There is considerable experimental effort dedicated to the directional detection of particle dark matter. Gaseous mu-TPC detectors present the privileged features of being able to reconstruct the track and the energy of the recoil nucleus following t
he interaction. A precise measurement of the recoil energy is a key point for the directional search strategy. Quenching has to be taken into account, i.e. only a certain fraction of the recoil energy is deposited in the ionization channel. Measurements of the ionization quenching factor for different gas mixture at room temperature have been made with a dedicated ion beam facility at the LPSC of Grenoble.
