Particle Background at LEP with Head-On colliding Bunch Trains

The vertical closed orbit bumps around the interaction points in LEP, which are needed to separate counter rotating bunches at their parasitic collision points, generate additional particle backgrounds at the LEP detectors. Monte Carlo simulations of photon and electron backgrounds have been performed and their predictions compared with experimental data. This has led to a good understanding of the bunch train specific background sources and allowed efficient protection measures to be devised.