Coherent electron and radiation production using transverse spatial modulation and axial transfer

Patent metadata

Field	Value
Publication number	US-9697924-B2
Application number	US-201514674482-A
Country	US
Kind code	B2
Filing date	Mar 31, 2015
Priority date	Apr 1, 2014
Publication date	Jul 4, 2017
Grant date	Jul 4, 2017

Abstract

Coherent electronic current is generated by generating and transmitting an electron bunch along a longitudinal axis. The electron bunch is then directed onto a target, wherein the target imparts a transverse spatial modulation to the electron bunch via diffraction contrast or phase contrast. The transverse spatial modulation of the electron bunch is then transferred to the longitudinal axis via an emittance exchange beamline, creating a periodically modulated distribution of coherent electronic current.

First claim

What is claimed is:

1. A method for generating coherent electron current comprising:
generating and transmitting an electron bunch along a longitudinal axis;
directing the electron bunch onto a target, wherein the target imparts a transverse spatial modulation to the electron bunch via at least one of diffraction contrast and phase contrast, and wherein the transverse spatial modulation is orthogonal to the longitudinal axis; and
transferring the transverse spatial modulation of the electron bunch to the longitudinal axis via an emittance exchange beamline, creating a periodically modulated distribution of coherent electron current along the longitudinal axis.

2. The method of claim 1 , further comprising directing the periodically modulated distribution of electron current into a stream of photons to generate coherent radiation.

3. The method of claim 2 , wherein the stream of photons have a periodic distribution matching that of the electron current.

4. The method of claim 2 , wherein the coherent radiation is generated by inverse Compton scattering of the electrons on a laser pulse.

5. The method of claim 1 , further comprising directing the periodically modulated distribution of electron current into a static magnetic field to generate coherent radiation.

6. The method of claim 5 , wherein the coherent radiation is generated in a magnetic undulator.

7. The method of claim 5 , wherein the coherent radiation is generated in a dipole magnetic field.

8. The method of claim 1 , further comprising accelerating the periodically modulated distribution of coherent electron current.

9. The method of claim 8 , wherein the periodically modulated distribution of coherent electron current is accelerated without using a superconducting material.

10. The method of claim 1 , wherein the target is a crystal lattice, and wherein the transverse spatial modulation is imparted via phase contrast.

11. The method of claim 10 , wherein the crystal lattice has an atomic spacing less than 1 nm.

12. The method of claim 10 , wherein the crystal lattice comprises a crystalline material selected from silicon and carbon.

13. The method of claim 1 , wherein the target is a grating, and wherein the transverse spatial modulation is imparted via diffraction contrast.

14. The method of claim 13 , wherein the grating has a spacing no greater than about 1,000 nm.

15. The method of claim 13 , wherein the grating comprises silicon or carbon.

16. The method of claim 1 , further comprising at least one of (a) focusing and (b) magnifying the electron bunch before transferring the transverse spatial modulation of the electron bunch to the longitudinal axis.

17. The method of claim 16 , further comprising using solenoid magnets and quadrupole magnets to achieve the at least one of (a) focusing ad (b) magnifying the electron bunch.

18. The method of claim 1 , wherein the electron bunch is generated by directing photons from a laser onto a cathode.

19. The method of claim 1 , wherein the electron bunch is provided by a terahertz acceleration structure.

20. An apparatus for generating coherent electron current comprising:
an electron source configured to emit an electron bunch along a longitudinal axis;
at least one magnet structure selected from a solenoid and quadrupole magnets positioned to receive and to at least one of (a) focus and (b) magnify the electron bunch;
a target positioned to receive the electron bunch from the magnet structure, wherein the target imparts a transverse spatial modulation to the electron bunch via at least one of diffraction contrast and phase contrast; and
an emittance exchange beamline positioned and configured to convert a transverse structure of the electron bunch to a longitudinal structure along the longitudinal axis to produce a periodically modulated distribution of coherent electron current.

21. The apparatus of claim 20 , further comprising:
an enhancement cavity including optical elements that define an optical path in the enhancement cavity, wherein the enhancement cavity is positioned to receive the periodically modulated distribution of coherent electron current; and
a laser positioned and configured to generate photons and to direct the photons into the enhancement cavity for circulation along the optical path in the enhancement cavity where the photons can interact with the periodically modulated distribution of coherent electron current to generate radiation.

22. The apparatus of claim 20 , further comprising an accelerator positioned and configured to receive and accelerate the electron bunch, after the transverse spatial modulation, along the longitudinal axis.

Assignees

• Massachusetts Inst Technology

Inventors

• Nanni Emilio Alessandro
• Graves William Sproull
• Kaertner Franz Xaver
• Moncton David Eugene

Classifications

• G21K1/06

  using diffraction, refraction or reflection, e.g. monochromators (G21K1/10, G21K7/00 take precedence) · CPC title

• G21K5/00 Primary

  Irradiation devices (discharge tubes for irradiating H01J37/00) · CPC title

• H01J23/18 Primary

  Resonators · CPC title

• H05G2/00

  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