Visit to CERCA

Elena Quaranta

on behalf of the collimation teamCWG Collimation Working Group May 2013Cleaning performance of LHC collimation system during the energy ramp 1OutlineElena Quaranta2Motivation of the studySixTrack simulation during the rampGeneral simulation setupEnergy and collimator setting changingCollimator positions changing onlyEnergy changing onlyComparison of simulated casesMeasurement in the LHC (Nov. 2012)Betatron loss maps during the rampSixTrack vs LHC measurementsSummaryElena Quaranta3Motivation of the studySixTrack Simulation during the rampElena Quaranta44Elena Quaranta5General simulation setupElena Quaranta6Energy and Collimator Setting changingLocationCollimatorHalf gap []450 GeV1 TeV1.5 TeV2 TeV2.5 TeV3 TeV3.5 TeV4 TeVIR3TCP88.629.189.7510.310.911.412TCSG9.310.311.212.112.913.814.715.6TCLA1011.212.213.314.415.516.517.6IR7TCP5.75.485.295.094.894.694.54.3TCSG6.76.646.586.536.476.416.366.3TCLA109.749.59.269.028.788.548.3IR6TCSG77.027.037.047.067.077.097.1all IRsTCT131516.818.720.522.324.326Elena Quaranta7Energy and Collimator Setting changing

450 GeV2 TeV4 TeV1 TeV

Elena Quaranta8Energy and Collimator Setting changing

Elena Quaranta9Energy and Collimator Setting changing- Impact parameter modified -Impact parameter changingNo significant modifications!Separate simulations performed by varying only the energy or the position of the jaws to isolate the effects of the energy dependence of the scattering and the collimator movements with respect to the apertureElena Quaranta10Collimator positions changing only

Energy constantCoulomb scattering physics unchangedCollimators moving closer to beam centerScattering angles not enough to make particle reach the aperturebutsoElena Quaranta11Energy changing only

Probability to hit TCSsMultiple Coulomb scattering angle Change in particle-matter interaction inside jaw when energy increasessoProtons absorbed in collimation systemElena Quaranta12Comparison of simulated cases

Statistical errorGood superposition of the two effectsMeasurements in the LHC (Nov. 2012)Elena Quaranta1313Elena Quaranta14Betatron loss maps during the ramp

2 TeV - simulated

Higher leakage in IR6 (cfr: IPAC13 R. Bruce)2 TeV - measuredElena Quaranta15SixTrack vs LHC measurement

TCP.C6L7.B1TCTH.4L8.B1MQ in Q8TCSG.4R6.B1MeasurementSimulationElena Quaranta16SixTrack vs LHC measurement- Main issues -Elena Quaranta17SummaryLHC energy ramp simulated by SixTrack, tracking particles at intermediate energies, from injection to flat topDifferent cases analyzed to better understand the aspects that mainly affect the collimator performanceEnergy and collimator opening counter-acting each other in the determination of the cleaning inefficiencyNov. 2012 (MD#4): data taken from BLMs signal, after ADT excitation of B1 and B2 in H planeVery good agreement between simulation results and measurements, within uncertainty from BLMs vs losses of beam protonsIncreased confidence in SixTrack ability to reproduce the energy dependence of collimator inefficiencySixTrack well benchmarked to simulate future LHC scenarios at higher energiesQuestions? Comments?Remarks?Thanks for the attention!