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LHC Accelerator Research at SLAC

LHC Accelerator Research at SLAC. T. Markiewicz SLAC Department Head (9/2008) LARP Accelerator Systems Division Leader (9/2008) LARP Collimation Leader (9/2005) LARP Rotatable Collimator Manager (9/2004). LARP LHC Accelerator Research Program. BNL - FNAL- LBNL - SLAC. Mission Statement:

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LHC Accelerator Research at SLAC

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  1. LHC Accelerator Research at SLAC T. Markiewicz SLAC Department Head (9/2008) LARP Accelerator Systems Division Leader (9/2008) LARP Collimation Leader (9/2005) LARP Rotatable Collimator Manager (9/2004) SLAC Annual Program Review

  2. LARPLHC Accelerator Research Program BNL - FNAL- LBNL - SLAC Mission Statement: • Make more LHC luminosity earlier • Use, develop and preserve unique US resources and capabilities in accelerator science and technology Accelerator Systems • Instrumentation • Collimation • Accelerator Physics Nb3Sn Magnet Systems Program Management • Beam and Hardware Commissioning • Long Term Visitors to CERN • Toohig Fellowships SLAC Annual Program Review

  3. History of SLAC as member of LARP SLAC Annual Program Review

  4. LHC AR at SLAC begins FY 2008 LHC AR at SLAC Advisory Committee • Alex Chao • TWM • Nan Phinney • Tor Raubenheimer • Uli Wienands SLAC Annual Program Review

  5. LHC Accelerator Research at SLAC Department Concept Participate in the LHC accelerator physics program: • by contributing in areas where SLAC has expertise & experience • enhance SLAC’s areas of core excellence: • collective effects, RF cavity design, collimation systems,… • educate SLAC staff on HEP’s only energy frontier machine • develop contact with next generation of accelerator physicists Use US LARP to coordinate & validate R&D plans and performance • NOT independent bi-lateral SLAC/CERN planning Use US LARP funding when possible, especially to leverage SLAC labor through M&S & Travel Use SLAC ARD funds as available for programs LARP cannot fund • ARD plan calls for ~8 FTEs for last half of FY08 SLAC Annual Program Review

  6. LHC-AR Tasks & People Funded by LARP in FY08 SLAC Annual Program Review

  7. LHC AR Tasks Proposed to LARP in FY08 & Accepted in LARP FY09 PlanFY08 Travel Funded by LARPFY08 Labor Funded by SLAC LARP budget allocation in FY09 still TBD!! SLAC Annual Program Review

  8. beam beam SLAC Concept for LHC Phase II Secondary Collimators Improve LHC Impedance and Collimation Efficiency 20 facets • beam spacing: geometrical constraint • Length available 1.47 m flange - flange • Jaw translation mechanism and collimator support base: LHC Phase I • 12 kW per jaw Steady State heat dissipation Glidcop Cu Mo Cu coolant supply tubes twist to allow jaw rotation Helical cooling channels 25mm below surface Hub area Cantilever Mo shaft @ both ends SLAC Annual Program Review

  9. Cu Jaw-Cu Hub-Mo Shaft Design 2mm shaft-jaw gap gives x5 improvement in thermal deformation over solid shaft-jaw design 1260 um  236 um (60kW/jaw, t=12min) 426 um 84 um (12kW/jaw, t=60min) Rather than Cu, Moly shaft improves Gravity sag x3: 200 um  67 um Thermal bulge 30%: 339 um  236 um SLAC Annual Program Review

  10. Status of RC Program • Jaw support & rotation mechanism COMPLETE (June 2007) • First full single jaw-hub-shaft unit COMPLETE • Preliminary tests indicate performance in accord with FEA to ~10% Final Jaw Braze 22 April 2008 Test Stand with External Heaters SLAC Annual Program Review

  11. RC Program Plans FY2008-FY2009 Plan: Complete RC1: • Finalize RF design • Test a few new concepts to simplify machining & brazing process • Order parts for 2-3 new jaws: copper mandrels, Mo shafts, Glidcop® jaws • Fab & braze 2-jaws, 4-supports, RF features in new vacuum tank • Metrology & vacuum tests • Mechanical motion tests on existing CERN system Ship to CERN in late 2009 for • SPS Transfer Line Robustness Test • LHC Beam Dynamics Test FY2010 and beyond If production decision made, provide engineering & commissioning support SLAC Annual Program Review

  12. Beam-Beam SimulationsAndreas Kabel (ACD) Goal • Benchmark beam-beam simulations codes with RHIC experimental data and evaluate the LHC beam-beam performance with long-range and head-on beam-beam compensation PLIBB code • PIC code, with MAD-X lattice input & Intra-beam scattering • for RHIC wire experiments and Electron lens Example: Beam Transfer Function for RHIC wire compensator vs. simulation SLAC Annual Program Review

