Electron cooling system and method for increasing the phase space intensity and overall intensity of ion beams in multiple overlap regions

8,063,390

12/716477

March 03, 2010

An electron cooling system and method for increasing the phase space intensity and overall intensity of ion beams in multiple overlap regions, including a vacuum chamber to allow a single electron beam to be merged and separated with multiple ion beams, an electron supply device including a cathode to generate the electron beam, an electron collector device including a collection plate to collect the electron beam, multiple magnetic field generation devices to guide the electrons on their desired trajectories, and multiple electrodes to set the velocity of the electron beam independently in each overlap region. By overlapping the electron and ion beams, thermal energy is transferred from the ion beams to the electron beam, which allows an increase in the phase space density and overall density of the ion beams. Advantageously, the electron cooling system uses multiple magnetic field generation devices to guide the electrons into and out of multiple, separate, ion beam overlap regions, allowing the single electron beam to cool an ion beam in more than one overlap region. Advantageously, the electron cooling system uses electrodes to control the mean electron beam velocity in each overlap region, allowing for mitigation of electron beam emittance growth caused by scattering that occurs exterior to the overlap regions. Advantageously, the electrodes used to control the mean electron beam velocity in each overlap region allow for a single electron beam to achieve different velocities to match different desired ion beam velocities in the multiple overlap regions.

Larson, Delbert J. (Waxahachie, TX, US)

1. An electron beam and ion beam system including an electron beam, a first ion beam, and a second ion beam, comprising: a vacuum chamber to allow passage, merging and separation of said electron beam and said first ion beam including a first overlap region wherein said electron beam and said first ion beam are overlapped, and to allow passage, merging and separation of said electron beam and said second ion beam including a second overlap region wherein said electron beam and said second ion beam are overlapped; an electron supply device including a cathode to produce said electron beam; an electron collector including a collection plate to collect said electron beam; a first electrode located proximate to said first overlap region and biased at a potential to set the velocity of said electron beam to the desired velocity of said first ion beam; a second electrode located proximate to said second overlap region and biased at a potential to set the velocity of said electron beam to the desired velocity of said second ion beam; a first magnetic field production device to create magnetic fields to guide said electron beam along a desired path, merge and separate said electron beam and said first ion beam; a second magnetic field production device to create magnetic fields to guide said electron beam along a desired path, merge and separate said electron beam and said second ion beam.

2. A system in accordance with claim 1 , wherein at least one of said first electrode or said second electrode includes a substantially central opening to allow passage of said electron beam and to allow passage of at least one of said first ion beam or said second ion beam.

3. A system in accordance with claim 1 , wherein at least one of said first electrode or said second electrode includes a grid conducting structure to allow passage of said electron beam and a separate substantially central opening to allow passage of at least one of said first ion beam or said second ion beam.

4. A system in accordance with claim 1 , wherein at least one of said first electrode or said second electrode is said vacuum chamber.

5. A system in accordance with claim 1 , wherein at least one of said first magnetic field production device or said second magnetic field production device includes solenoidal and torroidal wire windings with electric current flowing through the wires.

6. A system in accordance with claim 1 , wherein at least one of said first magnetic field production device or said second magnetic field production device includes solenoidal and torroidal wire windings with electric current flowing through the wires and permanent magnet material.

7. A system in accordance with claim 1 , wherein said first ion beam is the same beam as said second ion beam.

8. A system in accordance with claim 1 , wherein said first ion beam is a different beam than said second ion beam.

9. A method of cooling a first ion beam and a second ion beam with an electron beam comprising the steps of: operating a vacuum chamber to allow passage, merging and separation of said electron beam and said first ion beam including a first overlap region wherein said electron beam and said first ion beam are overlapped, and to allow passage, merging and separation of said electron beam and said second ion beam including a second overlap region wherein said electron beam and said second ion beam are overlapped; operating an electron supply device including a cathode to produce said electron beam; operating an electron collector including a collection plate to collect said electron beam; operating a first electrode located proximate to said first overlap region and biased at a potential to set the velocity of said electron beam to the desired velocity of said first ion beam; operating a second electrode located proximate to said second overlap region and biased at a potential to set the velocity of said electron beam to the desired velocity of said second ion beam; operating a first magnetic field production device to create magnetic fields to guide said electron beam along a desired path, merge and separate said electron beam and said first ion beam; operating a second magnetic field production device to create magnetic fields to guide said electron beam along a desired path, merge and separate said electron beam and said second ion beam.

10. A method in accordance with claim 9 , wherein at least one of said first electrode or said second electrode includes a substantially central opening to allow passage of said electron beam and to allow passage of at least one of said first ion beam or said second ion beam.

11. A method in accordance with claim 9 , wherein at least one of said first electrode or said second electrode includes a grid conducting structure to allow passage of said electron beam and a separate substantially central opening to allow passage of at least one of said first ion beam or said second ion beam.

12. A method in accordance with claim 9 , wherein at least one of said first electrode or said second electrode is said vacuum chamber.

13. A method in accordance with claim 9 , wherein at least one of said first magnetic field production device or said second magnetic field production device includes solenoidal and torroidal wire windings with electric current flowing through the wires.

14. A method in accordance with claim 9 , wherein at least one of said first magnetic field production device or said second magnetic field production device includes solenoidal and torroidal wire windings with electric current flowing through the wires and permanent magnet material.

15. A method in accordance with claim 9 , wherein said first ion beam is the same beam as said second ion beam.

16. A method in accordance with claim 9 , wherein said first ion beam is a different beam than said second ion beam.

2504/923

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