Compact accelerator

• US 7,173,385 B2
• Filed: 01/14/2005
• Issued: 02/06/2007
• Est. Priority Date: 01/15/2004
• Status: Active Grant

• Current Assignee: Lawrence Livermore National Security LLC (Government of the United States of America)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Caporaso, George J., Sampayan, Stephen E., Kirbie, Hugh C.
• Primary Examiner(s): Vo; Tuyet
• Assistant Examiner(s): VU, JIMMY T
• Application Number:
  US11/036,431
• Publication Number:
  US 20050184686A1
• Time in Patent Office: 753 Days
• Field of Search: 315/5.41, 315/5.42, 315/5.47, 315/500, 315/505, 315/507, 328/233
• US Class Current: 315/505
• CPC Class Codes: H05H 7/00 Details of devices of the types covered by groups H05H9/00, H05H11/00, H05H13/00
• CPC Class Codes: H05H 9/02 Travelling-wave linear accelerators travelling-wave tubes H01J25/34

Abstract

A compact linear accelerator having at least one strip-shaped Blumlein module which guides a propagating wavefront between first and second ends and controls the output pulse at the second end. Each Blumlein module has first, second, and third planar conductor strips, with a first dielectric strip between the first and second conductor strips, and a second dielectric strip between the second and third conductor strips. Additionally, the compact linear accelerator includes a high voltage power supply connected to charge the second conductor strip to a high potential, and a switch for switching the high potential in the second conductor strip to at least one of the first and third conductor strips so as to initiate a propagating reverse polarity wavefront(s) in the corresponding dielectric strip(s).

Claims

1. A compact linear accelerator, comprising:

a Blumlein module having;

a first planar conductor strip having a first end connected to a ground potential, and a second end adjacent an acceleration axis;

a second planar conductor strip adjacent to and parallel with the first planar conductor strip, said second planar conductor strip having a first end switchable between the ground potential and a high voltage potential and a second end adjacent the acceleration axis;

a third planar conductor strip adjacent to and parallel with the second planar conductor strip, said third planar conductor strip having a first end connected to a ground potential and a second end adjacent the acceleration axis;

a first dielectric strip that fills the space between the first and second planar conductor strips, and comprising a first dielectric material with a first dielectric constant; and

a second dielectric strip that fills the space between the second and third planar conductor strips, and comprising a second dielectric material with a second dielectric constant,

wherein the strip configuration of the Blumlein module guides an electrical signal wave propagated therethrough from the first end to the second end in order to control an output pulse produced at the second end.

2. The compact linear accelerator of claim 1, further comprising:

high voltage power supply means connected to charge said second planar conductor strip to a high potential; and

switching means for switching the high potential in the second planar conductor strip to at least one of the first and third planar conductor strips so as to initiate a propagating reverse polarity wavefront(s) in the corresponding dielectric strip(s).

3. The compact linear accelerator of claim 1,

wherein said Blumlein modules has a non-linear, strip-shaped configuration.

4. The compact linear accelerator of claim 1,

further comprising at least one additional Blumlein module stacked in alignment with the first module.

5. The compact linear accelerator of claim 1,

further comprising at least one additional Blumlein module, said modules perimetrically surrounding a segment of the acceleration axis, and with each perimetrically surrounding module connected to an associated switching means for initiating a propagating reverse polarity wavefront through the respective module.

6. The compact linear accelerator of claim 5,

further comprising at least one additional Blumlein module stacked in alignment with each of said perimetrically surrounding modules, whereby the additionally stacked modules perimetrically surround adjacent segments of the acceleration axis.

7. The compact linear accelerator of claim 5,

wherein said perimetrically surrounding modules each have a non-linear, strip-shaped configuration.

8. The compact linear accelerator of claim 5,

wherein the first, second, and third planar conductor strips of said perimetrically surrounding modules are connected to corresponding first, second, and third ring electrodes at the respective second ends thereof, said ring electrodes encircling the central region associated with said segment of the acceleration axis.

