Determination of time over threshold for two hits in the same fiber and fiber efficiency

The first project is to study studying the time over threshold (ToT) distribution which shown two peaks distribution and understand FACT digital response. All data in form of root file are vector contained of these hits which sorted by starting times (Clock). In the FACT detector, there are many events of antiproton annihilation which produced pions that passed through the fibers. However, there are some two pions hit the same fiber which gives the time differences between two hits in the same fiber. The implementation of functions provided in the gAn to plot the ToT distribution between two hits in the same fiber. Next, the determination of fiber efficiency by using mathematically approach without considering studied fiber to get every efficiency of fiber for each layer. The idea is let try to consider that there are two cases, a) possible hits can formed track (4,3 and 2 fibers are fired) and b) impossible hit/hits which impossible to form track (1 and 2 are fired). The is to match the combinations of 4 and 3 layers track, 3 and 2 layer tracks, and 2 and 1 layer tracks in order to get efficiency of each fiber layer. Overall, what I realized is I repeating the same combinations to get every efficiency fiber and tried to figure out the more combinations too. Unfortunately, the estimator of fiber efficiency either biased or non-biased could not get.