European Laboratory for Particle Physics CERN  SL DIVISION Geneva, Switzerland 10 October, 1999 CERN-SL-98-058 (EA) Synchrotron Radiation Power from Insertion Quadrupoles onto LEP Equipment A. Butterworth, G. Cavallari, M. Jimenez, G. von Holtey Abstract Hot spots and leaks at vacuum transition pieces in the experimental straight sections at high beam energy have been shown experimentally as well as by simulation to be due to synchrotron radiation from the low-beta quadrupoles. The transition pieces can be effectively protected by collimators. However, when closed, the collimators themselves are hit by a very high flux of synchrotron radiation photons, amounting to several hundreds of Watts per mA of beam current. The power seen by the collimator jaw surface is strongly dependent on the horizontal closed orbit amplitude through the quadrupoles. Upper limits for asymmetric horizontal orbits in the even IP’s are given in order to keep the incident power onto collimators below design values.