A NOVEL COINCIDENCE METHOD - SIMULTANEOUS RECORDING OF TRUE AND RANDOM COINCIDENCES BY DOUBLE PULSES

A description is given of a fast coincidence method capable of detecting and subtracting the random coincidences from the total number of coincidences recorded during course of the experiment. Double pulses are formed in each channel. Their coincidences are used to determine whether the event is true or random. From the number of prompt coincidences (true plus random) the number of delayed (random) coincidences is subtracted. The method is quite unambiguous and very simple. Several advantages are seen in comparison with conventional methods. The principle suggested here has a unique resolving time, the same for true and random coincidences. The method is particularly useful in experiments where the half life of the source is short or when the source is subjected to large intensity fluctuations. The overall system and a brief circuit description are presented together with some experimental results, obtained from coincidence measurement, subnanosecond time resolution curves and angular correlations. The capability and limitations of the method are discussed. © 1969.