  In recent decades, inorganic crystals have been widely used in dark matter
direct search experiments. To contribute to the understanding of the
capabilities of $CsI(Na)$ and $CaF_{2}(Eu)$ crystals, a mono-energetic neutron
beam is utilized to study the properties of nuclear recoils, which are expected
to be similar to signals of dark matter direct detection. The quenching factor
of nuclear recoils in $CsI(Na)$ and $CaF_{2}(Eu)$, as well as an improved
discrimination factor between nuclear recoils and ${\gamma}$ backgrounds in
$CsI(Na)$, are reported.
