Detectors for direct Dark Matter search at KamLAND

Abstract The current status of laboratory for Dark Matter search at the Kamioka mine and specialized facility for production of NaI(Tl) detectors is described. Techniques developed for purification and growth of ultra-low background NaI(Tl) crystals are reported. Achieved activity levels of the 210 Pb, 40 K, 238 U, 232 Th isotopes in the latest NaI(Tl) Dark Matter detector prototypes and the DAMA/LIBRA detectors are compared.