Ground Vibration and Coherence Length Measurements for the CLIC Nano-Stabilization Studies

The demanding nanometre transverse beam sizes and emittances in future linear accelerators result in stringent alignment and nanometre vibration stability requirements. For more than two decades, ground vibration measurements were made by different teams for feasibility studies of linear accelerators. Recent measurements were performed in the LHC tunnel and at different CERN sites on the surface. The devices to measure nanometre sized vibrations, the analysis techniques and the results are critically discussed and compared with former measurement campaigns. The implication of the measured integrated R.M.S. displacements and coherence length for the CLIC stabilization system are mentioned.