  Digital pulse shape discrimination has become readily available to
distinguish nuclear recoil and electronic recoil events in scintillation
detectors. We evaluate digital implementations of pulse shape discrimination
algorithms discussed in the literature, namely the Charge Comparison Method,
Pulse-Gradient Analysis, Fourier Series and Standard Event fitting. In
addition, we present a novel algorithm based on a Laplace Transform. Instead of
reducing the performance of these algorithms to a single Figure of Merit, we
evaluate them as function of recoil energy. Specifically, using commercial
EJ-301 liquid sctintillators, we examine both the resulting acceptance of
nuclear recoils at a given rejection level of electronic recoils, as well as
the purity of the selected nuclear recoil event samples. We find that both a
Standard Event fit and a Laplace Transform can be used to significantly improve
the discrimination capabilities over the whole energy range. Furthermore, we
show that the Charge Comparison Method performs poorly in accurately
identifying nuclear recoils.
