Speaker
Description
We introduce the SLS-Id instrument (Straylight Sources Identifier), designed to measure the amount of light backscattered by any optical components within an integrated optical system. Its application for the Virgo optical benches allows to identify any pathological components, from the straylight perspective, through a system-level measurement. This means that a single measurement will provide the backscattered light contribution for each individual component without the need for its disassembly for further characterization. The SLS_Id provides also the position of each contributor. While the SLS_Id makes in-situ measurements possible it can be used during the assembly phases of the benches and for long-term monitoring to detect possible ageing of components, accidental particle contamination during maintenance phase, consequence of systems alignment drifts which make the beams wander towards scratchy areas of components surface. We present the instrument's design concept and its performances. Currently the SLS_Id detects backscattered light contributions from high quality optics featuring a few ppm of total integrated scattering with a signal-to-noise ratio up to ten. It provides the position of each contributor with a precision of less of a millimeter (we target ¼ mm in the next future). This feature could be used to assess the distance between components.