Estimating signal and noise of time-resolved X-ray solution scattering data at synchrotrons and XFELs

Kim, J.; Kim, J.G.; Ki, H.; Ahn, C.W.; Ihee, H.

doi:10.1107/S1600577520002738

Figure 7
Comparison of S-cube simulation of photoisomerization of azobenzene (AB) at PAL-XFEL and LCLS-II HE and 4,4′-dibromo azobenzene (Br₂AB) at PAL-XFEL. The black, red and blue curves are simulation results with noise, simulation results without noise, and the residuals between simulation results with and without noise, respectively, and the magenta lines are solute-only signals. (a) S-cube simulation of photoisomerization of AB in cyclohexane at PAL-XFEL with accumulation time of 60 s and repetition rate (f) of 30 Hz, which corresponds to 540 difference scattering curves. (b) S-cube simulation of photoisomerization of Br₂AB in cyclohexane at PAL-XFEL with accumulation time of 60 s and f of 30 Hz, which corresponds to 540 difference scattering curves. (c) S-cube simulation of photoisomerization of AB in cyclohexane at LCLS-II HE with accumulation time of 60 s, f of 1 MHz, which corresponds to 18000000 difference scattering curves. σ_solvent(q) at LCLS-II HE is scaled from σ_solvent(q) at PAL-XFEL with each value of photons per curve which are 3 × 10¹⁰ for LCLS-II HE and 1 × 10¹² for PAL-XFEL. The y-axis indicates qΔS(q), the difference scattering intensity multiplied by q. The difference scattering intensity, ΔS(q), is scaled by the number of solvent molecules and has the unit of electron units (e.u.).

JOURNAL OF
SYNCHROTRON
RADIATION

ISSN: 1600-5775

Volume 27| Part 3| May 2020| Pages 633-645

https://doi.org/10.1107/S1600577520002738

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