Pulse Shape Discrimination Algorithms

Algorithms from Digital approaches to field neutron spectrometry

Charge Comparison Algorithm

To find the discrimination parameter, integrate over the long interval, which spans the sum of all the samples, and integrate over the short interval, which is the tail of the pulse. (Note: The long integral is proportional to the total light output.)

The advantage of this algorithm is that it is said to be the simplest of the three and “it would be desirable to implement the Charge Comparison algorithm as embedded code in the FPGA…”

 

Pulse Gradient Analysis (PGA) Algorithm

To find the discrimination parameter, take a sampling pulse voltage at a specific time after the peak and then find the ratio of that sampling point to the peak amplitude. (Note: The ratio is larger for neutron event than a gamma event.)

Model Pulse Algorithm

First, gamma and neutron pulses are created. Then the unknown pulses are then characterized by the pulse that is most similar by using chi-squared. The discrimination parameter is the difference between chi-squared for the gamma model and chi-squared for the neutron model.