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Collimation MDs. Daniel Wollmann for the Collimation-Team, BLM-Team, Impedance-Team, … LHC Study Working Group, 19.04.2011. Outline. Nominal Collimation settings with parallel impedance measurement Quench test in the DS of IR7.
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Collimation MDs Daniel Wollmann for the Collimation-Team, BLM-Team, Impedance-Team, … LHC Study Working Group, 19.04.2011
Outline • Nominal Collimation settings with parallel impedance measurement • Quench test in the DS of IR7
Collimator Settings – Intermediateas currently in the machine • Intermediate: keep distance to primary collimators constant in millimeters during the ramp • Nominal: keep distance to primary collimator constant in beam sigma during the ramp
Better cleaning with nominal collimation settings worse Factor >2 better cleaning at 3.5TeV predicted R.W. Assmann, 2009 better Tight: Best performance but increasingly tight tolerances.
Nominal Collimator settings • 3.5 TeV • Max Intensity: 3e11p • Close gaps of collimators in steps from operational, intermediate settings tonominal settings • Tune shift observations during step wise movement of collimator families • Qualification with loss maps (B1/B2 h/v, one off-momentum) • If time: test 7TeV (factor 1.4 smaller) settings with low emittance LHC beam
Quench test in the DS of IR7 • Losses into DS of IR7 are predicted to define the collimation dependent intensity limit • Measured as predicted: Losses of single diffractive protons in DS (off-momentum particles, loss positions independent of plane of losses) • Quench test will allow to better specify the collimation dependent intensity limit. • Optimization of BLM threshold in the DS • Results will possibly impact the collimation upgrade scenarios
Single Diffractive Protons lost in DSZoom IR7-IR8 Losses of single diffractive protons after interaction with primary collimator (off-momentum protons)
Losses during stable beams (336b) - Today IR7 Luminosity dependent losses in the DSs of the experimental IRs (off-momentum particles) IR3 IR6
Quench test in the DS of IR7 • 3.5 TeV (450GeV not sufficient, need single diffractive losses) • Max Intensity: 1e13p • Create high losses at primary collimators in IR7 • Maximum losses in cold aperture expected to appear in DS • Produce realistically distributed losses in DS (dilution, loss spots, … ); not possible with bump