Medium-energy Electron Ion Collider (MEIC) Project at Jefferson Lab Vasiliy Morozov for MEIC design team Informal JLab seminar, December 9, 2015
Outline Introduction – EIC purpose – JLab’s approach to the design – MEIC design overview Electron complex – CEBAF as a full-energy injector – Electron collider ring – Electron polarization Ion complex – Ion injector complex – Ion collider ring – Electron cooling – Ion polarization Detector region – Detector design and integration – Forward detection – Crab crossing IPAC ’ 15, Richmond, May 5, 2015 2 Informal JLab seminar, December 9, 2015 2 2 2 2
MEIC Study Group A. Bogacz, P. Brindza, A. Camsonne, E. Daly, Ya.S. Derbenev, M. Diefenthaler, D. Douglas, R. Ent, Y. Furletova, D. Gaskell, R. Geng, J. Grames, J. Guo, L. Harwood, T. Hiatt, Y. Huang, A. Hutton, K. Jordan, G. Kalicy, A. Kimber, G. Krafft, R. Li, F. Lin, T. Michalski, V.S. Morozov, P. Nadel-Turonski, H.K. Park, F. Pilat, M. Poelker, R. Rimmer, Y. Roblin, T. Satogata, M. Spata, R. Suleiman, A. Sy, C. Tennant, H. Wang, S. Wang, C. Weiss, H. Zhang, Y. Zhang, Z. Zhao – JLab, Newport News, VA D.P. Barber – Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany A. Kondratenko, M. Kondratenko – Sci. & Tech. Laboratory Zaryad, Novosibirsk, Russia Yu. Filatov – MIPT, Dolgoprydny, Russia and JINR, Dubna, Russia P. N. Ostroumov – Argonne National Laboratory, Argonne, IL S. Abeyratne, B. Erdelyi – Northern Illinois University, DeKalb, IL A. Castilla, J. Delayen, C. Hyde, K. Park, B. Terzic – Old Dominion University, Norfolk, VA Y. Cai, Y.M. Nosochkov, M. Sullivan, M-H Wang, U. Wienands – SLAC, Menlo Park, CA J. Gerity, T. Mann, P. McIntyre, N.J. Pogue, A. Sattarov – Texas A&M Univ., College Station, TX IPAC ’ 15, Richmond, May 5, 2015 3 Informal JLab seminar, December 9, 2015 3 3 3 3
Electron Ion Collider Recommendations in NSAC LRP 2015: 1. Continue existing projects: CEBAF, FRIB, RHIC. 2. “ … a U.S.-led ton-scale neutrinoless double beta decay experiment ” 3. “ … a high-energy high-luminosity polarized EIC as the highest priority for new facility construction following the completion of FRIB ” 4. “ … small-scale and mid-scale projects and initiatives that enable forefront research at universities and laboratories ” EIC Community White Paper arXiv:1212.1701 IPAC ’ 15, Richmond, May 5, 2015 4 Informal JLab seminar, December 9, 2015 4 4 4 4
EIC Physics Highlights An EIC aims to study the sea quark and gluon-dominated matter – 3D structure of nucleons § How do gluons and quarks bind into 3D hadrons? – Role of orbital motion and gluon dynamics in the proton spin § Why do quarks contribute only ~30%? – Gluons in nuclei (splitting/recombining) § Does the gluon density saturate at small x? Need luminosity, polarization and good acceptance to detect spectator & fragments P. Nadel-Turonski IPAC ’ 15, Richmond, May 5, 2015 5 Informal JLab seminar, December 9, 2015 5 5 5 5
(M)EIC Realization Imagined • Shown as most optimistic (wishful) schedule • Start EIC construction after FRIB completion • Fixed-target 12 GeV CEBAF operations can continue throughout the construction period • Assumes endorsement for an EIC at the next (this) NSAC Long Range Plan (came true) • Assumes relevant accelerator R&D for down- select process done around 2016/17 • EIC Cost Review • CD3 is year when long-lead suggested a TPC of procurements can start, we think $1,500M for a generic this is FY20 at the earliest. EIC including detector • The EIC TPC and an assumed 15 • Design studies continue year of operations ($117M/yr in for reduction of the TPC FY15$) would be of similar cost as below this the CEBAF 4-6 GeV life cycle costs: • The relatively low $3.24B vs. $2.98B. technical risk of the MEIC design requires • Nuclear Physics can afford this. Year 12 Year 4 only minor investments ~ CD4 ~ CD3 in pre-R&D FY28? FY20? F. Pilat at Spring 2015 MEIC Collaboration Meeting IPAC ’ 15, Richmond, May 5, 2015 6 Informal JLab seminar, December 9, 2015 6 6 6 6
MEIC Design Parameters Energy – Full coverage of √ s from 15 to 65 GeV – Electrons 3 - 10 GeV, protons 20 - 100 GeV, ions 12 - 40 GeV/u Ion species – Polarized light ions: p , d , 3 He , and possibly Li – Un-polarized light to heavy ions up to A above 200 (Au, Pb) Space for at least 2 detectors – Full acceptance is critical for the primary detector Luminosity – 10 33 to 10 34 cm -2 s -1 per IP in a broad CM energy range Polarization – At IP: longitudinal for electrons, longitudinal or transverse for ions – All polarizations >70% Upgrade to higher energies and luminosity possible – 250 GeV proton, and 100 GeV/u ion IPAC ’ 15, Richmond, May 5, 2015 7 Informal JLab seminar, December 9, 2015 7 7 7 7
