Influence of pileup rejection on nuclear counting, viewed from the timedomain perspective
Abstract
Timeinterval density distributions of accepted events in a HPGe γray detection setup are measured with a timeinterval digitiser. In particular, the effect of pulsepileup rejection is investigated. Experimental data are obtained with two types of shaping amplifiers: a classical amplifier with semiGaussian pulse shaping and a gatedintegrator amplifier. A theoretical model is developed to predict typical timeinterval density distributions for stationary Poisson processes passing through a detector with count loss by pulsepileup rejection. Good agreement is obtained between theoretical, measured and simulated timeinterval spectra. It is found that, when counting is affected by pileup rejection, the true incoming count rate cannot simply be determined by fitting an exponential to the timeinterval distributions. From the Laplace transform of the intervaldensity distribution, expressions are derived for the expectation value and the variance of the counts. Good agreement is found with experimental counting statistics for different system configurations, as well as with data from computer simulations.
 Publication:

Nuclear Instruments and Methods in Physics Research A
 Pub Date:
 May 1999
 DOI:
 10.1016/S01689002(99)000169
 Bibcode:
 1999NIMPA.426..564P