Laser-wakefield accelerators (LWFAs) are high acceleration-gradient plasma-based particle accelerators capable of producing ultra-relativistic electron beams. Within the strong focusing fields of the wakefield, accelerated electrons undergo betatron oscillations, emitting a bright pulse of X-rays with a micrometer-scale source size that may be used for imaging applications. Non-destructive X-ray phase contrast imaging and tomography of heterogeneous materials can provide insight into their processing, structure, and performance. To demonstrate the imaging capability of X-rays from an LWFA we have examined an irregular eutectic in the aluminum-silicon (Al-Si) system. The lamellar spacing of the Al-Si eutectic microstructure is on the order of a few micrometers, thus requiring high spatial resolution. We present comparisons between the sharpness and spatial resolution in phase contrast images of this eutectic alloy obtained via X-ray phase contrast imaging at the Swiss Light Source (SLS) synchrotron and X-ray projection microscopy via an LWFA source. An upper bound on the resolving power of 2.7 ± 0.3 μm of the LWFA source in this experiment was measured. These results indicate that betatron X-rays from laser wakefield acceleration can provide an alternative to conventional synchrotron sources for high resolution imaging of eutectics and, more broadly, complex microstructures.

Center for Ultrafast Optical Science University of Michigan Ann Arbor MI 48109 2099 USA

Central Laser Facility STFC Rutherford Appleton Laboratory Didcot OX11 0QX UK

Department of Materials Science and Engineering University of Michigan Ann Arbor MI 48109 2099 USA

Department of Physics Lund University P O Box 118 S 22100 Lund Sweden

Diamond Light Source Harwell Science and Innovation Campus Fermi Avenue Didcot OX11 0DE UK

ELI Beamlines Institute of Physics of the ASCR 182 21 Prague Czech Republic

GoLP Instituto de Plasmas e Fusão Nuclear Instituto Superior Técnico U L Lisboa 1049 001 Portugal

Helmholtz Zentrum Dresden Rossendorf Bautzner Landstraße 400 01328 Dresden Germany

Institute of Physics of the ASCR 182 21 Prague Czech Republic

Lawrence Livermore National Laboratory NIF and Photon Sciences Livermore CA 94550 USA

Physics Department Lancaster University Lancaster LA1 4YB UK

SUPA Department of Physics University of Strathclyde Glasgow G4 0NG UK

Swiss Light Source Paul Scherrer Institute CH 5232 Villigen Switzerland

Technische Universität Dresden 01062 Dresden Germany

The Cockcroft Institute Keckwick Lane Daresbury WA4 4AD UK

The John Adams Institute for Accelerator Science Imperial College London London SW7 2AZ UK

York Plasma Institute Department of Physics University of York York YO10 5DD UK

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Sci Rep. 2020 Jan 10;10(1):320. doi: 10.1038/s41598-019-55304-6. PubMed

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