9. The compact linear accelerator of claim 8,

further comprising an insulator sleeve adjacent an inner diameter of said ring electrodes.

10. The compact linear accelerator of claim 8,

further comprising an insulator sleeve between said ring electrodes.

11. The compact linear accelerator of claim 1,

wherein said second planar conductor strip has a width, w₁, defined by the equation Z₁=k₁g₁(w₁,d₁), and the second dielectric strip has a thickness, d₂, defined by the equation Z₂=k₂g₂(w₂, d₂).

12. The compact linear accelerator of claim 11,

wherein Z₁ is substantially equivalent to Z₂.

13. The compact linear accelerator of claim 11,

wherein the width, w₁, of the second planar conductor strip is varied along a length, l, thereof, so as to control the output pulse shape.

14. The compact linear accelerator of claim 13,

wherein the width, w₁, of the second planar conductor strip narrows toward the second end thereof.

15. The compact linear accelerator of claim 13,

further comprising at least one additional Blumlein module stacked in alignment with the other Blumlein module.

16. The compact linear accelerator of claim 13,

further comprising at least one additional Blumlein module, said modules perimetrically surrounding a segment of the acceleration axis, and with each perimetrically surrounding module connected to an associated switching means for initiating a propagating reverse polarity wavefront through the respective module.

17. The compact linear accelerator of claim 16,

further comprising at least one additional Blumlein module stacked in alignment with each of said perimetrically surrounding modules, whereby the additionally stacked modules perimetrically surround adjacent segments of the acceleration axis.

18. The compact linear accelerator of claim 16,

wherein said perimetrically surrounding modules each have a non-linear, strip-shaped configuration.

19. The compact linear accelerator of claim 16,

wherein said perimetrically surrounding modules are connected to a ring electrode at respective second ends thereof, said ring electrode encircling the central region associated with said segment of the acceleration axis.

20. The compact linear accelerator of claim 19,

further comprising an insulator sleeve adjacent an inner diameter of said ring electrodes.

21. The compact linear accelerator of claim 19,

further comprising an insulator sleeve between the ring electrodes.

22. The compact linear accelerator of claim 1,

wherein at least one dielectric strip comprises a laminated structure having alternating layers of conductive and insulating foils.

23. The compact linear accelerator of claim 13,

wherein at least one dielectric strip comprises a laminated structure having alternating layers of conductive and insulating foils.

24. The compact linear accelerator of claim 1,

further comprising an electromagnetic material adjacent at least one dielectric strip so as to inhibit the propagation of the wavefront in said strip.

25. The compact linear accelerator of claim 13,

further comprising an electromagnetic material adjacent at least one dielectric strip so as to inhibit the propagation of the wavefront in said strip.

26. A compact linear accelerator, comprising:

a Blumlein module having;

a first planar conductor strip having a first end connected to a ground potential, and a second end adjacent an acceleration axis;

a second planar conductor strip adjacent to and parallel with the first planar conductor strip, said second planar conductor strip having a first end switchable between the ground potential and a high voltage potential and a second end adjacent the acceleration axis;

a third planar conductor strip adjacent to and parallel with the second planar conductor strip, said third planar conductor strip having a first end connected to a ground potential and a second end adjacent the acceleration axis;

a first dielectric strip that fills the space between the first and second planar conductor strips, and comprising a first dielectric material with a first dielectric constant; and

a second dielectric strip that fills the space between the second and third planar conductor strips, and comprising a second dielectric material with a second dielectric constant;

high voltage power supply means connected to charge said second planar conductor strip to a high potential; and

switching means for switching the high potential in the second planar conductor strip to at least one of the first and third planar conductor strips so as to initiate a propagating reverse polarity wavefront(s) in the corresponding dielectric strip(s),

wherein the strip configuration of the Blumlein module guides an electrical signal wave propagated therethrough from the first end to the second end in order to control an output pulse produced at the second end.