jleic - an electron-ion collider proposal at jefferson lab · jefferson lab fy2017 budget ($162.1m)...
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JLEIC - An Electron-Ion Collider Proposal at Jefferson Lab
Andrew Hutton On behalf of the JLEIC Design Team
Overview of Jefferson Lab
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• 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 1995
• 12 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)
Jefferson Lab FY2017 Budget ($162.1M)
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LCLS II
4
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 10th arc of magnets for 5.5 pass machine
• Add 4th experimental Hall D
• New experimental equipment in Halls B, C, D
12 GeV CEBAF Upgrade Project is Complete!
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CD-4 Project Completion Approved September 27, 2017
• 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
Nuclear Physics at Jefferson Lab
Atom
Consists of a nucleus
surrounded by electrons
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
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
Nucleus
Contains protons and neutrons and is
1000 times smaller than an atom.
Nucleon
Three quarks bound by
gluons.
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Nuclear Physics at Jefferson Lab
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Complex particle detectors
Polarized electron source
GlueX in Hall D
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• 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
Jefferson Electron-Ion Collider
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JLEIC
NSAC 2015 Long Range Plan
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
Federal Advisory Committee
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Realization of an Electron-Ion Collider
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• 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
• 2018 – 19 ? DOE may consider CD-0, “Approve Mission Need”
• 2019 – 21 ? 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
JLEIC Overview
2015
arXiv:1504.07961
• 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
Energy range:
Ee: 3 to 12 GeV
Ep: 40 to 100−400 GeV
√s: 20 to 65−140 GeV (upper limit depends on
magnet technology choice)
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Design Fundamentals
High Luminosity • Based on high bunch-repetition-rate and
small bunch-charge of colliding beams
• KEK-B reached > 2x1034 /cm2/s
• CEBAF provides 1.5 GHz bunch repetition rate as electron injector
• New ion complex is also designed to deliver high bunch repetition rate
Beam Design
• High repetition rate
• Low bunch intensity
• Short bunch length • Small emittance
IR Design
• Very small β* • Crab crossing
Damping
• Synchrotron radiation
• Electron cooling
High Polarization due to Figure-8 All rings are in a figure-8 shape
critical advantages for both beams
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
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Design improvements in the last year
• 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
• 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
• Smaller beta-star: β*y= 2 cm ➔ 1.2 cm • ~60% luminosity increase • Both detectors achieve “Full-Acceptance” and “High-Luminosity”
Enabled by significant progress in
ERL cooler design and harmonic
fast kicker development
Enabled by development of ion
beam formation scheme
Enabled by very good results of
dynamic aperture studies
Fundamental design has been stable for more than a decade
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Ion Injector Complex
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Length (m) Max. energy (GeV/c)
SRF linac ~121 0.2
booster ~300 8
collider ring ~2150 100 (400)
• Generate, accumulate & accelerate ion beams
• Covers all required varieties of ion species
• Delivers required time and phase space
structure for matching with electron beam
Half-Wave Resonator Quarter Wave Resonator
ion
sources
SRF
linac booster
collider
ring
cooling
cooling
Ion linac
(ANL)
QWR HWR
Crossing: 79.8 deg.
extraction injection
RF cavity kicker
booster
JLEIC Collider Rings
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• Rings have same footprint, stacked vertically with horizontal crossing angle
Arc,
261.7
IP ions
81.7 future 2nd IP
Ion ring
p e
Circumference m 2154
Crossing angle degree 81.7
Lattice FODO FODO
Dipole & quad m 8 & 0.8 5.4 & 0.45
Cell length m 22.8 15.2
Maxi dipole field T 3 ~1.5
SR power density kW/m 10
Transition tr 12.5 21.6
Natural chromaticity -101/-112 -149/-123
e-
Arc,
261.7
81.7
Forward e-
detection
IP
Future
2nd IP
Super-ferric
magnets
Electron ring
High Luminosity: Electron Cooling
Booster (0.285 to 8 GeV)
ion sources ion linac
collider ring (8 to 100 GeV)
Bunched and DC cooler DC cooler
Ring Cooler Function Ion energy Electron energy
GeV/u MeV
Booster DC
Injection/accumulation
of positive ions
0.11 ~ 0.19
(injection) 0.062 ~ 0.1
Emittance reduction 2 1.1
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
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Strong Cooling: Circulator Ring
Electron energy MeV 20−55
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
Cooling solenoid field T 1 Fast kicker
Magnetized
source
Enabling technologies :
Fast kickers, rise time<1 ns
