Using crystals facilitates the LHC upgrade the LHC upgrade Victor Tikhomirov Institute for Nuclear Problems Minsk INP Outline The LHC luminosity upgrade Beam halo scraping by crystals Volume reflection of particles in bent crystals Volume reflection amplification by crystal axes Channeling capture increase by the crystal cut Conclusions Luminosity upgrade: Fifteen years of planning and R&D, followed by over 10 years of construction, should be followed by a comparable period of exploitation. Energy upgrade: What is better? The LHC upgrade need INP ssss Luminosity upgrade in more effective at M < 3.5 TeV ssss Statistics is too low for a clear separation among possible models at integrated luminosity of 100fb -1 ssss Thus, the luminosity upgrade have to be very effective INP ssss However luminosity increase will intensify the beam halo formation INP ssss Halo sources: beam physics and operational instabilities intra beam scattering scattering with residual gas synchrotron radiation collective instabilities INP ssss Collimation is used to scrape the halo ssss Crystals improve collimation efficiency ssss Crystals are used in both channeling and volume reflection regimes ssss Crystals bending ssss How it must look at the LHC crystal Proton absorption INP ssss Background reduction by channeling at FNAL INP Deflection of channeling protons reduce the background more than 4 times ssss Volume Reflection prediction A.M.Taratin and S.A.Vorobiev, Phys.Lett. A119 (1987) 425 and A.M.Taratin and S.A.Vorobiev, NIM in PR B26 (1987) 512 INP ssss Volume reflection CERN H8-RD22 experiment Sept 2006 channeling Volume reflection INP Volume capture ssss Volume reflection by crystal axes INP ssss Axes form reflecting planes INP ssss INP Protons are reflected from many crystal plane sets of one crystal ssss Reflection from many crystal planes increase VR angle 4 times - 1 INP ssss INP Reflection from many crystal planes increase VR angle 4 times - 2 ssss Typical distribution of multiple reflected protons ssss INP Reflection from different crystal planes allows to increase the volume reflection angle about 4 times ssss INP The capture probability can be increased by a plane cut ssss INP The cut diminishes the potential energy conserving the transverse kinetic one Transverse energy reduction by the cut - 1 ssss INP Transverse energy reduction by the cut - 2 Only 1-2% of protons avoid the transverse energy reduction by the cut ssss Protons are moved away from the high nuclear density regions Proton phase space transformation by the cut ssss INP Dechanneling suppression by the cut The cut decreases the dechanneling probability from 18 to 1-2% ssss A pair of crystals with cuts bent in orthogonal planes allows to deflect 99.9% of protons ssss INP The cut allows to increase the proton (nuclei) deflection efficiency and to decrease the accompanying proton absorption by 1-2 orders of magnitude ssss INP Conclusion: The LHC luminosity upgrade acquired new technical means which need further investigation