Electric field-guided particle accelerator, method, and applications
A charged particle accelerator having a curvilinear beam trajectory maintained solely by a laterally directed, constant electric field; requiring no magnetic field. A method for controlling the trajectory of a charged particle in an accelerator by applying only a constant electric field for beam trajectory control. Curvilinear steering electrodes held at a constant potential create the beam path. A method for making a chip-scale charged particle accelerator involves integrated circuit-based processes and materials. A particle accelerator that can generate 110 KeV may a footprint less than about 1 cm 2 .
1. A charged particle accelerator, comprising:
an accelerator support structure having a principal plane orientation;
a single pair of opposing, spaced, curvilinear steering electrodes disposed in the support structure having a gap there between, which define a particle pathway in the support structure, wherein the steering electrodes are characterized by an adjustable electric field;
a particle entry pathway in the support structure connected to the particle pathway; and
a pair of particle acceleration electrodes disposed in one of the entry pathway and the particle pathway.
2. The charged particle accelerator of claim 1 , wherein the steering electrodes are characterized by a constant electric field.
3. The charged particle accelerator of claim 1 , wherein the particle pathway has a maximum radius equal to or less than fifteen centimeters.
4. The charged particle accelerator of claim 1 , wherein the particle pathway has a maximum radius equal to or less than four centimeters.
5. The charged particle accelerator of claim 1 , wherein the particle pathway has a radius equal to or less than 1.0 centimeter.
6. The charged particle accelerator of claim 1 , further comprising a particle exit pathway in the support structure connected to the particle pathway.
7. The charged particle accelerator of claim 1 , wherein the curvilinear steering electrodes are disposed in a circle.
8. The charged particle accelerator of claim 1 , further wherein the support structure is disposed in an evacuable housing.
9. The charged particle accelerator of claim 1 , wherein the accelerator support structure is an integrated circuit-compatible substrate.
10. The charged particle accelerator of claim 1 , further comprising a magnetic lens disposed in the particle pathway.
11. The charged particle accelerator of claim 1 , wherein the particle pathway has a width between about 10 micrometers to about 100 micrometers.
12. The charged particle accelerator of claim 11 , wherein the particle pathway has a depth to width ratio greater than or equal to 1:1.
13. The charged particle accelerator of claim 11 , wherein the particle pathway has a depth to width ratio in the range between about 1:2 to 1:30.
14. The charged particle accelerator of claim 1 , further comprising a pair of DC guide electrodes disposed in the particle entry pathway.
15. The charged particle accelerator of claim 1 , wherein the particle acceleration electrodes are operatively characterized by an oscillating field.
16. The charged particle accelerator of claim 1 , further comprising a pair of opposing magnets, wherein the support structure is disposed between the magnets, further wherein the particle accelerator is characterized by a uniform magnetic field passing through the support structure normal to the principal plane orientation.
17. The charged particle accelerator of claim 1 , further comprising;
a plurality of pairs of opposing, spaced, curvilinear steering electrodes disposed in the support structure, each having a particle entry end and a particle exit end; and
a plurality of pairs of particle acceleration electrodes, each one of which is disposed intermediate an exit end of an n th steering electrode and an entry end of an n th +1 steering electrode.
18. The charged particle accelerator of claim 17 , wherein each of the plurality of steering electrodes is characterized by an adjustable, constant electric field.
19. The charged particle accelerator of claim 1 , further comprising;
a plurality of opposing, spaced, curvilinear steering electrodes disposed in the support structure, each having a different radius and a common particle entry/exit region; and
a single pair of particle acceleration electrodes disposed in the common particle entry/exit region.
20. The charged particle accelerator of claim 19 , wherein each of the plurality of steering electrodes is characterized by an adjustable, constant electric field.
21. The charged particle accelerator of claim 19 , wherein the plurality of curvilinear steering electrodes are circular.
22. The charged particle accelerator of claim 1 , further comprising;
a plurality of pairs of opposing, spaced, curvilinear steering electrodes disposed in the support structure, each having a particle entry end and a particle exit end, wherein the exit end of an n th steering electrode is aligned with the entry end of an n th +1 steering electrode; and
a plurality of pairs of particle acceleration electrodes, each one of which is disposed at the exit end of an n th steering electrode and the entry end of an n th +1 steering electrode.
23. The charged particle accelerator of claim 22 , wherein each of the plurality of steering electrodes is characterized by an adjustable, constant electric field.
24. The charged particle accelerator of claim 22 , wherein the plurality of curvilinear steering electrodes are circular.
25. The charged particle accelerator of claim 1 , further comprising a sensor adapted to measure a parameter of a bolus of charged particles traveling in the particle pathway.
26. The charged particle accelerator of claim 25 , wherein the sensor comprises a feedback control circuit.
27. A method for controlling the path of a charged particle in a particle accelerator, comprising:
providing a charged particle pathway defined by a gap between a pair of opposing, spaced, curvilinear steering electrodes in an accelerator structure;
inputting a traveling charged particle to an entry end of the pathway;
applying a constant voltage across the pair of steering electrodes so as to exert a constant, laterally-directed electric field on the charged particle traveling in the pathway; and
steering the traveling charged particle in a curvilinear trajectory having a maximum radius equal to or less than eight centimeters.
28. The method of claim 27 , further comprising providing a set of magnets so as to exert a constant, transversely-directed magnetic field on the charged particle traveling in the pathway.
29. A method for making a chip-scale particle accelerator, comprising:
providing an integrated circuit-compatible planar substrate;
providing an insulating material layer on a principal surface of the substrate;
providing an electrically conducting material layer on the layer of insulating material;
providing an electrical contact to the electrically conducting material layer; and
providing a curvilinear channel in the electrically conducting material layer.
30. The method of claim 29 , further comprising providing the curvilinear channel having a channel height to channel width ration equal to or greater than 1:1.