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- K. Schindl, A. Beuret, A. Blas, J. Borburgh, H. Burkhardt, C. Carli, M. Chanel, T. Fowler, M. Gourber-Pace, S. Hancock, C.E. Hill, M. Hourican, J.M. Jowett, K. Kahle, D. Kuchler, A.M. Lombardi, E. Mahner, D. Manglunki, M. Martini, S. Maury, F. Pedersen, U. Raich, C. Rossi, J.-P. Royer, R. Scrivens, L. Sermeus, E.N. Shaposhnikova, G. Tranquille, M. Vretenar, T. Zickler
CERN, Geneva
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A sizeable part of the LHC physics programme foresees heavy ion (lead-lead) collisions with a design luminosity of 1027 cm-2 s-1. This will be achieved after an upgrade of the ion injector chain comprising Linac3, LEIR, PS and SPS machines. Each LHC ring will be filled in ~10 minutes with ~600 bunches, each of 7 107 Pb ions. Central to the scheme is the Low Energy Ion Ring (LEIR), which transforms long pulses from Linac3 to high-brilliance bunches by means of 6D multi-turn injection and accumulation via electron cooling. Major limitations along the chain, including space charge, intra-beam scattering, vacuum issues, and emittance preservation are highlighted. The conversion from LEAR (Low Energy Antiproton Ring) to LEIR includes new magnets and power converters, high-current electron cooling, broad-band RF cavities, upgraded beam diagnostics, and UHV vacuum equipment relying on beam scrubbing to achieve a few 10-12 mbar. Major hardware changes in Linac3 (Electron Cyclotron Resonance source, repetition rate, energy ramping cavity), PS (new injection hardware, elaborate RF gymnastics, stripping insertion), and SPS (100 MHz system) are described. An early beam scenario, using fewer bunches but the same bunch intensity to deliver a lower luminosity, reduces the work required for LHC ion operation in spring 2008.
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