Profiling structured beams using injected aerosols

N. D. Loh, Dmitri Starodub, Lukas Lomb, Christina Y. Hampton, Andrew V. Martin, Raymond G. Sierra, Anton Barty, Andrew Aquila, Joachim Schulz, Jan Steinbrener, Robert L. Shoeman, Stephan Kassemeyer (+48 others)
2012 X-Ray Free-Electron Lasers: Beam Diagnostics, Beamline Instrumentation, and Applications  
Profiling structured beams produced by X-ray free-electron lasers (FELs) is crucial to both maximizing signal intensity for weakly scattering targets and interpreting their scattering patterns. Earlier ablative imprint studies describe how to infer the X-ray beam profile from the damage that an attenuated beam inflicts on a substrate. However, the beams in-situ profile is not directly accessible with imprint studies because the damage profile could be different from the actual beam profile. On
more » ... he other hand, although a Shack-Hartmann sensor is capable of in-situ profiling, its lenses may be quickly damaged at the intense focus of hard X-ray FEL beams. We describe a new approach that probes the in-situ morphology of the intense FEL focus. By studying the translations in diffraction patterns from an ensemble of randomly injected sub-micron latex spheres, we were able to determine the non-Gaussian nature of the intense FEL beam at the Linac Coherent Light Source (SLAC Downloaded From: http://proceedings.spiedigitallibrary.org/ on 12/05/2016 Terms of Use: http://spiedigitallibrary.org/ss/termsofuse.aspx National Laboratory) near the FEL focus. We discuss an experimental application of such a beam-profiling technique, and the limitations we need to overcome before it can be widely applied. Downloaded From: http://proceedings.spiedigitallibrary.org/ on 12/05/2016 Terms of Use: http://spiedigitallibrary.org/ss/termsofuse.aspx Proc. of SPIE Vol. 8504 850403-4 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 12/05/2016 Terms of Use: http://spiedigitallibrary.org/ss/termsofuse.aspx Proc. of SPIE Vol. 8504 850403-6 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 12/05/2016 Terms of Use: http://spiedigitallibrary.org/ss/termsofuse.aspx
doi:10.1117/12.930075 fatcat:7wfyervn2vh23fhdcwxiihjvni