  The R&D project COSINUS (Cryogenic Observatory for SIgnatures seen in
Next-generation Underground Searches) aims to develop a cryogenic scintillating
calorimeter using NaI as target crystal for direct darkmatter search. Dark
matter particles interacting with the detector material generate both a phonon
signal and scintillation light. While the phonon signal provides a precise
determination of the deposited energy, the simultaneously measured
scintillation light allows for a particle identification on an event-by-event
basis, a powerful tool to study material-dependent interactions, and to
suppress backgrounds. Using the same target material as the DAMA/LIBRA
collaboration, the COSINUS technique may offer a unique possibility to
investigate and contribute information to the presently controversial situation
in the dark matter sector. We report on the dedicated design planned for the
NaI proof-of-principle detector and the objectives of using this detection
technique in the light of direct dark matter detection.
