, said foil magnetic penetration layer less than about one-tenth of a millimeter thickness, said penetration layer comprising a first side and a second side, said second side of said foil comprising a surface roughness of less than about three microns; and

said charged particle beam path running through a gap between said pair of magnets,

wherein a first magnet of said pair of magnets comprises a gap surface, said gap surface coplanar with said first side of said foil, said second side of said foil proximate said gap.

28. The apparatus of claim 27, further comprising a non-magnetic isolating layer, said isolating layer comprising a thickness of at least about 0.05 mm and less than about 0.5 mm, said isolating layer comprising a first side and a second side;

said isolating layer separating said gap surface from said first side of said foil.

29. The apparatus of claim 27, further comprising a synchrotron using said pair of magnets in acceleration of the charged particles, said synchrotron further comprising:

an extraction material;

at least a one kilovolt direct current field applied across a pair of extraction blades; and

a deflector,

wherein the charged particles pass through said extraction material resulting in a reduced energy charged particle beam,

wherein the reduced energy charged particle beam passes between said pair of extraction blades, and

wherein the direct current field redirects the reduced energy charged particle beam through said deflector,

wherein said deflector yields an extracted charged particle beam.

30. The apparatus of claim 27, further comprising a synchrotron using said pair of magnets in acceleration of the charged particles, said synchrotron further comprising:

multi-axis control, said multi-axis control comprising control of;

an energy; and

an intensity; and

a rotatable platform,

wherein said control of said energy and said control of said intensity occurs during extraction,

wherein said rotatable platform rotates through at least one hundred eighty degrees during an irradiation period,

wherein said multi-axis control operates during at least ten rotation positions of said rotatable platform.

31. The apparatus of claim 30, wherein said multi-axis control further comprises independent control of all of:

a horizontal position of the charged particles;

a vertical position of the charged particles;

said energy; and

said intensity, wherein said multi-axis control comprises delivery of the charged particles during said at least ten rotation positions of said rotatable platform.

32. An apparatus for providing a uniform magnetic field, comprising:

a first magnet, said first magnet comprising an incident surface;

a non-magnetic isolating layer, said isolating layer comprising a thickness of at least about 0.05 mm and less than about one-half millimeter, said isolating layer comprising a first side and a second side;

a magnetic penetration layer, said magnetic penetration layer comprising an inner surface and an outer surface, said incident surface of said first magnet affixed to said first side of said isolating layer, said second side of said isolating layer affixed to said inner surface of said magnetic penetration layer,

wherein said thickness of said non-magnetic isolating layer provides a distance to even out and blend non-uniform properties of said first magnet,

wherein said surface polish of said foil yields the uniform magnetic field.

33. The apparatus of claim 32, wherein said first magnet comprises a substantially iron core, wherein and said magnetic penetration layer comprises a nickel alloy.

34. The apparatus of claim 32, wherein said incident surface of said first magnet comprises a surface roughness greater than a surface roughness of said outer surface of said magnetic penetration layer.