Evaluation of Frequency Scanning Interferometer Performances for Surveying, Alignment and Monitoring of Physics Instrumentation

During the last three years, the performance of Frequency Scanning Interferometry, accurate to a few micrometres, has been evaluated at CERN in the frame of the PACMAN project. Improvements have been studied and tested to make it better suited for typical alignment and survey conditions in accelerators and experiments. The results of these developments and tests, coupled with the multi-channel capability of the system, and its compactness which eases its integration in the area to be surveyed, offer a wide scope of possible applications for in-situ large scale metrology for physics equipment and facility elements. Furthermore, the fact that the system electronics can be placed far away from the position to be measured, allows the system to be used in confined and hazardous spaces. This paper briefly describes the system and its improvements. It gives the precision obtained for distance measurements and for the 3D point reconstruction based on FSI observations in the case of CLIC component fiducialisation.