\label{fig:altern_hist_double}Alternation histograms for μs-ALEX and ns-ALEX measurements. Histograms used for the selection/determination of the alternation periods for two typical smFRET-ALEX experiments. Distributions of photons detected by donor channel are in green, and by acceptor channel in red. The light green and red shaded areas indicate the donor and acceptor period definitions. (a) μs-ALEX alternation histogram, i.e. histogram of timestamps modulo the alternation period for a smFRET measurement (in timestamp clock unit). (b) ns-ALEX TCSPC nanotime histogram for a smFRET measurement (in TDC or TAC bin unit). Both plots have been generated by the same plot function (plot_alternation_hist()). Additional information on these specific measurements can be found in the attached notebook (link).