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Design of an interaction region with head-on collisions for the ILC

R. Appleby·D. Angal-Kalinin·F. Jackson·M . Alabau-Pons·P. Bambade·J. Brossard·O. Dadoun·C. Rimbault·L. Keller·Y. Nosochkov·A. Seryi·J. Payet·O. Napoly·C. Rippon·D. Uriot
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Abstract

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 head-on 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.

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R. Appleby, D. Angal-Kalinin, F. Jackson, M . Alabau-Pons, P. Bambade, J. Brossard, O. Dadoun, C. Rimbault, L. Keller, Y. Nosochkov, A. Seryi, J. Payet, O. Napoly, C. Rippon, D. Uriot. 2006-09-28. Design of an interaction region with head-on collisions for the ILC. https://arxiv.org/abs/physics/0609248

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