JLEIC - An Electron-Ion Collider Proposal at Jefferson Lab. Andrew Hutton On behalf of the JLEIC Design Team

Transcription

1 JLEIC - An Electron-Ion Collider Proposal at Jefferson Lab Andrew Hutton On behalf of the JLEIC Design Team

2 Overview of Jefferson Lab Jefferson Lab was created to build and operate the Continuous Electron Beam Accelerator Facility (CEBAF), a unique user facility for Nuclear Physics Mission is to gain a deeper understanding of the structure of matter Through advances in fundamental research in nuclear physics Through advances in accelerator science and technology CEBAF has been in operation since GeV Upgrade fully completed in 2017 and delivering beam to all four Halls Managed for DOE by Jefferson Science Associates, LLC (JSA) Jefferson Lab by the numbers: ~725 employees FY2016 Costs: $184.1M FY2017 Costs: $162.1M 169 acre site 72 buildings/trailers; 880k SF 1,530 Active Users 26 Joint faculty 562 PhDs granted to-date (200 in progress) Adams Institute, 18 January

3 Jefferson Lab FY2017 Budget ($162.1M) LCLS II Adams Institute, 18 January

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5 12 GeV CEBAF Upgrade Project is Complete! Total Project Cost = $338M Double maximum Accelerator energy to 12 GeV Ten new high gradient cryomodules Double Helium refrigerator plant capacity Civil construction and upgraded utilities Add 10 th arc of magnets for 5.5 pass machine Add 4 th experimental Hall D New experimental equipment in Halls B, C, D All KPPs (Key Performance Parameters) exceeded technical requirements, and the last KPP was completed 5 months ahead of schedule Project completed ~$2.4M under budget Project has been nominated for a DOE Secretary's Excellence Award CD-4 Project Completion Approved September 27, 2017 Adams Institute, 18 January

6 Nuclear Physics at Jefferson Lab Jefferson Lab acts as a large microscope! Probing the nucleus with electrons allows scientists to see inside matter. We want to know how ordinary matter is put together Atom Consists of a nucleus surrounded by electrons Nucleus Contains protons and neutrons and is 1000 times smaller than an atom. A scientific mystery: No quark is ever found alone If you try to pull two quarks apart the energy used will transform into a quark- antiquark pair Nucleon Three quarks bound by gluons. Adams Institute, 18 January

7 Nuclear Physics at Jefferson Lab Complex particle detectors Polarized electron source Adams Institute, 18 January

8 GlueX in Hall D New experiment to study quark confinement Commissioning complete Detector functioning well Production data-taking started Poised to discover exotic hybrid mesons Searching for the rules that govern hadron construction M. R. Shepherd, J. J. Dudek, R. E. Mitchell Co-authored by Indiana University experimenters and a JLab Scientist Adams Institute, 18 January

9 Jefferson Electron-Ion Collider JLEIC Adams Institute, 18 January

10 NSAC 2015 Long Range Plan Federal Advisory Committee Recommendation I The progress achieved under the guidance of the 2007 Long Range Plan has reinforced U.S. world leadership in nuclear science. The highest priority in this 2015 Plan is to capitalize on the investments made Recommendation II We recommend the timely development and deployment of a U.S.-led ton-scale neutrinoless double beta decay experiment Recommendation III We recommend a high-energy high-luminosity polarized EIC as the highest priority for new facility construction following the completion of FRIB Recommendation IV We recommend increasing investment in small-scale and mid-scale projects and initiatives that enable forefront research at universities and laboratories Adams Institute, 18 January

11 Realization of an Electron-Ion Collider Both Jefferson Lab and Brookhaven National Lab are proposing to build an electron-ion collider Jefferson Lab wants to add an ion complex to CEBAF BNL wants to add an electron complex to RHIC Only one, at most, will be built The present timeline is as follows: 2018 National Academy completes evaluation of the physics case ? DOE may consider CD-0, Approve Mission Need ? Down-select will/may occur 2022? Construction could start In the meantime, JLab and BNL are working together on common R&D Many other laboratories are collaborating This talk will only address the Jefferson Lab proposal JLEIC Adams Institute, 18 January

12 JLEIC Overview Energy range: E e : 3 to 12 GeV E p : 40 to GeV s: 20 to GeV (upper limit depends on magnet technology choice) Electron complex CEBAF Electron collider ring Ion complex Ion source SRF linac Booster Ion collider ring Fully integrated IR and detector DC and bunched beam coolers 2015 arxiv: Adams Institute, 18 January

