Summary of Accelerator Systems New Initiatives Parallel Session

1. US LHC Accelerator Research Program BNL - FNAL- LBNL - SLAC Summary of Accelerator Systems New Initiatives Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC

2. 10 New Initiatives-Thursday 1:30PM • While money is always tight and FY08 in particular has been allocated with little wiggle room, consensus is that we try to improve LARP system to: • Introduce projects early enough to get input from relevant parties: lab partners, CERN, home institution • Consider how to have LARP manage, or incubate, LHC projects taken on as part of the lab’s base program • Give management more time to request new monies and/or manage existing funds New Initiatives Summary - T. Markiewicz

3. Irradiation Damage in LHC Beam Collimating MaterialsN. Simos (BNL) & N. Mokhov (FNAL) • Request: • Fund a CONTINUING EFFORT in irradiation studies • 0.3 BNL senior FTE/year plus $180k/year for beam time • Funding requested for FY08, FY09, FY10 • Deliverables: • Continued studies of physical properties of already irradiated Phase I and Phase II materials • Extension of materials to • Exotic composites (Diamond-Metal, Carbon-NanoFiber-Cu, etc.) • SC Magnet Materials • Crystals • Neutron & Gamma studies of materials • Study of physical properties as function of radiation dose • integrated software package (MARS + Non-linear structural dynamics code) for reliable prediction of radiation effects, benchmarked in dedicated measurements • Laser-based shock (high-strain rate) effects on irradiated materials New Initiatives Summary - T. Markiewicz

4. LHC optics measurement, modeling, and correction with Model Independent Analysis (MIA)Yiton Yan (SLAC) • Description: • MIA is a series of MATLAB programs that has been proven robust for PEP-II optics correction. • MIA, via an analysis of turn-by-turn BPM orbit data and an auto SVD-enhanced fitting process, brings the real hardware storage ring to a computer -- the virtual machine that matches the real machine in optics. • MIA then figures out a better virtual machine (lower beta beat, lower coupling, lower dispersion beat, etc) for the real machine to emulate and calculates tuning “knobs” to change real machine to the model • MIA has helped PEP-II overcome many optics improvement milestones and has had major contributions for PEP-II luminosity enhancement. • Goals: • Adapt MIA to LHC • Strong synergy with AC Dipole program New Initiatives Summary - T. Markiewicz

5. New Initiatives Summary - T. Markiewicz

6. MIA Resource Request • Manpower • Y. Yan: ½ FTE both for FY 2008 and FY 2009. • Travel • 2 trips to BNL in FY2008 • LTV (3 month) visit to CERN at machine startup • LTV (6 month) visit to CERN in 2009 • Deliverables: • Modify MIA for LHC • Identify BPM problems via MIA analysis of LHC optics at startup • Develop LHC optics model and start LHC optics improvement (beta beat and coupling correction, etc.) with MIA (2009 goal) • Modify MIA for RHIC and benchmark at RHIC at BNL • Long term future of continued study of LHC optics via MIA at SLAC with occasional visits as required New Initiatives Summary - T. Markiewicz

7. Impedance and Stability at the LHCKarl Bane (SLAC) • to build on what CERN has already done, and to collaborate with • them on solving impedance/instability questions for the LHC • preliminary goal: try to understand SPS impedance/measurements; • eventually work to LHC • to commit to 0.5 FTE in 2008 • I would go for 3 months to CERN • the other 3 months would be done by me and/or others, working • here and/or at CERN • others expressing interest in participating – Z. Li, C. Ng, R. Warnock, • S. Heifets, G. Stupakov, … • it is envisioned that this work would continue past 2008 New Initiatives Summary - T. Markiewicz

8. Proposed Impedance Tasks • LHC • collimator impedance calculations, low frequency resistive wall impedance questions (RA, EM) • complete impedance budget – to get realistic impedance of ring (FZ) • stability simulations – longitudinal, transverse; macroparticle, linearized Vlasov, etc; simulate experiments with feedback (EM) • clearing efficiency of collimators when including wakefields; puzzle • of 10 second tails in scraping tests (FZ, RA) • effect of impedance on Landau damping (FZ) • impedance measurements planning (FZ) • coupled bunch instabilities at LHC – participate in shifts (EM) • SPS: • puzzle in longitudinal and transverse impedance measurements (EM) • fast vertical single bunch instability at injection (EM) • simulations -- compare with measurements (ES) • LHC upgrade: • intensity limits (FZ) New Initiatives Summary - T. Markiewicz

