The enzyme crystals are ejected by an acoustic droplet ejector (ADE) and synchronized to the XFEL master clock. The burst of substrate drops is ejected by a piezoelectric injector (PEI) that can accommodate cartridges with openings of various sizes that dictate the volume of the droplets. Reaction time is varied by the speed of the tape drive (10–600 mm/sec) and depends upon the location of the PEI with respect to the ADE droplet intersection and the X-ray interaction points.