13 Design Fundamentals High Luminosity Based on high bunch-repetition-rate and small bunch-charge of colliding beams High Polarization due to Figure-8 All rings are in a figure-8 shape critical advantages for both beams KEK-B reached > 2x10 34 /cm 2 /s IR Design Very small β* Crab crossing Beam Design High repetition rate Low bunch intensity Short bunch length Small emittance Damping Synchrotron radiation Electron cooling CEBAF provides 1.5 GHz bunch repetition rate as electron injector New ion complex is also designed to deliver high bunch repetition rate Spin precession in the left & right arcs of the ring are exactly cancelled Net spin precession (spin tune) is zero, thus energy independent Spin can be controlled & stabilized by small solenoids or other compact spin rotators Deuteron polarization can also be maintained (unique feature of Figure-8) Detection Capability Interaction region is design to support Full acceptance detection (including forward tagging) Low background Adams Institute, 18 January

14 Design improvements in the last year Fundamental design has been stable for more than a decade New electron ring: new magnets, same footprint Reaches 12 GeV 70 GeV Center-of-Mass 3 possible optics designs (FODO, TME, multiple bend achromat lattices) Same synchrotron radiation (10 kw/m, ~10MW) Strong cooling is back: circulator cooler ring >1 A current in the cooling channel Circulator ring, up to 11 turns, ~100 ma in ERL Enabled by significant progress in ERL cooler design and harmonic fast kicker development Higher stored ion current/bunch intensity: 500 ma 750 ma Up to 50% luminosity increase Seems OK with ion injector/dc cooling, Bunched cooling needs further study Enabled by development of ion beam formation scheme Enabled by very good results of dynamic aperture studies Smaller beta-star: β* y = 2 cm 1.2 cm ~60% luminosity increase Both detectors achieve Full-Acceptance and High-Luminosity Adams Institute, 18 January

15 Ion Injector Complex ion sources SRF linac cooling booster cooling collider ring Generate, accumulate & accelerate ion beams Covers all required varieties of ion species Delivers required time and phase space structure for matching with electron beam Ion linac (ANL) QWR HWR booster Crossing: 79.8 deg. RF cavity kicker extraction injection Quarter Wave Resonator Half-Wave Resonator Length (m) Max. energy (GeV/c) SRF linac ~ booster ~300 8 collider ring ~ (400) Adams Institute, 18 January

16 JLEIC Collider Rings Rings have same footprint, stacked vertically with horizontal crossing angle Ion ring Arc, Super-ferric magnets 81.7 future 2 nd IP ions IP Electron ring p Circumference m 2154 e Crossing angle degree 81.7 Lattice FODO FODO Dipole & quad m 8 & & 0.45 Arc, Forward e - detection IP Future 2 nd IP e - Cell length m Maxi dipole field T 3 ~1.5 SR power density kw/m 10 Transition tr Natural chromaticity -101/ /-123 Adams Institute, 18 January

17 High Luminosity: Electron Cooling ion sources ion linac DC cooler Bunched and DC cooler Booster (0.285 to 8 GeV) collider ring (8 to 100 GeV) Ring Cooler Function Ion energy Electron energy Booster DC Injection/accumulation of positive ions GeV/u 0.11 ~ 0.19 (injection) MeV ~ 0.1 Emittance reduction Collider DC Bunched Beam Maintain emittance during stacking 7.9 (injection) 4.3 Maintain emittance Up to 100 Up to 55 DC cooling for emittance reduction and maintenance during stacking BBC cooling for emittance preservation against intra-beam scattering Adams Institute, 18 January

18 Strong Cooling: Circulator Ring top ring: circulator cooling ring ion beam magnetization flip magnetization flip B < 0 B > 0 B > 0 B < 0 ion beam fast extraction kicker beam dump septum linac circulating bunches Magnetized injector septum fast injection kicker De-chirper bottom ring: energy recovery linac Electron energy MeV Bunch charge nc Up to 3.2 Turns in circulator ring turn ~11 Current in CCR/ERL A 1.5/0.14 Bunch repetition MHz 476 Cooling section length m 4x15 vertical bend Enabling technologies : Fast kickers, rise time<1 ns Magnetized source ~140mA Cooling solenoid field T 1 Fast kicker Re-chirper Magnetized source Adams Institute, 18 January

