Modulated method for efficient, narrow-bandwidth, laser Compton X-ray and gamma-ray sources

Patent metadata

Field	Value
Publication number	US-9706631-B2
Application number	US-201414274348-A
Country	US
Kind code	B2
Filing date	May 9, 2014
Priority date	May 10, 2013
Publication date	Jul 11, 2017
Grant date	Jul 11, 2017

Abstract

A method of x-ray and gamma-ray generation via laser Compton scattering uses the interaction of a specially-formatted, highly modulated, long duration, laser pulse with a high-frequency train of high-brightness electron bunches to both create narrow bandwidth x-ray and gamma-ray sources and significantly increase the laser to Compton photon conversion efficiency.

First claim

I claim:

1. A method for generating x-rays or gamma rays via laser Compton scattering, comprising:
producing a continuous wave (CW) laser beam;
modulating said CW laser beam at a multi-GHz radio frequency (RF) to produce a modulated beam;
utilizing said modulated beam to provide electron micro bunches at said radio frequency (RF), wherein said RF is the operating RF of a linear accelerator that provides said bunches, wherein said bunches are directed to propagate, with radio frequency spacing between successive said bunches, within a first confocal region, wherein said first confocal region is produced by focusing said electron micro bunches; and
utilizing said modulated beam to provide laser pulses at said RF, wherein each laser pulse of said laser pulses has a pulse duration within the range of 10 ps to 1 fs, wherein said pulses are directed to propagate, with radio frequency spacing between successive said pulses, within a second confocal region, wherein said second confocal region is produced by focusing said laser pulses, wherein said first confocal region and said second confocal region intersect in an interaction region such that said electron micro bunches collide with said laser pulses to generate incoherent x-rays or gamma-rays via laser Compton scattering, wherein the pulse duration of each laser pulse of said laser pulses is of the order of the transit time of each laser pulse through said second confocal region and wherein the pulse duration of each electron micro bunch of said electron micro bunches is of the order of the transit time of each laser pulse of said laser pulses through said second confocal region.

2. The method of claim 1 , wherein each single laser pulse of said laser pulses collides with a single electron micro bunch of said electron micro bunches in said interaction region.

3. The method of claim 1 , wherein each single laser pulse of said laser pulses collides with a single electron, micro bunch of said electron micro bunches in said interaction region in a manner such that to first order each electron bunch and laser pulse pair produces the same number of laser Compton photons.

4. The method of claim 1 , wherein the bandwidth of a portion of said modulated beam has been increased via self-phase self modulation.

5. The method of claim 1 , wherein said said CW laser beam is an infrared CW laser beam, wherein the laser pulse spacing and the electron bunch spacing are matched.

6. The method of claim 1 , wherein the laser pulse spacing and the electron bunch spacing are matched.

7. The method of claim 1 , wherein the angle between said first confocal region and said second confocal region is about 90 degrees.

8. The method of claim 1 , wherein the angle between said first confocal region and said second confocal region is less than 180 degrees such that said electron micro bunches miss the optic that focuses said laser pulses.

9. A method for generating x-rays or gamma rays via laser Compton scattering, comprising:
producing a first CW laser beam;
modulating said first CW laser beam at a multi-GHz radio frequency (RF) to produce a first modulated beam; and
producing a second CW laser beam;
modulating said second CW laser beam at said multi-GHz RF to produce a second modulated beam;
utilizing said first modulated beam to provide electron micro bunches at said multi-GHz RF, wherein said RF is the operating RF of a linear accelerator that provides said bunches, wherein said bunches are directed to propagate, with radio frequency spacing between successive said bunches, within a first confocal region, wherein said first confocal region is produced by focusing said electron micro bunches; and
utilizing said second modulated beam to provide laser pulses at said RF, wherein each laser pulse of said laser pulses has a pulse duration within the range of 10 ps to 1 fs, wherein said pulses are directed to propagate, with radio frequency spacing between successive said pulses within a second confocal region, wherein said second confocal region is produced by focusing said laser pulses, wherein said first confocal region and said second confocal region intersect in an interaction region such that said electron micro bunches collide with said laser pulses to generate incoherent x-rays or gamma-rays via laser Compton scattering, wherein the pulse duration of each laser pulse of said laser pulses is of the order of the transit time of each laser pulse through said second confocal region and wherein the pulse duration of each electron micro bunch of said electron micro bunches is of the order of the transit time of each laser pulse of said laser pulses through said second confocal region.

10. The method of claim 9 , wherein the bandwidth of the individual pulse of said first modulated beam and said second modulated beam has been increased via self-phase modulation.

11. An apparatus for generating x-rays or gamma rays via laser Compton scattering, comprising:
a continuous wave (CW) laser for producing a CW laser beam;
a modulator configured for modulating said CW laser beam at a multi-GHz radio frequency (RF) to produce a modulated beam;
a linear accelerator comprising an electron gun, wherein said modulated beam is utilized to trigger said electron gun, wherein said linear accelerator is configured to provide electron micro bunches at said multi-GHz RF;
means for directing said electron micro bunches to propagate, with radio frequency spacing between successive said bunches, within a first confocal region, wherein said first confocal region is produced by focusing said electron micro bunches;
at least one source of laser pulses, wherein said at least one source is configured to utilize said modulated beam to provide said laser pulses at said multi-GHz RF, wherein each laser pulse of said laser pulses has a pulse duration within the range of 10 ps to 1 fs; and
means for directing said pulses so that they propagate, with radio frequency spacing between successive said pulses, within a second confocal region, wherein said second confocal region is produced by focusing said laser pulses, wherein said first confocal region and said second confocal region intersect in an interaction region such that said electron micro bunches will collide with said laser pulses to generate incoherent x-rays or gamma-rays via laser Compton scattering, wherein the pulse duration of each laser pulse of said laser pulses is of the order of the transit time of each laser pulse through said second confocal region and wherein the pulse duration of each electron micro bunch of said electron micro bunches is of the order of the transit time of each laser pulse of said laser pulses through said second confocal region.

12. The apparatus of claim 11 , wherein each single laser pulse of said laser pulses collides with a corresponding single electron micro bunch of said electron micro bunches in said interaction region.

13. The apparatus of claim 11 , wherein each single laser pulse of said laser pulses collides with a corresponding single electron micro bunch of said electron micro bunches in said interaction region in a manner such that to first order each electron bunch and laser pulse pair produces the same number of laser Compton photons.

14. The apparatus of claim 11 , wherein said CW laser beam comprises a CW infrared laser beam.

15. The apparatus of claim 14 , further comprising at least one means for increasing, via self-phase modulation, the bandwidth of a portion of said at least one modulated beam.

16. The apparatus of claim 11 , wherein the angle between said first confocal region and said second confocal

Assignees

• L Livermore Nat Security Llc

Inventors

• Barty Christopher P J

Classifications

• H05G2/00 Primary

  Apparatus or processes specially adapted for producing X-rays, not involving X-ray tubes, e.g. involving generation of a plasma (X-ray lasers H01S4/00) · CPC title