Micrometric Propagation of Error Using Overlapping Streched Wires for the CLIC Pre-Alignment

The geodetic network for the Compact LInear collider (CLIC) will consist of a combination of overlapping wires stretched in parallel and Wire Positioning Sensors (WPS). Such a configuration will limit the propagation of errors (maximum deviation w.r.t. a fit line) below 10 micrometres over 200 metres. These first results were obtained through simulations in 2009, with hypotheses remaining to be validated. New experimental results have been obtained allowing to reconsider the precision and accuracy of WPS sensors and the knowledge of stretched wires. This paper presents the experimental results obtained on dedicated calibration benches and on a facility made of three overlapping stretched wires over a length of 140 metres including WPS sensors measurements. It confirms the possibility to have a propagation of error below 10 micrometres using overlapping stretched wires combined with WPS sensors.