19 JLEIC Parameters (3T magnets) Center-of-Mass energy GeV 21.9 (low) 44.7 (medium) 63.3 (high) p e p e p e Beam energy GeV Collision frequency MHz /4=119 Particles per bunch Beam current A Polarization % Bunch length, RMS cm Norm. emittance, hor./vert. μm 0.3/0.3 24/24 0.5/0.1 54/ / /86.4 Horizontal & vertical β* cm 8/8 13.5/13.5 6/ /1 10.5/2.1 4/0.8 Vertical beam-beam parameter Laslett tune-shift x x x10-5 Detector space, upstream/downstream m 3.6/7 3.2/3 3.6/7 3.2/3 3.6/7 3.2/3 Hourglass(HG) reduction Luminosity/IP, w/hg, cm -2 s Adams Institute, 18 January

20 JLEIC Luminosity for Different Ion Dipoles LHC technology LHC Upgrade technology Adams Institute, 18 January

21 JLEIC R&D Areas: Jones Panel (February 2017) R&D activities Higher priority topical areas for EIC R&D funding Electron Cooling ECL 8 CTE Magnets MAG 6 CTE SRF R&D SRF 3 CTE Bridge design and R&D Executed on base, LDRD and selected EIC R&D funding Injectors R&D INJ 6 CTE Interaction Regions IRS 3 CTE Beam dynamics and diagnostics BDD 8 CTE Adopt mature technology where applicable Focus R&D on CTEs (critical technology elements), e.g. electron cooling Look at 4-5 year timeline Move technical readiness from low to medium in critical areas Properly identify high priority R&D (judgment call based on technology readiness and impact on performance and cost) Adams Institute, 18 January

22 Planned FY18 JLEIC R&D (1) Strong hadron cooling using a high-current ERL Magnetized electron source for strong hadron cooling Riad Suleiman Electron cooling simulation development Yves Roblin Development of a harmonic kicker to enable use of a circulator ring for strong hadron cooling Haipeng Wang SRF systems for an electron cooler Bob Rimmer Design of critical technologies for ERL-based electron cooler Steve Benson Validation of magnet designs by prototyping Complete and test a full scale suitable super-ferric magnet Tim Michalski Support of TAMU R&D IR magnet design verification Tim Michalski Development of IR magnet specifications for a prototype Tim Michalski IR FFQ prototype design Tim Michalski Adams Institute, 18 January

23 Planned FY18 JLEIC R&D (2) Crab cavity operation in a hadron ring Design and simulations of crab crossing and development of crab cavity specifications Participate in the first test of crab cavity operation in a hadron ring, SPS, at CERN Vasiliy Morozov Geoff Krafft Benchmarking of realistic EIC simulations Electron cooling experiment to benchmark continuous and bunched beam electron cooling simulations Further develop the design of the gear change synchronization and assess its impact on beam dynamics Yuhong Zhang Yves Roblin Benchmarking of ion spin tracking simulation tools Vasiliy Morozov Electron complex High-power fast kickers for high bandwidth (2 ns bunch spacing) feedback Bob Rimmer Operate the JLab CEBAF in the JLEIC injector mode Jiquan Guo Benchmarking of electron spin tracking simulations Vasiliy Morozov Adams Institute, 18 January

24 JLEIC Collaborators ANL & Northern Illinois University Ion injector design: linac, booster, electron ring as a large booster DESY, University of New Mexico & Cornell University Electron spin matching & electron spin tracking code Muons, Inc. & Cornell University Polarized ion source Old Dominion University Crab cavity design and crab crossing simulations Beam-beam code development Science and Technology Laboratory Zaryad & Moscow Institute of Physics and Technology Electron & ion polarization design and spin tracking SLAC Electron & ion chromaticity compensation, nonlinear dynamics optimization Detector region design, detector background Texas A&M University & LBNL Magnet design Prototype 3T super-ferric Collaboration with BNL strengthening Reaching out nationally and internationally Adams Institute, 18 January

25 JLEIC R&D Progress e-cooling simulation, beta-cool and new code development Bunched beam electron cooling at IMP Cooler design, preliminary design single-turn cooler Magnetized source, first magnetized beam in spring 2017 Fast harmonic kicker prototype tested successfully Short super-ferric prototype, mock up winding for 1.2m IR magnets, initial designs started ERL cavity, design done, prototype in progress Crab cavity, design started Spin tracking, p and e simulations validating Figure-8 Beam beam, GHOST code development progressing Adams Institute, 18 January

