Tune scans in LEP

Luminosity optimization in LEP required systematic studies of the dependence of some beam parameters on the values of the betatron tunes. For this purpose a measurement sequencer was conceived in the environment of the LEP control system which : a) changed the betatron tunes at a speed of about 0.5 Hz and b) acquired data from various beam instruments, such as transverse emittances, beam lifetimes and tunes, at a rate of about 2 Hz. This paper summarizes the experimental procedure and the subsequent data treatment. Results on the beam sizes as a function of the betatron tunes are shown.