Design Strategy for High Luminosity The MEIC design concept for high luminosity is based on high bunch repetition rate CW colliding beams KEK-B already reached above 2x10 34 /cm 2 /s n n n n 1 2 1 2 L f ~ f Beam Design = * 4 ∗ ∗ πσ σ εβ • High repetition rate x y y • Low bunch charge “ Traditional” hadrons colliders • Short bunch length • Small number of bunches • Small emittance • Small collision frequency f • Large bunch charge n 1 and n 2 • Long bunch length • Large beta-star IR Design Damping • Small β * • Synchrotron Linac-Ring colliders • Crab crossing radiation • Large beam-beam parameter for the • Electron cooling electron beam • Need to maintain high polarized electron current • High energy/current ERL IPAC ’ 15, Richmond, May 5, 2015 8 Informal JLab seminar, December 9, 2015 8 8 8 8
MEIC Layout & Detector Location Cold Ion Collider Ring Two IP locations: (8 to 100 GeV) One has a new detector, fully instrumented Second is a straight-through, Warm Electron minor additional magnets Collider Ring needed to turn into IP (3 to 10 GeV) Considerations: Minimize synchrotron radiation – IP far from arc where electrons exit – Electron beam bending minimized in the straight before the IP Minimize hadronic background – IP close to arc where protons/ions exit IPAC ’ 15, Richmond, May 5, 2015 9 Informal JLab seminar, December 9, 2015 9 9 9 9
JLAB Campus Layout ~2.2 km circumference Ion-ring with 3 T super-ferric magnets E-ring from PEP-II Tunnel consistent with a 250+ GeV upgrade IPAC ’ 15, Richmond, May 5, 2015 10 Informal JLab seminar, December 9, 2015 10 10 10 10
CEBAF - Full Energy Injector CEBAF fixed target program – 5-pass recirculating SRF linac – Exciting science program beyond 2025 – Can be operated concurrently with the MEIC CEBAF will provide for MEIC – Up to 12 GeV electron beam new 5 – High repetition rate (up to 1497 MHz) cryomodules – High polarization (>85%) – Good beam quality up to the mA level new 5 cryomodules IPAC ’ 15, Richmond, May 5, 2015 11 Informal JLab seminar, December 9, 2015 11 11 11 11
Electron Collider Ring Layout Circumference of 2154.28 m = 2 x 754.84 m arcs + 2 x 322.3 straights Figure-8 crossing angle 81.7 ° Electron collider ring w/ major machine components e - 81.7 ° Arc, 261.7 ° Future 2 nd IP IP Forward e - detection IPAC ’ 15, Richmond, May 5, 2015 12 Informal JLab seminar, December 9, 2015 12 12 12 12
MEIC Electron Complex CEBAF provides up to 12 GeV, high repetition rate and high polarization (>85%) electron beams, no further upgrade needed beyond the 12 GeV CEBAF upgrade Electron collider ring design – Meets design requirements – Circumference of 2154.28 m = 2 x 754.84 m arcs + 2 x 322.3 m straights – Provides longitudinal electron polarization at IP(s) IP – Incorporates forward electron detection – Accommodates up to two detectors Electron Collider Ring Optics – Incorporates correction of beam nonlinearity – Reuses PEP-II magnets, vacuum chambers and RF Beam characteristics – 3A beam current up to 6.95 GeV β x (m), β y (m) D x (m) – Normalized emittance 1093 um @ 10 GeV – Synchrotron radiation power density 10kW/m – Total power 10 MW @ 10 GeV CEBAF and electron collider provide the required electron beams for the MEIC IPAC ’ 15, Richmond, May 5, 2015 13 Informal JLab seminar, December 9, 2015 13 13 13 13
e - Inj. from CEBAF to Electron Ring Electron injection bunch pattern (@6 GeV) from CEBAF with – f ring / f cebaf = 476.3MHz/1497MHz = 7/22 Injection Time and Beam Current vs. Energy – Two polarization states injection nominal – Existing CEBAF source gun Mid-cycle 1, inject the 1 st of every 7 buckets in the ring Impedance Bunch train, up polarization Synchrotron limit Bunch train, down polarization power limit 220 bunches, 3.233 µ s (I ave = 0.9mA @6GeV CEBAF) 14.69 ns, 68.05 MHz (7 ring buckets) 2ns, 476.3 MHz(ring freq.) 13 pC bunch Waiting for damping 12-700ms …… …… Waiting for 72.07 µ s 3416*10.5turns/476.3MHz=75.3ms 12-700ms, ~2 × e-ring damping time at different energy Transfer line 333.25m utilizes PEP-II LER dipoles (156) and quads (68) Injection scheme starts with PEP-II-like design – Dispersion free injection insertion – Septum + DC + RF kickers – Vertical injection because of greater dynamic aperture, absence of synchrotron oscillations and less IPAC ’ 15, Richmond, May 5, 2015 14 Informal JLab seminar, December 9, 2015 14 14 14 14
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