26 JLEIC R&D Highlights: Electron Cooling Institute of Modern Physics (IMP), CAS, China Collaboration between JLab and IMP (China) Electron cooling to date used a DC electron beam Cooling by a bunched electron beam is critical for JLEIC Proof-of-Principle Experiment: use an existing DC cooler, modulating the grid voltage of the thermionic gun to generate a pulsed electron beam (pulse length as short as ~100 ns) IMP has two storage rings, each has a DC cooler Thermionic gun cathode electrode Pulser DC cooler Adams Institute, 18 January

27 JLEIC R&D Highlights: Electron Cooling cooled ion bunches uncooled ion bunches Experimental data observed on BPMs Ring circumference Electron pulses First experiment: May 2016, bunched beam electron cooling observed for the first time Second experiment: November 2016, machine development (improving the beam diagnostics) Third experiment: April 2017, with improved electron pulses, data still being analyzed Adams Institute, 18 January

28 Magnetized Beam R&D Gun HV Chamber Gun Solenoid Beamline Photocathode Preparation Chamber Measuring beam mechanical angular momentum (beam magnetization) using slit and viewer screen method with 1511 G at photocathode 0 G Shield Tube Slit 1511 G 1511 G Viewer Screen Adams Institute, 18 January

29 Harmonic Fast Kicker R&D New! 11 scheme (Andrew Hutton/Dotson) 5-harmonics, copper prototype kicker Cavity, Yulu Huang, IMP/JLab PhD Thesis, 2016 New! end stub Ex & Ez vs z preliminary Vz=0 on beam axis for the 952.6MHz mode Improved symmetry in gap, Sarah Overstreet summer student project kV kick voltage (2.5mrad@55MeV) Baseline cavity design: six odd harmonics of 86.6MHz up to 952.6MHz + DC, one cavity design for all harmonics, one-pair for CCR High shunt impedance, per cavity Asymmetric inner conductor design for the 952.6MHz mode to minimize the beam loading effect Adams Institute, 18 January

30 JLEIC R&D Highlights: Super-Ferric Magnet Peter McIntyre Fabrication of 1.2 mockup winding at Texas A&M Adams Institute, 18 January

31 JLEIC R&D highlights: CIC cable Fabrication of long-length Cable-In-Conduit cable on perforated center tube Developed a custom cabler that maintains constant tension and twist pitch Completed 12 m cable Extensible to 125 m Adams Institute, 18 January

32 JLEIC R&D Highlights: Ion Polarization Figure-8 concept: Spin precession in one arc is exactly cancelled in the other Spin stabilization by small fields: ~3 Tm versus < 400 Tm for deuterons at 100 GeV Criterion: induced spin rotation >> spin rotation due to orbit errors Polarized deuterons are only feasible with Figure-8 design 3D spin rotator: combination of small rotations about different axes provides any polarization orientation at any point in the collider ring No effect on the orbit Frequent adiabatic spin flips Simulations in progress Start-to-end Zgoubi simulation of proton acceleration ε N x,y σ x,y = 1 μm co = 100 μm ν sp = 0.01 db dt = ~3 T/min n = 0 Zgoubi simulation of proton spin flip Adams Institute, 18 January

33 JLEIC R&D Highlights: Electron Polarization Universal spin rotator Sequence of solenoids and dipoles Makes the spin longitudinal at IP Has longitudinal spin matching Ensures the same lifetimes for both polarization states Two highly polarized bunch trains maintained by top-off injection Spin tracking simulations were performed, benchmarking in progress n s =0.027 n s =0.038 n s =0.027 n s =0.038 Spin tune scan using SLICKTRACK Spin tracking using ZGOUBI ~ 7 x,y Adams Institute, 18 January

34 EIC Final State Particles Electron beamline Beam Elements Beam Elements Beam elements limit forward acceptance Central Solenoid not effective for forward particles Adams Institute, 18 January

35 IR & Detector Concept Adams Institute, 18 January

36 Detector Region Integrated detector region design developed, satisfying the requirements of Detection Beam dynamics Geometric match GEANT4 detector model developed, simulations in progress IP electrons Compton polarimetry forward electron detection spectrometers forward ion detection dispersion suppressor/ geometric match ions Ions (top view in GEANT4) electrons low-q 2 electron detection and Compton polarimeter Forward hadron spectrometer ZDC Adams Institute, 18 January

