1. SLAC Accelerator Development Program LHC Accelerator Research Tom Markiewicz OHEP Accelerator Development Review January 24-26, 2011

2. LHC Accelerator Research at SLAC Program began with a small LARP collimation task in 2003. Now: –8-9 areas of R&D & 2 year-long “Long Term Visitors” to CERN –~17 physicists, 4 MEs, 3 Ph.D. students, 1 postdoc + KLY + MFD 1 Ph.D. awarded → LARP Toohig Fellow –Leadership in US LARP & strong collaboration w/US labs + CERN LARP Deputy Leader, Accel Systems Manager, Toohig Chairman, …. Early LARP funded work expanded in FY08 with LARP call for “New Initiatives” to topics synergistic to SLAC’s traditional core skills and expertise –RF control, Electron Cloud studies, Feedback control, EM and beam physics calculations, collective effects, high intensity beam control,.. GAD funding was used to develop these programs to the point where LARP would fund the effort SLAC Accelerator Development Program Page 2

3. LHC Accelerator Research Tasks Tasks funded solely by LARP –Design & prototype a collimator for LHC’s collimation upgrade –Write Collective Effects sections of PS2 Design Report New tasks with seed funding from SLAC GAD for labor with Travel & M&S from LARP, transitioning to ~full LARP support –LHC Low Level RF –Feedback Control of Electron Cloud and Transverse Mode Coupled Instabilities in the SPS –LHC Crab Cavity Design –UA9 Crystal Collimation Experimentation in the SPS and LHC –Support of SLAC LTVs in LARP’s “Long Term Visitor Program” Synchrotron Light Monitor, Crystal Collimation, PS2 Studies, LHC Beam Commissioning Future tasks under discussion –Beam Physics Group involvement in HL-LHC Project –Role in any new LHC Hardware “Project” funded by DOE Crab, Collimation, Injectors have been discussed SLAC Accelerator Development Program Page 3

4. TaskPeopleDescription Rotatable Collimators G. Anzalone, Lew Keller, R. Rogers, S. Lundgren, T. Markiewicz, Jeff Smith, Liling Xiao + KLY+MFD Prototype RCs to CERN to test in SPS, HiRadMat Test Facility & LHC for LHC Phase II Collimation Upgrade LHC LLRFJohn Fox, Claudio Rivetta, Themis Mastorides, Dan van Winkle Adapt PEP-II LLRF Tools to LHC & Use for System Configuration, Study & Improvement Feedback to control Ecloud in SPS John Fox, A. Bullitt, O. Turgut, T. Mastorides, C. Rivetta, J. Olson Studies of FB to control Electron Cloud & TMC Instabilities in the SPS SPS Vacuum Ch to control Ecloud Mauro PiviEcloud Remediation via Grooved & Coated Vacuum Chambers Long Term VistorsAlan Fisher Uli Wienands LHC Synchrotron Light Monitor LHC Commissioning, PS2 Planning & UA9 LHC Crab CavityZenghai Li, Liling XiaoCrab Cavity Studies Crystal CollimationTom Markiewicz, Bob Noble, Marco Oriunno, U. Wienands Crystal Collimation experiments at SPS and LHC & future e-,e+ tests at SLAC PS2 StudiesU. Wienands, K. Bane, Lanfa Wang, Cho Ng, C. Rivetta, G. Stupakov Write “Collective Effects” sections of CERN White Paper for PS2 design LHC Accelerator Research Program Reference Table

5. Project Management At onset, each GAD-seeded task at SLAC was –Ranked highly by CERN’s liaison to LARP –Approved by the LARP Accelerator Systems Advisory Committee –Blessed by the LARP Advisory Board Progress is monitored through regular team work meetings Reporting occurs regularly at –Biannual LARP Collaboration meetings –Biannual DOE reviews of LARP –Numerous CERN, EuCARD, PAC/IPAC, special topic meetings,… Results are documented –3 Refereed Journals (PRSTAB, PL) –17 Conference Proceedings –4 CERN Reports SLAC Accelerator Development Program Page 5

