Suppression of pileup events by pulse shape discrimination using the Gatti filter

Abstract

An algorithm is proposed that provides reliable discrimination between neutrons and γ rays in mixed fields and reduces the influence of γ-ray pileups at a slight complication of the hardware and the algorithms. The algorithm uses a stepwise Gatti filter for two detection periods (a short period of several hundreds of nanoseconds and a long period of a few microseconds) for the same event. Using mathematical simulation of 12000 neutron and γ-ray events, it has been demonstrated that at particle energies of ~128 keV in the electron equivalent (ee), the algorithm suppresses γ-ray pileups on a level of 10⁴ with a neutron loss of only approximately 1%. Due to the proposed algorithm, the counting ability is of the order of 10⁵ events/s.