Abstract
Multiobjective genetic algorithm optimizations of a single-shot ultrafast electron diffraction beam line comprised of a 1.6-cell normal conducting rf (NCRF) gun, as well as a nine-cell bunching cavity placed between two solenoids, have been performed. These include optimization of the normalized transverse emittance as a function of bunch charge, as well as optimization of the transverse coherence length as a function of the rms bunch length of the beam at the sample location for a fixed charge of electrons. Analysis of the resulting solutions is discussed in terms of the relevant scaling laws, and a detailed description of one of the resulting solutions from the coherence length optimizations is given. For a charge of electrons and final beam sizes of and , we found a relative coherence length of using direct optimization of the coherence length. Additionally, based on optimizations of the emittance as a function of final bunch length, we estimate the relative coherence length for bunch lengths of 30 and 100 fs to be roughly 0.1 and , respectively. Finally, using the scaling of the optimal emittance with bunch charge, for a charge of electrons, we estimate relative coherence lengths of 0.3, 0.5, and for final bunch lengths of 5, 30 and 100 fs, respectively.
- Received 14 October 2016
DOI:https://doi.org/10.1103/PhysRevAccelBeams.20.033401
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.
Published by the American Physical Society