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Figure 3
(a) Correlations obtained after 4.4 µs (circles), 13.3 µs (diamonds) and 62.0 µs (squares) hitting the sample with a fluence of 3.9 mJ mm−2 (blue symbols) and 10.5 mJ mm−2 (red symbols). The black lines are exponential fits to the data. Within the sensitivity given by the XFEL intensity fluctuations, the dynamics within a train of pulses remain stationary for the lower fluence, whereas in the higher fluence the relaxations are faster for larger t1. For clarity only the correlations from one q of sample B are reported, but other qs in other samples provide the same qualitative information. The error bars on the data points are obtained from the variance of the two-time correlation matrix. (b) [-\ln{|f_{q}(t)|}] for sample B. All the ISFs are completely decorrelated (i.e. the measurement noise overcomes the dynamic signal) after reaching the interaction time τI, here highlighted by the black dashed line. It is evident that, for higher q, the useful portion of the ISF is rather limited. The dotted lines are the fits to Equation (9)[link] over the appropriate time regime.

Volume 8| Part 5| September 2021| Pages 775-783
ISSN: 2052-2525