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. Author manuscript; available in PMC: 2022 May 17.
Published in final edited form as: Nat Methods. 2019 Nov 18;17(1):73–78. doi: 10.1038/s41592-019-0628-z

Fig. 2|. Pulse train structure and laser excitation.

Fig. 2|

a, X-ray pulse trains (black vertical lines) at EuXFEL with 1.13 MHz pulse repetition rate. A pulse train is 156 μs long, contains 176 X-ray pulses and repeats 10 times per second. There are 99.84 ms gaps between the pulse trains. Blue: laser pulses for a pump-probe dark TR-SFX data collection scheme. Note: when EuXFEL design specifications are reached, 2700 pulses with up to 4.5 MHz pulse repetition rate are in a train. At 4.5 MHz, each pulse train is 600 μs long with 99.4 ms gaps between the trains. In total there are 27,000 pulses/s, a subset of which (about 3520/s) can be stored in, and read out, by in the AGIPD detector. b, 1.13 MHz control experiment with 376 kHz laser excitation. After the laser pulse, subsequent X-ray pulses arrive at 887 ns, at 1.78 μs and at 2.67 μs. The sequence repeats until the end of the pulse train. c, 564 kHz data collection with three interleaved X-ray pulses. 88 pulses are in the train, only. The laser pulses are separated by 7.1 μs (141 kHz) to provide enough time for the laser excited volume (red) to move out of the X-ray interaction region. 519,336 diffraction patterns were averaged to determine the scheme.