  13. LHC LLRFJohn Fox , Claudio Rivetta, Themis Mastorides, Dan van Winkle Why SLAC? • PEP-II and LHC have same basic LLRF architecture • SLAC Group has much unique expertise and well developed set of software tools developed for PEP-II that can be used to configure the LHC system, study it and improve it Progress in 2008 • Three multi-weeks trips in April, June 2008 • SLAC software model configured for LHC and interfaced to control system Near Term Plans • 4 more person-weeks at CERN in FY08 for beam commissioning • Data from closed loop LLRF system with beam present will be compared against model and changes to LHC hardware configuration suggested • Expand model to include feedback & longitudinal emittance dilution • Eventually, develop theory & programs to model the long-term (24 hr) behavior SLAC Annual Program Review

  14. Sample LLRF Result Open Loop Xfer Function from time-domain excitation technique vs. model result (green) SLAC Annual Program Review

  15. Transverse RF Feedback in SPS to Control Beam Instabilities Produced by Electron Cloud EffectsJohn Fox, Jiajing Xu with LBL&CERN SPS Ecloud dynamics studies predict • Horizontal - coupled-bunch behavior • Vertical - single bunch-like instability 2008 Plan • Measure & quantify Ecloud effects on beam (instrumentation) • Compare measurements with E cloud/beam models ≥2009 Plan • Develop beam-FB simulation, evaluate possible feedback implementations. • Propose a technical implementation & develop Engineering Specs • Proof of principle experiments & technical R&D Eventual possible LHC construction project item SLAC Annual Program Review

  16. Transverse RF Feedback Measurements & HW • Measurements of x-y bunch structure in SPS will be made in August. • Initial measurements taken parasitically in June show a high frequency structure on the beam, but have instrumental issues Example of existing bunch-by-bunch FB (PEP-II, KEKB,..) SPS and LHC needs may drive new processing schemes and architectures SLAC Annual Program Review

  17. Experimentation to Investigate Possible Use of Crystals as High Efficiency Primary CollimatorsAndrei Seryi, Tom Markiewicz , Bob Noble, Shilun Pei, Jeff Smith, Gennady Stupakov Why SLAC: • Traditional expertise in collimation optics & devices for accelerators with high power density beams Where: • T980 at FNAL Tevatron - now through 2010(?) • CRYSTAL at the SPS – now through 2009 • Possible future e+/e- experiments at SLAC NLCTA and FACET Collaborators • RD22 team from CERN-Italy-Russia (1990-2007 SPS & H8 extracted line) • Fermilab team (1993-98, 2005-2007 Tevatron) • BNL Team (2005 RHIC) Status & Plans • Engineering plan for contributing “Roman Pot” • Data analysis & interpretation • Application to electrons and possible production of photon beams SLAC Annual Program Review

  18. SLAC Annual Program Review

  19. Grooved Vacuum Insertion Test at the SPS for Electron Cloud StudiesMauro Pivi, Lanfa Wang with LBL&CERN Electron cloud mitigation test chambers for SPS in prep • SLAC is manufacturing two grooved insertions • Metal folding & razor blades techniques for 1mm max. height • Installation Testing planned in summer 2008 Metal Folding: Form multiple folds. [EMEGA Company, USA] Brazed-up Assembly: Use individual razor type foil blades SLAC Annual Program Review

  20. LHC Crab CavityAndrei Seryi, Cho Ng, Zenghai Li, Liling Xiao Crab Cavities for each beam and each IP are needed for any luminosity upgrade requiring a larger crossing angle SLAC ILC Crab Cavity design experience and ACD computational tools immediately applicable Crab Cavity collaboration of all LARP labs, CERN and others (KEK, RAL, JLAB,…) SLAC responsibilities in areas of: • RF modeling of cavity & coupler design • HOM damping & Multipacting Studies • Thermal & Mechanical studies with TEM3P code and and ANSYS cross-check: • Crab and collimation • Overall coordination SLAC Annual Program Review

  21. SLAC Annual Program Review

  22. CERN PS2 (replacement for PS) studiesUli Wienands et al • Scope and budget are under discussion • Synergies with the FNAL MI upgrade • Interest from all 4 LARP labs 3 possible packages • Intensity effects, instabilities • RF system • Tracking, nonlinearities, space charge, halos, H- injection SLAC Annual Program Review LARP+LAUC DOE Review – 19-20 June 2008 Slide n° 22 LARP Accelerator Physics - W. Fischer

  23. Summary SLAC initially got involved with LHC accelerator research through LARP as a by-product of its Linear Collider collimator R&D SLAC expertise and experience is highly relevant in many other areas and effort is sought after by LARP and by CERN These expanded activities are just beginning, with good early results, supported both by LARP and by SLAC SLAC is prepared to participate in a US “LHC Luminosity Upgrade Project” & is participating in ongoing scope and schedule discussions SLAC Annual Program Review

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