Influence of mechanical vibrations on the field quality measurements of LHC interaction region quadrupole magnets

The high gradient quadrupole magnets being developed by the US-LHC Accelera tor Project for the LHC Interaction Regions have stringent field quality re quirements. The field quality of these magnets will be measured using a rot ating coil system presently under development. Mechanical vibrations of the coil during field quality measurements are of concern because such vibrati ons can introduce systematic errors in measurement results. This paper pres ents calculations of the expected influence of vibrations on field quality measurements and a technique to measure vibrations present in data acquired with standard "tangential-style" probes. Measured vibrations are reported and compared to simulations. Limits on systematic errors in multipole measu rements are discussed along with implications for probe and measurement sys tem design.