Energy Calibration with Resonant Depolarization at LEP in 1993

An important goal for the 1993 LEP running was the improved measurement of the mass and the resonance width of the Z boson. Regular and accurate calibration of the LEP beam energy by resonant depolarization was essentially needed to reach the required precision. We show how energy calibration was achieved on a regular basis and for all three operational LEP beam energies in 1993. The results taken over the year are presented. Possible systematic errors on energy calibration are very important and were studied in detail. As an interesting side effect measurements of tidal changes of the beam energy are shown.