Summary
Our time-resolved x-ray studies of biomolecules have been pursued on the BioCARS beamline at the Advanced Photon Source (APS), which shut down operations in May 2023 to implement a major upgrade (APS-U) that aims to reduce significantly the horizontal emittance of electrons circulating in the synchrotron. This effort will allow x-rays generated from those electrons to be focused to a smaller spot and will boost the coherence of those focused x-rays. However, the fill patterns required to achieve this goal contain significantly fewer electrons in each bunch. For example, the APS-U will no longe
