Author: F. Tecker
Co-Author: W. Coosemans, A. Marin, K. Rybaltchenko, J. Wenninger
HLS-based Closed Orbit Feed-back at LEP
Hydrostatic Leveling Systems (HLS) measure the vertical positions at different locations around the experimental interaction point of LEP. In particular, the positions of the strong low-beta insertion quadrupoles are of special importance. These magnets are the major source of vertical orbit drifts due to their strength, the large vertical beta function and their support. This presentation will cover the experience with the HLS and the applications of the measurements. A feed-back system uses the measured positions to calculate an orbit correction and prevents large orbit variations.