Analysis on Fast Neutron Pulses Generated by a Deuterated Organic Scintillator (EJ-315)

This paper starts with an experimental setup for fast neutron detection with a time-of-flight path of 10-m-long, and then describes a mechanism used to interpret an errors regarding on event identification of a widely used charge- integration pulse shape discrimination algorithm. Pulses of regular neutrons, misjudged neutrons, and gamma rays are compared in order to investigate the reason why a fraction of gamma-ray pulses are misinterpreted as neutron pulses in event identification. To quantitatively investigate the scintillation proprieties of a deuterated scintillation detector, EJ-315, average pulses of several groups of neutrons with different energy are analyzed. A mathematical model convoluting an exponentially modified Gaussian distribution has been applied to fit scintillation pulses. Reasonable fittings with convergence during optimal parameter searching were achieved by a simplex algorithm method. The short and the long decay time constant values were measured as 7.75 ns and 63.25 ns, respectively. Reasons for measurement discrepancies with declared values are discussed in the context of measurement setup.