6. Goals and Mission Relevance Overall –SLAC participation in a project at the ENERGY frontier –Extend SLAC’s core competencies to high current proton beams –Improve LHC performance to advance science Relevance: Tasks are integral part CERN plan –Regular emails from P. Baudenghein (BE-RF) praising LLRF work –SPS HF Transverse FB Proposal (W. Hoefle, E. Ciapella) “It is believed that this system can be built with strong support from US labs (SLAC/LBNL).” –Letters from S.Myers/R. Heuer to DOE on Upgrade Plans: Crab cavities, SPS HF Feedback, Collimation HIGH on priority list –HL-LHC Project Work packages explicitly incorporate SLAC work SLAC Compact crab cavity one of 3 options SLAC Elliptical cavity is only fallback option –Letters from LHCC requesting UA9 Crystal Collimation tests in LHC when ready SLAC Accelerator Development Program Page 6

7. LHC LLRF and Longitudinal Beam Dynamics Purpose: LHC non-linear beam dynamics-RF station simulation and system model. –The model captures engineering level implementation details. Results in 2009-2010: 1.The LLRF configuration tools have been used by the CERN BE-RF group to remotely commission the LLRF feedback loops of the RF stations during start up in both November 09 / February 10. –Tools reduced commissioning from 1.5 days/station to 1.5 hours/station. –Model based configuration adds consistency and reliability. –CERN BE-RF group have repeatedly expressed their support and proposes Continue work to test the 1-turn feedback functionality of the commissioning tools Expansion of the tools to control the smooth increase of the High Voltage and Klystron current with beam, from 450 GeV conditions to ramping/physics SLAC Accelerator Development Program Page 7

8. LHC LLRF and Longitudinal Beam Dynamics Results Continued 2.RF Noise Effect on Beam Diffusion Studies –Developed theoretical formalism relating the equilibrium bunch length with beam dynamics, accelerating voltage noise, and RF system configurations. –Conducted measurements that confirmed the formalism and models identified performance-limiting components –RF reference noise introduced by controller in mod/demodulation process –Intrinsic noise in the controller feedback boards set an allowable noise threshold for acceptable lifetime. 3.Predictions of beam longitudinal motion and RF station stability limits for future high current/higher energy LHC operations –Estimated longitudinal stability margin for 2011 operations. –Impact of future LLRF configurations on RF noise levels is being investigated. SLAC Accelerator Development Program Page 8

9. SPS Wideband Transverse Electron Cloud/TMCI Feedback Purpose: control Ecloud and TMCI effects in SPS via GHz bandwidth feedback –Technical formalism similar to 500 Ms/sec feedback implemented at PEP-II, KEKB, DAFNE –CERN, LBNL, SLAC (2 current, 1 graduated Stanford students+ staff) Approach & Results: 1.Measure electron cloud & TMCI vertical instabilities in SPS during Machine Development periods in 2009 and 2010 –Instability dynamics –Response of beam to driven motion Pickup and kicker studies using existing hardware 2.Modelling and dynamics estimation –Validation of LBNL Warp and Head-Tail models by comparisons to MD results simulations critical in estimating future conditions –Model dynamics of driven and free beam motion SLAC Accelerator Development Program Page 9

10. SPS Wideband Transverse Electron Cloud/TMCI Feedback 3.Development of linear coupled-oscillator model of internal bunch dynamics in progress –Use this to explore alternate feedback designs 4.Development of a “small prototype” functional feedback channel in progress a 4 GS/sec. beam excitation system for SPS –Modify existing SPS kicker system to synchronize with selected bunches –Use 4 Gs/sec. DAC hardware to drive noise sequences onto selected bunches –Use in 2011 MD periods Ongoing & Future –Identify critical technology options –Evaluate difficulty of technical implementation –Work toward “full prototype” for installation in next long down, then eventual final system SLAC Accelerator Development Program Page 10

