Results with the 101/45 degree optics

A new optics with a phase advance of 101/45 degrees has been commissioned in LEP and used for polarization, spectrometer and energy calibration studies in 1999. Sufficient polarization for energy calibration (by resonant depolarization) was established from 41 GeV to 60 GeV. In agreement with expectations the level of polarization was similaror somewhat higher than with the 60/60 optics. In particular the newoptics allowed establishing polarization at 60.6 GeV, which had failed in several attempts for the 60/60 optics in 1999.With the 101/45 optics transverse spin polarization was measured for the first time in the regime of very strong synchrotron radiation. A level below 1% was measured at 70 GeV, 92 GeV and 98.5 GeV inagreement with theoretical predictions (compatible with zero polarization).A hypothetical increase of polarization at high energy was not observed. Beam energy measurements with the spectrometer were performed in parallelto polarization studies, spanning the range from 41 GeV to almost 100 GeV.The new optics exhibited good operational stability. The longest fill lasted 34 hours with five different beam energies ranging from 41 GeV to 98.5 GeV. The high horizontal phase advance avoids problems with RF stability as for the 60/60 optics. The vertical RMS dispersion was reduced to below 1 cm with a minimum value of 0.8 cm.