The EDELWEISS-III Project and the Rejection Performance of Its Cryogenic Germanium Detectors

The EDELWEISS-III experiment searches for Dark matter using cryogenic germanium detectors in the low radioactivity environment of the Laboratoire Souterrain de Modane. The experiment and the FID detector design, whereby all surfaces are covered with interleaved electrodes, are described. The performance for gamma-ray and surface event rejection of these detectors is discussed. In particular, recent calibrations with a Pb source reveals that the excellent surface event rejection already demonstrated with planar interleaved electrodes also extends to the entire surface of the large FID detectors, even on their cylindrical outer surfaces, where the electric field has a more complicated geometry. Expected results with the full exposure of the EDELWEISS-III experiment are discussed.