Design of Beam and Beamstrahlung Extraction Lines for TESLA

In the TESLA superconducting linear collider project, collisions occur at zero crossing angle. While the outgoing beams are extracted at about 40 m after the interaction point, the beamstrahlung photons travel further upstream along the incoming final focus beam line. Moreover, the option to rapidly dump the spent beams after the collision has been favoured recently to avoid the inconveniencies of large beam losses and beam line activation. For these reasons, the design of the beam and beamstrahlung extraction lines is interplayed with those of the final focus optics and synchrotron radiation masking. We propose a system where the beam extraction is downward and where the beam and beamstrahlung power is dumped at 240 m from the IP. The power deposition along the beam lines and beam transmission to the dump are found to be acceptable