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Figure 2
Triggering scheme of the tape drive and detector synchronization. (a) Because synchrotron X-ray pulses are essentially continuous on the time scale of the droplet motion, a master clock is defined by a signal generator which delivers TTL pulses at the desired frequency (e.g. up to 500 Hz). This master TTL signal triggers the sample droplet ejection by the PEI. The master clock also simultaneously triggers `waveform generator 1' which will produce two TTL signals at the same frequency with delay Δt1 and Δt2, respectively. The first TTL signal triggers the strobed LED attached to the PEI; adjusting Δt1 enables the visualization and calibration of the droplet ejection onto the moving Kapton tape. The second TTL signal triggers both the strobe LED behind the tape that illuminates the X-ray–droplet interaction region and the diffraction detector. By adjusting Δt2, the droplet position on the tape is aligned to the X-ray beam (red arrow), thereby also triggering the detector to acquire diffraction data when droplets overlap the X-ray path. (b) Same as panel (a) except that the master clock runs at 100 Hz, defining the droplet ejection at 100 Hz. Another `waveform generator 2' is placed before the detector generating a 500 Hz signal. This allows ejection of droplets at 100 Hz (black lines) while acquiring images at 500 Hz (red lines).

IUCrJ
Volume 13| Part 5| September 2026|
ISSN: 2052-2525
https://doi.org/10.1107/S2052252526005658