A method is described which permits discrimination between noise pulses and pulses of small light flashes. The arrangement consists of three multipliers facing the three faces of one and the same crystal. One multiplier acts on the ``Y'' axis, another on the X axis and the third one on the Z (intensity) axis of an oscilloscope. Light flashes induce pulses in all multipliers simultaneously, whereas noise‐pulses occur at random and produce triple‐coincidence pulses only very rarely. Triple coincidences are easily recorded with the scope. Pictures are presented illustrating the operation of the arrangement. The original noise being of the order of three thousand per second was dropped to one noise pulse in three seconds.