a process for identifying and rejecting pile - up pulses in a system is provided . preferably , the process is applied to mine detection where time is at a premium . a thermal neutron activator sensor trails a mine - detecting vehicle and is dwells over the coordinates of a target of interest for a short a time as possible . the tna interrogates the object with slow neutrons , the required time being brief due to the use of a strong source coupled with a the process for analyzing the resultant high number and rate of pulses and rejecting piled - up pulses . specifically , low energy pulses are removed and the remaining pulse is analyzed for its shape in comparison to the known shape of a non - piled - up pulse . the pulse is integrated using a gated integrator between a designated portion the pulse and for the whole pulse . for a normal pulse , the difference between the two integrations produces a repeatable baseline which is zeroed out to a null difference . thus any non - zero difference is illustrative of a piled - up pulse which can be rejected , thereby maintaining high count rates while continuing to distinguish and count nitrogen - related events indicative of explosives .