Page 1 Review 09/2010 MEIC R&D Yuhong Zhang

Page 2 Review 09/2010 Outline MEIC R&D Issues View 1: EIC AC Recommendations View 2: MEIC Design Status View 3: Accelerator Technology Challenges Present Plan CASA/JLab Internal Resources External Collaborations Research Proposals Proposed Research Focuses Path Forward and Open Questions

Page 3 Review 09/2010 EIC Advisory Committee Recommendations Highest priority Design of JLab EIC High current (e.g., 50 mA) polarized electron gun Demonstration of high energy-high current recirculation ERL Beam-beam simulations for EIC Polarized 3 He production and acceleration Coherent electron cooling High priority, but could wait until decision made Compact loop magnets Electron cooling for JLab concepts Traveling focusing scheme (it is not clear what the loss in performance would be if it doesn’t work; it is not a show stopper if it doesn’t) Development of eRHIC-type SRF cavities Medium priority Crab cavities ERL technology development at JLab Only for very low ion energy, 12 GeV or less Most critical

Page 4 Review 09/2010 MEIC Machine Design Status Short term design goal (by next EIC AC meeting, 12/2010) We are committed to completing a MEIC design with sufficient technical details Short term technical Strategy Limiting as many MEIC design parameters as we can within or close to the present state-of-art in order to minimize technical uncertainty and required R&D Mid-term design goal (by next NSAC Long Range Plan, ~2013) A complete design supported with solid R&Ds & a zero-th order design report Unfinished design tasks (under the short term goal) Electron complex RF system Polarization lifetime by spin tracking Instability (feedback for multi-bunches) Ion complex Polarized and un-polarized ion sources SRF Linac & pre-booster (cooling, tracking) Design of big boosters RF system in boosters and collider ring Ion polarization (scheme, tracking) Electron cooling (cooler design, simulations) Instabilities, electron cloud Interaction region IR design, magnet, background Tracking studies and dynamics aperture Crab crossing and cavities Beam-beam simulations

Page 5 Review 09/2010 Accelerator Technology Challenges Level of R&D Low-to-Medium Energy (12x3 GeV/c) & (60x5 GeV/c) High Energy (up to 250x10 GeV) Challenging Semi Challenging Electron cooling Traveling focusing (for ion energies ~12 GeV) Electron cooling LikelyIR design/chromaticity Crab crossing/crab cavity High intensity low energy ion beam IR Design/chromaticity Crab crossing/crab cavity High intensity low energy ion beam Know-howSpin tracking Beam-Beam Spin tracking Beam-beam Interaction region design and limits with chromatic compensation Electron cooling Crab crossing and crab cavity Forming high intensity low energy ion beam Beam-beam effect Depolarization (including beam-beam) and spin tracking Traveling focusing for very low energy ion beam

Page 6 Review 09/2010 Three Most Outstanding R&D Issues Electron cooling of medium energy ions Effectiveness/efficiency of electron cooling at medium ion energy Design of circulator cooler ring, development of fast kicker High average beam current (ampere class) ERL Dynamics of electron beam in a circulator ring & long term space charge effect Dynamics of two coupled beams (cooling electrons and ions) Formation of high average current ion beams with high bunch repetition rate, small emittance and short bunch Negative (H -, D - ) ion sources and strip injections Ion SRF linac Low energy (~100 keV) long bunch (DC) electron cooling Space charge effect in pre-booster Ion polarization in a Figure-8 ring Demonstrate advantage of a Figure-8 ring for ion beams Polarized deuteron beam

Page 7 Review 09/2010 JLab MEIC Accelerator Design Team CASA (core team members) Alex Bogacz, Pavel Chevtsov (leaving), Slava Derbenev, Geoff Krafft, Rui Li, Vasiliy Morozov, Balsa Terzic, Byung Yunn, Yuhong Zhang one graduate student (Hisham Sayed) Approximately 4.35 FTE Expertise: mostly theoretical/computational, some operational (on linac & ERL) linear optics, recirculated linac, ERL, instability, collective effects polarization theory, electron cooling theory, beam-beam simulations New postdoc/staffs: up to 2 to 3 in the near future (pending grant applications) Within JLab RF system: Frank Marhauser, Bob Rimmer, Haipeng Wang Polarized electron source and photo-injector: Matt Poelker Expertise critically needed Proton/ion beams, ion source and linac, storage ring, ring-ring collider Situation changed significantly after arriving of two ion beam/collider experts: Fulvia Filat and Todd Satogata

Page 8 Review 09/2010 External Collaborations IR/detector designM. Sullivan (SLAC) Ion sourcesV. Dudnikov, R. Johnson (Muons, Inc) V. Danilov (ORNL) SRF Linac/Pre-boosterS. Manikonda, P. Ostroumov* (ANL) B. Erdelyi (NIU) Beam-beam simulationJ. Qiang (LBNL) (supported by SciDAC) Electron cooling simulationD. Bruhwiler (Tech X) (supported by SciDAC) PolarizationA. Kondratenko (Novosibirsk) Electron spin trackingD. Barber (DESY)

Page 9 Review 09/2010 Submitted Research Proposal Proposal Title: Advanced Electron Ion Collider Design Program: Research and Development for Next Generation Nuclear Physics Accelerator Facilities (DOE Financial Assistance Funding Opportunity Announcement LAB ) Amount request: $4.5M over 3 years Status: Pending (initial feedback is positive) Project 1.Collider Ring Design 2.Numerical Simulation of Beam-Beam and Other Beam Dynamics 3.Development of a Spin Manipulation and Stabilization System For a Future Electron-Ion Collider 4.Development of Advanced Electron Cooling Systems

Page 10 Review 09/2010 Present Research Focal Points We will concentrate R&D efforts on the most critical tasks (proposed Feb. 2010) Focal Point 1: Forming high-intensity short-bunch ion beams & cooling Sub tasks: Complete design of the RF linac and pre-booster Ion bunch dynamics and space charge effects (simulations) Led by Peter Ostroumov (ANL) Focal Point 2: Electron cooling of medium-energy ion beam Sub tasks: Electron cooling dynamics (simulations) Complete design of the ERL-based circulator cooler Dynamics of cooling electron bunch in an ERL circulator ring Focal Point 3: Beam-beam interaction Sub tasks: Include crab crossing and/or space charge Include multiple bunches and interaction points Including space charge effect for low ion energy

Page 11 Review 09/2010 Path Forward and Strategy Short term by next EIC AC Meeting ~12/2010 Complete a conceptual design with sufficient technical details Plug holes and fill design gaps Conservative position on accelerator technology design completeness over technology innovation & collider performance Intermediate term by next NSAC RLP ~ st Half Design optimization (still technology conservative) Type I R&D: issues which will improve creditability of design and save cost 2 nd Half Design optimization (modest technology forward looking) Type II R&D: issues which will improve collider performance and save cost Long term by ZDR/CDR ~2016 Design optimization, technology aggressive Type III R&D: issues for maximum pay-off for best collider performance

Page 12 Review 09/2010 Open Questions What are the most important R&D issues? Given present resources and expertise, how we prioritize these critical R&D topics? What are the reasonably achievable goals for Short term R&D, by next EIC AC meeting, Feb Intermediate term R&D, by next NSAC LRP, 2013 What expertise we should add to the local design team? What new external collaborations we should seek to establish?