Compact Coherent X-Ray Source (CCXS)

Technology #14750

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FIG. 1 shows a compact coherent radiation source including an injector, a superconducting radiofrequency linear accelerator, an emittance exchange beamline, a coherent enhancement cavity, and an electron beam dump.FIG. 2 is a magnified photographic image of a tip array with 200-nm spacing and 80-nm gate apertures.  FIG. 3 shows a further magnified view of a double-gated tip, wherein the second gate provides focusing of each individual beamlet.FIG. 4 shows modeled electron beamlets from an 8×8 nanotip array at a focus gate.  FIG. 5 shows the electron beamlets of FIG. 4 downstream after focusing, wherein the electron beamlets are focused by individual microlenses that do not change the spacing between beamlets.FIG. 6 shows an emittance exchange beamline including two dogleg bending lines separated by a deflecting radiofrequency cavity. Each dogleg includes two dipole magnets of opposite polarity separated by a drift space.
Professor Franz Kaertner
Research Laboratory of Electronics, MIT
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William Graves
Nuclear Reactor Laboratory, MIT
Professor David Moncton
Nuclear Reactor Laboratory, MIT
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Jim Freedman
MIT Technology Licensing Officer - Chemicals, Instruments, Consumer Products
Patent Protection

Compact coherent current and radiation source

US Patent 8,787,529

This invention consists of a high performance compact coherent x-ray source.


This invention has a broad suite of applications in the industrial, scientific, military and medical fields. Specific uses includes EUV lithography, x-ray microscopy, protein crystallography, and studies of ultrafast phenomena. 

Problem Addressed

Current methods of x-ray generation includes bremsstrahlung x-rays from a tube, inverse compton scattering in either a small linear accelerator or via synchrotrons and x-ray free electron lasers. These methods are either non-coherent, inefficient or too expensive. Therefore, there is a need for a high performance x-ray source that is coherent, inexpensive and efficient.


The invention emits coherent radiation by first generating and transmitting an array of discrete electron beamlets from a nanocathode array along a longitudinal axis. Subsequently, an array of electron beamlets is focused to reduce the spacing that separates the electron beamlets. The transverse-axis spacing of the electron beamlets is then transferred to the longitudinal axis via an emittance exchange beamline, creating a periodically modulated distribution of coherent electronic current. The coherent electronic current can then be directed into a stream of photons to generate coherent x-ray radiation.


  • The invention uses reduced electron energy, thus it is smaller in size and cheaper than current x-ray generation methods.
  • It can generate high performance x-rays similar to those produced by large synchrotron facilities and FELs.
  • It has improved spatial resolution over conventional radiography.