9. Synchrotron-Light Monitors,Beam-Loss Monitors,Luminosity Dither FeedbackAlan Fisher (SLAC) • SLM Collaboration • Hutchins is very interested in having an experienced SLM person to devise and execute a detailed commissioning procedure. • The remote control room at SLAC then allows an expert in a different time zone to respond to concerns from the CERN control room. • Collaboration on the future capabilities may follow. • BLMs • Dehning was very interested in having an outside look at their evaluation of system reliability. • He asked me to read a 2005 PhD thesis on the reliability of the BLM system. I have done so and have begun discussing details with him. • This is likely to lead to further collaboration as the system is commissioned. New Initiatives Summary - T. Markiewicz

10. Instrumentation Commissioning (continued) • Luminosity Monitor Dithered Feedback • Bill Turner of LBNL originally intended a dither for LHC using their luminosity monitor. • As an LHC upgrade we return to this idea, proposing a feedback based on PEP’s scheme. • To begin: which magnets and power supplies are suitable? • Participants: Fisher, Wienands, Sullivan (SLAC); Turner, Ratti, Matis (LBNL); Kozanecki (Saclay) • Budget (for SLAC/LARP only) • depends on LHC commissioning and on coordination with CERN. • FY 2008 • %FTE: 5% • Travel: 5 k$ • One trip for 1 to 2 weeks • FY 2009 • %FTE: 40% • Long-term visitor program • Travel: 10 k$ • 2 trips in addition to LTV New Initiatives Summary - T. Markiewicz

11. LHC Remote Control Area at SLAC New Initiatives Summary - T. Markiewicz

12. Analysis of Phase-Advance DataWalter Wittmer (SLAC) • At PEP-II, phase-advance data is used routinely to assess state of the optics (ß beat, coupling) • Turn-by-turn, 1024 turns, for each BPM • Phase and amplitude extraction in RInQ BPM processors. • Extract ß functions by comparison with model • • LHC will have an AC Dipole & can take similar data • • The tricky part: • – Dealing with 90°/cell (per BPM) phase advance • (Wienands et al., EPAC 2002) • – Dealing with imperfect data (noise, non-reading BPM, ...) • • At PEP-II this is packaged in the online system • – Fortran/C, Oktave (Matlab) prototype exists also. New Initiatives Summary - T. Markiewicz

13. Phase Advance Measurement Proposal • Visit (in FY08) to CERN by Wittmer • – Explore possibility of bringing our software to LHC • – Explore possibility of collaborating with Fartoukh &Tomas to apply their methods to PEP-II • • $3k in FY08 for this visit • • Follow-on Request for FY09 to be presented at next CM. • – Actual software port & installation. • • BNL / Fermilab has an AC-Dipole effort in LARP. We would like to explore joining with them. New Initiatives Summary - T. Markiewicz

14. Study of Beam-Beam Limit in Hadron CollidersYunhai Cai and Robert Warnock (SLAC) • Beam-Beam lifetime (T. Sen, A. Kabel ) • Parasitic collision • Wire compensation (W. Fischer) • Electron lens compensation (V. Shiltsev) • Emittance growth due to beam-beam collisions • Strong-weak, gives too small values • Strong-strong • Gives unreliable values due the numerical noise • Predicts a beam-beam limit that is a factor of ten larger than in the electron machine New Initiatives Summary - T. Markiewicz

15. Improving Strong-Strong Codes • Numerical noise in PIC codes • Macro particle representation of density • Discrete Poisson solver • Vlasov-Poisson approach to eliminate the noise due to macro particles • 1D code for microwave instabilities was proven very effective • 2D beam-beam code was developed by Andrey Sobol. Ported • to computers at SLAC • A new idea to solve Vlasov, with some advantages of PIC method (lower cost , while keeping low noise) • Forward tracking (similar to macro particles) • Smoothing by interpolation of data at quasi-random sites • Probability conserving algorithm at data sites New Initiatives Summary - T. Markiewicz

16. Goal and Plan • Compare noise between PIC and Vlasov codes and quantify any improvements • To understand emittance growth due to beam-beam in hadron machines at least in relative terms within two years • Benchmark the codes against experiments in Tevatron and RHIC, understand the emittance growth at 10% level within five years and compare to the result from LHC • Resource: • 2 FTE for two years possible extension to five years • At least one new FTE (post-doctoral) • Maybe a dedicated cluster later New Initiatives Summary - T. Markiewicz

