In order to make a seismic survey of the tunnel North for the future installation of the FDS filter cavity, today we placed a Trilium seismometer around 50 m far from the BS tower. In particular, we placed it on the floor in correspondence of a pillar. A portable data aquisition system is used to acquire and store data. A GPS antenna is connected to the same system and carried out of the tunnel to synchronized data. Data acquisition started at 17:30 LC. Tomorrow we will install a second Trillium seismometer in a different position along the tunnel beam.
Few pictures in the attachments.