Low temperature mechanical dissipation measurements of silicon and silicon carbide as candidate material for DUAL detector

We present the results of measurements of mechanical dissipation in silicon and silicon carbide samples within 2-300 K range of temperature. These materials are possible candidates for the sensitive mass of DUAL detector. We have investigated sintered and infiltrated Silicon-Carbide (SiC) and P-doped Silicon (Si)in flat plates and cantilevers. Moreover the dissipation of bonded P-doped silicon wafers is scheduled for measurement in the 2-300 K range for the next cryogenic run. We tested a nodal suspension with sapphire and inox steel spheres for flat plates within the same temperature range. We develop two different kinds of capacitive readout: electrostatic comb one for semiconductor silicon and plane capacitor-like for conductor silicon carbide. Moreover an optical lever readout was employed to measure loss angle on SiC cantilevers and silicon disks.