37 Ion Interaction Region * x,y = 10 / 2 cm, D* = D * = 0 Three spectrometer dipoles (SD) Large-aperture final focusing quadrupoles (FFQ) Secondary focus with large D and small D Dispersion suppressor geometric match IP SD1 SD2 SD3 geometric match/ FFQ disp. suppression ~14.4 m 4 m D ~ 0 forward detection D = 0, D = 0 x, y < ~0.6 m middle of straight limit x and y Adams Institute, 18 January

38 Ion Beam Envelope & Trajectory for Δp/p = -1% Assuming beam momentum of 100 GeV/c, ultimate normalized x/y emittances xn / yn of 0.35/0.07 m, and ultimate momentum spread p/p of The horizontal size includes both betatron and dispersive components 2 nd focus IP Adams Institute, 18 January

39 Ion Beam Dynamics Linear optics Chromaticity compensation Momentum acceptance Dynamic aperture with errors and correction 10 seeds collaboration with SLAC ±50 Adams Institute, 18 January

40 Crab Crossing in Ion Ring Crab cavity locations near chromatic sextupoles seem adequate Crab 1 Crab 2 (2n+1)/( /2) (crab,ip) Δψ x 4.5 π 9.5 π Bunched Beam parameters # of particles 500 ε nx 0.35 m p/p σ s 1 cm Gaussian distribution 3 - sigma Adams Institute, 18 January

41 Electron IR Optics IR region Final focusing quads with maximum field gradient ~63 T/m Four 3m-long dipoles (chicane) with GeV for low-q2 tagging with small momentum resolution, suppression of dispersion and Compton polarimeter e - FFQs FFQs forward e - detection region Compton polarimetry region IP Adams Institute, 18 January

42 Forward e - Detection & Polarization Measurement Dipole chicane for high-resolution detection of low-q 2 electrons Compton polarimetry is integrated into interaction region design same polarization at laser as at IP due to zero net bending in between non-invasive monitoring of electron polarization Compton photon calorimeter n c Low-Q 2 tagger for low-energy electrons e - beam to spin rotator Low-Q 2 tagger for high-energy electrons Laser + Fabry Perot cavity Compton electron tracking detector Compton- and low-q 2 electrons are kinematically separated! Luminosity monitor e - beam from IP Photons from IP Adams Institute, 18 January

43 Detector Solenoid Effects Ions JLEIC Detector solenoid electrons Length 4 m (1.6 m-ip-2.4 m) Strength < 3 T Crossing Angle 50 mrad Effects e ring ion ring Coherent orbit distortion N Y Coupling Y Y Rotates crabbed beam planes at IP Y Y Generates vertical dispersion N Y Linear and non-linear optics perturbation Y Y Violation of figure-8 spin symmetry Y Y Adams Institute, 18 January

44 Collaborations and Plans Collaborations Existing core JLEIC collaborations: SLAC, ANL, LBL, ODU, Texas A&M Collaboration with BNL strengthening: identified common R&D elements Held a joint collaboration meeting in October 2017 at BNL, to be followed by one at JLAB in October 2018 Outreach in Europe and worldwide JLEIC Plans Pre-CDR ready for CD0 CDR ready for down-select and CD1 Adams Institute, 18 January

45 JLEIC Working Groups and Collaborations Ion injector complex / parameter development Todd Satogata Ion linac Brahim Mustapha (ANL) Ion and electron polarization Fanglei Lin / Vasiliy Morozov Electron cooler design Steve Benson Cooler magnetized electron source Riad Suleiman Simulations / Instability Yves Roblin / Rui Li IR / non-linear studies Vasiliy Morozov Crab crossing / Crab cavity Vasiliy Morozov / Jean Delayen (ODU) MDI / detector / Backgrounds Mike Sullivan (SLAC) / Rik Yoshida SRF / Fast kicker Bob Rimmer Engineering Tim Michalski Super-ferric magnets Peter McIntyre (Texas A&M) Adams Institute, 18 January

46 Conclusions The JLEIC fundamental design has not changed in more than 10 years The design is optimized to maximize initial performance and minimize technical risk The magnet technology to reach sqrt(s) of 140 GeV has been essentially demonstrated at LHC A rich collaborative and project specific accelerator R&D program is in progress with very encouraging results The EIC accelerator programs are encouraging international collaboration on accelerator R&D Adams Institute, 18 January