Caption: Time distribution within the beam trigger window of all subevents. The beam spill occurs between ~4500ns and ~6500ns. The increase in subevent rates during the beam spill and the exponential decay in the rate after the beam spill is due to "Michel" electrons from the decay of stopping muons produced by charged current neutrino interactions. The pile-up at the beginning of the window is due to background events that occurred just before the trigger window but still produced PMT hits within the trigger window.