On the physical origin of tails in the time response of spark counters

The time response function of a spark counter is calculated considering that the time delay and its fluctuations originate from the avalanche growth, under space charge effects. The deduced asymmetric time response probability density displays a peak and a tail which both correlate with an increase of the overall time delay. From a comparison to experiment, it is shown that the calculations can reproduce the general trends of the measurements.