Next Generation X-Ray Lightsource and First Applications
Technical Report,15 Mar 2015,14 Mar 2019
University of Nebraska Lincoln United States
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During the period of this grant we have investigated and developed two sources for generating highly brilliant X-ray radiation from a comparably compact setup. The sources are based on the emission of synchrotron radiation from ultrashort relativistic electron bunches that are generated through high-intensity laser-plasma interactions, namely laser-wakefield acceleration. The developed sources include i a setup, where the radiation is generated by an external permanent magnet undulator and ii a source, where the radiation is generated by transverse betatron oscillations of the electron beam during the plasma acceleration process itself. The undulator-based source is capable of generating narrow-band radiation, which for current parameters of laser-wakefield accelerated electron beams emit at soft X-ray wavelengths. In particular, we have observed radiation at a photon energy around 300 eV from electron beams with an energy of 350 MeV. To this end, we have developed an ultrafast X-ray beamline that includes a compact electron transport system based on miniature quadrupole magnets, a home-built undulator with one the shortest periods of only 5 mm for permanent magnet undulator published to date, and electron beam and X-ray diagnostics. Our betatron-based source generates polychromatic radiation that extends from the soft X-ray 2 keV into the hard X-ray range 30 keV. In particular, within this grant period, we have demonstrated a novel method of enhancing and controlling laser-driven betatron radiation that has led to an increase of more than one order of magnitude in the number of generated photons compared to previous methods using the same laser parameters. We expect that the method has the potential to lead to further significant enhancements. We also showed that the method allows us to control the X-ray beam parameters.
- Nuclear Physics and Elementary Particle Physics
- Particle Accelerators