FIG. 1.

Relative error in structure factor magnitude measured in Monte-Carlo (MC, middle curve), split-and-delay or two-color (SD, 2C, lower curve), and non-destructive mode of goniometer-based fixed sample (FS, upper curve) approaches for TR-SFX. To identify 1% change in structure factor in pump-probe experiments, less than 100 pairs of patterns are needed in two-color or split-and-delay mode, compared to approximately 80 000 patterns required in the Monte-Carlo approach. The non-destructive mode of goniometer-based fixed sample approach gives an error limited by the X-ray dose, but independent of sampling. The diffract-and-destroy mode, using fixed samples, yields an error with a prefactor of 0.57%, but the number of patterns collected from one single crystal is limited by the crystal size and the distance between consecutive shots in order to avoid radiation damage. Diffraction from micro-crystals trapped on a calibrated lattice follows essentially the same error reduction behavior as the Monte-Carlo approach using the liquid jet delivery system.