[en] A method is proposed for measuring the mean time of a Q-th electron's emergence from the photocathode of a photoelectric multiplier by recording the photones with a scintillation detector. A peculiarity of this method is that it integrates two consecutive pulses from the photoelectric multiplier and measures the decrease in the amplitude of voltage pulses. The method can be used to control the quality of the photocathode of an electric multiplier