The New Layout of the LHC Cleaning Insertions

The improved LHC collimation system required significant changes in the layout and design of the warm insertions. Requirements for collimation, optics, impedance, vacuum, and additional infrastructure are described and the adopted layout is presented. Various design principles have been explored during the re-design. Magnet positions and collimators were moved significantly, such that a good cleaning efficiency was maintained while impedance was reduced by almost a factor of two. Space for upgrades of the collimation system was reserved (metallic phase 2 collimators would allow for a better efficiency than originally achievable). Scrapers were allocated for beam shaping and diagnostics. The required infrastructure was specified, including a powerful cooling system for the collimators.