11. LHC Crab Cavity Purpose: Develop crab cavity and coupler designs consistent with gradient, frequency and spatial contsraints of the LHC Results: 1.800 MHz Elliptical Cavity –2009 CERN CC Collaboration Baseline “Global Crab Scheme”: One cavity per beam located in IR4 RF area –Fully studied Modes, fields, R/Q, multipacting basic and alternative coupler designs –Stays as backup solution in HL-LHC Crab Cavity WP SLAC Accelerator Development Program Page 11

12. LHC Crab Cavity 2.400 MHz Half Wave Spoke Resonator Cavity –Designed for “Local Crab Scheme” One per beam per side per IR –Fully studied Modes, fields, impedance, R/Q, multipacting –Basis of AES, Inc. SBIR & Engineering Study –One of several designs in HL-LHC Crab Cavity WP SLAC Accelerator Development Program Page 12

13. UA9 Crystal Collimation Experiment at SPS Purpose: Extend core expertise in collimation of intense beams to crystal based primary collimators by participating in UA9 SPS crystal collimation experiment Results: SLAC Built Roman Pot: will house tracking detectors –LARP M&S, GAD Engineering LTV U. Wienands central to 2010 experimental program SLAC Accelerator Development Program Page 13

14. UA9 Crystal Collimation Experiment at SPS Preliminary results of Sept 2010 Run (to be sub. To Phys.Lett.) –Reduction of particle losses due to inelastic nuclear interactions of x35 Future –2011 runs in SPS –Planning for LHC experiment –Investigation with e-, e+ beams at FACET for collimation and as photon source SLAC Accelerator Development Program Page 14

15. LTV: LHC Synchrotron Light Monitor LTV Purpose: Educate & invigorate staff with challenges at the energy frontier while transferring knowledge to CERN –The SLM activity was a serendipitous result of 2009 “Long Term Visit” by A. Fisher after 2008 tunnel cryo-explosion Given startup pressures there was still much set up of SLM needed Results –In 2009 identify limitations in hardware, modify setup, test, etc. –In 2010 commission SLM with beam In routine use for observing beam size at injection, ramp, 3.5 TeV –Light from Lead Ions observed In routine use for monitoring abort gap SLAC Accelerator Development Program Page 15

16. LTV: LHC Synchrotron Light Monitor Impact: –Perhaps the most cost-effective contribution of LARP to CERN –Many complements (Bravin, Bruning, Myers) & hopes for continued involvement Future –Continued participation in further commissioning Improve agreement with wire scanners, longitudinal density monitor,.. –Possible development of a Digital Mirror Array based halo monitor at SSRL for LHC SLAC Accelerator Development Program Page 16 SLM in Abort Gap Cleaning Test

17. Past Funding and Future Needs SLAC Accelerator Development Program Page 17 FY2008200920102011 Funding (k$)N/A995961142 Program has transitioned to majority support by US LARP –2011 supports 50% of students and token fractions of staff Discussions with LARP underway on: –Proposal again is for ~1year of transition funding from SLAC GAD then LARP Beam Physics Group involvement in HL-LHC Project (~1 FTE) Response to CERN requests for more FTEs for Crab Cavity Design (~ 0.8 FTE) New LTV requests will be considered on case by case basis –LARP rules preclude salary support for senior LTVs

18. Collaboration and Technology Transfer Collaboration –LARP Labs (BNL, FNAL, LBNL) and CERN –Crab Cavity Collaboration (above & CEA, KEK, CNRS, STFC, U. Lancaster) –UA9 Collaboration (above & Imperial College, INFN, IHEP, JINR, PNPI) –Advanced Energy Systems, Medford NY Technology Transfer –LLRF Tools, SLM expertise, High Bandwidth Feedback expertise & hardware, Roman Pots, Specific Crab cavity Designs to CERN –Compact Crab Cavity design to AES SLAC Accelerator Development Program Page 18

19. Summary All programs presented are –part of CERN’s accepted operational model or are in CERN’s documented upgrade plans –Reviewed regularly by DOE as part of LARP GAD funding has been a well leveraged & cost effective We can do more with more funding –LARP cannot fund all requests it receives SLAC Accelerator Development Program Page 19