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The ATS MDs (Achromatic Telescopic Squeezing scheme).
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The ATS MDs(Achromatic Telescopic Squeezing scheme) Participants: C. Alabau, R. Assmann, R. Calaga, R. De Maria, S. Fartoukh, M. Giovannozzi, B. Goddard, W. Hofle, R. Miyamoto, G. Muller, S. Redaelli, M. Strzelczyk, R. Steinhagen, E. Todesco, R. Tomas, G. Vanbavinckhove, Jorg Wenninger, F. Zimmerman. Theme: LHC Nominal (b* 30 cm if permitted by emittance and IT aperture) + HL-LHC(b* 15 cm or 30/7.5 cm: “round” or “flat optics”) Number of MDs requested: 5+1 (in 2011/2012) Type of beams: 1E10 (1 bunch/beam), ge<1.5 mm safe beam First MD block: - Wed 12:00/16:00 HWC of injection + ramp w/o beam - Sat 12:00/20:00 Beam commissioning of the new inj. optics (+ramp) S. Fartoukh, LSWG 19/04/2011
Overall Plan 3 different phases • Phase A: new injection optics + ramp In particular new tunes Qx/y=62.28/60.31 (see MD proposal and slide 4 for other details) • Phase B: “Standard”pre-squeeze @ 3.5 TeV to b*=1.2 m in IR1/5, • other choice possible in between 40 cm (limited by MS strength at 7 TeV) and 2 m (limited by IR1/5 quad strength at 7 TeV with specific Left/Right phase advances) • Phase C: Continuation of the squeeze down to b*=30 cm in IR1, • At constant settings in IR1, but using IR8 and IR2 and increasing the peak b-functions by a factor of 4 in s81 and s12. • Status of preparation: • Optics repository near to completion (SF):afs/cern.ch/eng/lhc/optics/ATS_V6.503 • Setting generation: on-going (SR, GM et al.) • a2 global knob and b2 pre-settings in preparation (CA, MS) • b-beating team ready soon (RT et al.) S. Fartoukh, LSWG 19/04/2011
Illustration for IR1 applying the ATS scheme to reach b*= 10 cm (pre-squeeze to 40 cm and further squeeze by a factor of 4 using IR8 and IR2) Beam sizes [mm] at 3.5 TeV (ge=1.5mm) and dispersion [m] for Beam1 from Q13.L8 to Q13.R2 S. Fartoukh, LSWG 19/04/2011