  KIMS-NaI is a direct detection experiment searching for Weakly Interacting
Massive Particles (WIMP) via their scattering off of nuclei in a NaI(Tl)
crystal. The KIMS-NaI collaboration has carried out tests of six crystals in
the Yangyang underground laboratory in order to develope low-background NaI(Tl)
crystals. Studies of internal backgrounds crystals have been performed with the
goal of reducing backgrounds levels to 1 dru at 2 keV. Pulse shape
discrimination (PSD) capabilities were also investigated for distinguishing
between WIMP nuclear recoil signals and electron recoil backgrounds. The PSD
analysis was applied to underground data with one low background NaI(Tl)
detector and the evaluation of WIMP mass limit is ongoing.
