DAPNIA-06-167 |
---|
Design of an interaction region with head-on collisions for the ILC. |
J. Payet, O. Napoly, C. Rippon, D. Uriot , D. Angal-Kalinin, F. Jackson , M .Alabau-Pons, P. Bambade, J. Brossard, O. Dadoun, C. Rimbault , L. Keller, Y. Nosochkov, A. Seryi , R. Appleby |
An interaction region (IR) with head-on collisions is considered as an alternative to the baseline configuration of the International Linear Collider (ILC) which includes two IRs with finite crossing-angles (2 and 20 mrad). Although more challenging for the beam extraction, the head-on scheme is favoured by the experiments because it allows a more convenient detector configuration, particularly in the forward region. The optics of the headon extraction is revisited by separating the e+ and e- beams horizontally, first by electrostatic separators operated at their LEP nominal field and then using a defocusing quadrupole of the final focus beam line. In this way the septum magnet is protected from the beamstrahlung power. Newly optimized final focus and extraction optics are presented, including a first look at post-collision diagnostics. The influence of parasitic collisions is shown to lead to a region of stable collision parameters. Disrupted beam and beamstrahlung photon losses are calculated along the extraction elements. |