Supplementary Figure 1: Photograph of the DOT system and details of the optical pump setup.
From: Drop-on-demand sample delivery for studying biocatalysts in action at X-ray free-electron lasers
a. A photograph of the drop-on-tape (DOT) device mounted at the X-ray Pump Probe (XPP) endstation of the Linac Coherent Light Source (LCLS) with various important components labeled. b. Schematic of the fiber optics setup for sample illumination. c. Example output of the feedback system to ensure that drop deposition is in phase with laser pump pulses. The arrival time of each drop over one of the IR “gates” is detected by changes in the IR transmission (yellow and pink traces). In addition, the laser transmission of the sample at each of the three illumination points on the tape for each individual drop is measured (blue and green traces shown here are for the pump #2 and #3) and delays are tuned to bring the IR and pump signals in phase. This information can also be used after the experiment to reject signal from drops that did not receive the correct illumination.
