  (Gd,La)$_2$Si$_2$O$_7$:Ce (La-GPS:Ce) is a new scintillator material with
high light output, high energy resolution, and fast decay time. Moreover, the
scintillator has a good light output even at high temperature (up to
150$^\circ$C) and is non-hygroscopic in nature; thus, it is especially suitable
for underground resource exploration. Particle identification greatly expands
the possible applications of scintillator. For resource exploration, the
particle identification should be completed in a single pulse only. The
pulse-shape discrimination of the scintillator was confirmed. We compared two
methods; a double gate method and a digital filter method. Using digital filter
method (shape indicator), F-measure to evaluate a separation between $\alpha$
and $\gamma$ particles was obtained to be 0.92 at 0.66 MeVee.
