UNIV ROMA TOR VERGATA,DIPARTIMENTO FIS,I-00173 ROME,ITALY
; ACAD SINICA,IHEP,BEIJING 100039,PEOPLES R CHINA
; CENS,DSM,DAPNIA,SPP,F-91191 GIF SUR YVETTE,FRANCE
; IST NAZL FIS NUCL,SEZ ROMA,I-00185 ROME,ITALY
; IST NAZL FIS NUCL,SEZ ROMA 2,I-00173 ROME,ITALY
A development is in progress in order to detect dark matter particles with NaI crystals. This study is performed in parallel in three underground laboratories (Gran Sasso, Frejus and Mentogou) where the experimental set-ups are efficiently protected from cosmic radiation. Some data are presented on measurements of radioactive contaminants as well as preliminary results from the analysis of low energy event rates. The presently achieved sensitivity to axial coupling WIMPs is comparable to that obtained by germanium experiments. Systematic investigations are under way to further decrease the radioactive background in all elements of the installation.