17. Beam FDR BDR Optical Diffraction Radiation Monitor • Radiation emitted when a charged particle passes in the vicinity of a conducting target. • Two cones (angle ~ 2/γ ) of radiation in the forward and backward direction • Key parameters: the impact parameter, beam energy and wavelength of radiation • Main advantage: Non-invasive • Observables • Near field (at or near target) intensity • Polarization • Frequency spectrum • Far field angular distribution • Interference • Extract • Beam size • Beam position • Beam divergence • Energy New Initiatives Summary - T. Markiewicz

18. Optical Diffraction Radiation Pre-ProposalTanaji Sen - Fermilab • Design ODR setup in the Tevatron – E0 preferable. • Develop a collaboration with US labs and CERN • Present proposal to the LARP collaboration for funding a LARP task (April 2008) • Proceed with experiments • Develop ODR facility for the LHC • Determine potential for future machines: muon collider, ILC,… New Initiatives Summary - T. Markiewicz

19. LLRF system - Beam dynamics models for LHCImpedance Control Architectures, Effects of technical implementation on accelerator performanceJ.D. Fox,1 C. Rivetta,1 T. Mastorides,1 D. Van Winkle,1T. Linnecar, 2 P. Baudrenghien,2 J. Tüchmantel2SLAC, CERN • AB Dept., CERN, SLAC mutual interest. • Propose a concurrent plan of activities including the modeling, analysis and evaluation of LHC RF station performance and beam stability and performance. • CERN request - Adapt the PEP-II RF station identification configuration tool to the LHC LLRF task. Optimal situation, develop tool November 07 for use in RF station commissioning. • Goals • Expand existing RF station models and include in the simulation the low-mode coupled bunch beam dynamics. • Quantify the effect of LLRF imperfections and noise in the LLRF implementation on the beam stability and longitudinal dilution. • Specify necessary performance for next-generation LLRF systems. • Important for LLRF systems in future facilities and up-dates. New Initiatives Summary - T. Markiewicz

20. LLRF Task Resource Request • Phase I (FY2008) • 1 FTE Junior, 0.2 FTE Senior Salaries to be covered by LARP. • 0.5 FTE Senior Salary, covered by SLAC. • Travel: 3 visits x 2 weeks/visit to CERN. • RF Stations Configuration Tools - Commissioning Tasks • 0.25 FTE Senior Salary to be covered by LARP Commissioning. • Travel: 2-3 months at CERN, to be scheduled by CERN needs. • Phase II (FY2009) (duration 1 year post Phase I) • 0.75 FTE Junior, 0.4 FTE Senior Salaries to be covered by LARP. • 0.35 FTE Senior Salary, covered by SLAC. • Travel: 3 visits x 2 weeks/visit to CERN. • M&S: 15K$ in addition to SLAC R&D contribution for evaluation modules and critical sampler components. New Initiatives Summary - T. Markiewicz

21. Block diagram of the prototype damping system tested at PSR. Control of E-Cloud Instabilities in the SPS • Feasibility study of feedback control of e-cloud instabilities in the SPS • Participate in SPS instability/e-cloud studies • Evaluate feasibility of feedback control (rather than grooves,coatings, scrubbing,..) • Propose a solution one year from now (if all goes well) • LARP Team: CERN: • John Byrd (LBNL) Gianluigi Arduini • Miguel Furman (LBNL) Wolfgang Hoefle • John Fox (SLAC) • Mauro Pivi (SLAC) Budget request: $75k New Initiatives Summary - T. Markiewicz

22. SLAC Component of SPD E-Cloud Support Request • Participation in E-Cloud studies at the SPS • Adaptation of SLAC’s transient analysis codes to SPS and LHC data structures • Analysis of SPS and LHC beam dynamics studies, comparisons with Ecloud models, participation in LHC transverse feedback system commissioning • Technical analysis • • Bunch-by-bunch dipole control (existing systems, possible enhancements or upgrades) • • Single bunch control (wideband, within bunch Vertical plane) • Resources • Consistent with J. Byrd request for Phase I • • 0.1 FTE Staff (J. Fox) • • 0.2 FTE Graduate Student (J. Xu) • Based on the Phase I results, a more detailed Phase II proposal in 2009 would • • develop the detailed requirements for a new wideband feedback system architecture • • key proof-of-principal technology R&D on GHz bandwidth (e.g. 2.5 GS/sec.) processing New Initiatives Summary - T. Markiewicz