Magnetized source ~140mA
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ion beam ion beam magnetization flip
top ring: circulator cooling ring
Magnetized injector beam dump linac
fast extraction kicker fast injection kicker
De-chirper Re-chirper
circulating bunches septum
vertical bend
magnetization flip
B < 0 B < 0 B > 0 B > 0
septum
bottom ring: energy recovery linac
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 40 3 100 5 100 10
Collision frequency MHz 476 476 476/4=119
Particles per bunch 1010 0.98 3.7 0.98 3.7 3.9 3.7
Beam current A 0.75 2.8 0.75 2.8 0.75 0.71
Polarization % 80 80 80 80 80 75
Bunch length, RMS cm 3 1 1 1 2.2 1
Norm. emittance, hor./vert. μm 0.3/0.3 24/24 0.5/0.1 54/10.8 0.9/0.18 432/86.4
Horizontal & vertical β* cm 8/8 13.5/13.5 6/1.2 5.1/1 10.5/2.1 4/0.8
Vertical beam-beam
parameter
0.015 0.092 0.015 0.068 0.008 0.034
Laslett tune-shift 0.06 7x10-4 0.055 6x10-4 0.056 7x10-5
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 1 0.87 0.75
Luminosity/IP, w/HG, 1033 cm-2s-1 2.5 21.4 5.9
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JLEIC Luminosity for Different Ion Dipoles
LHC Upgrade
technology
LHC technology
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JLEIC R&D Areas: Jones Panel (February 2017)
• 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)
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
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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
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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 Vasiliy Morozov
• Participate in the first test of crab cavity operation in a hadron ring, SPS, at CERN Geoff Krafft
• Benchmarking of realistic EIC simulations
• Electron cooling experiment to benchmark continuous and bunched beam electron cooling simulations Yuhong Zhang
• Further develop the design of the gear change synchronization and assess its impact on beam dynamics 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
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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
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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
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JLEIC R&D Highlights: Electron Cooling
Institute of Modern Physics
(IMP), CAS, China
DC cooler
Collaboration between JLab and IMP (China)
Thermionic gun
cathode
electrode
• 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
Pulser
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JLEIC R&D Highlights: Electron Cooling
• 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
Experimental data observed on BPMs cooled ion bunches uncooled ion bunches
Electron pulses
Ring
circumference
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Beamline
Gun Solenoid
Photocathode
Preparation
Chamber
Gun HV Chamber
Slit
Viewer
Screen
Shield
Tube
Magnetized Beam R&D
0 G
1511 G
Measuring beam mechanical angular momentum
(beam magnetization) using slit and viewer
screen method with 1511 G at photocathode
1511 G
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Harmonic Fast Kicker R&D
344kV 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, <1kW @344kV per cavity
• Asymmetric inner conductor design for the 952.6MHz mode to minimize the beam loading effect
Vz=0 on beam axis for the 952.6MHz mode
5-harmonics, copper prototype kicker Cavity, Yulu Huang,
IMP/JLab PhD Thesis, 2016
Improved symmetry in gap, Sarah Overstreet
summer student project 2017
New!
÷11 scheme (Andrew Hutton/Dotson)
Ex & Ez vs z
New! end stub
preliminary
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JLEIC R&D Highlights: Super-Ferric Magnet
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Fabrication of 1.2 mockup winding at Texas A&M
Peter McIntyre
JLEIC R&D highlights: CIC cable
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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
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
n = 0
Start-to-end Zgoubi simulation of proton acceleration
𝜀𝑥,𝑦𝑁 = 1 𝜇𝑚 𝜎𝑥,𝑦𝑐𝑜 = 100 𝜇m
𝜈𝑠𝑝 = 0.01
𝑑𝐵 𝑑𝑡 = ~3 T/min
Zgoubi simulation of proton spin flip
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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
~ 7x,y
ns=0.027
ns=0.038
Spin tracking using ZGOUBI
Spin tune scan using SLICKTRACK
ns=0.027
ns=0.038
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EIC Final State Particles
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Electron beamline
Beam Elements Beam Elements
Beam elements limit forward acceptance
Central Solenoid not effective for forward particles
IR & Detector Concept
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• Integrated detector region design developed, satisfying the requirements of
– Detection – Beam dynamics – Geometric match
• GEANT4 detector model developed, simulations in progress
Forward hadron spectrometer low-Q2 electron detection
and Compton polarimeter
Ions (top view in GEANT4) electrons
ZDC
IP electrons
ions forward electron
detection
Compton
polarimetry
dispersion
suppressor/
geometric match
spectrometers
forward ion
detection
Detector Region
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Ion Interaction Region
limit x and y
D’ ~ 0
~14.4 m 4 m
x , y < ~0.6 m
middle of straight
D = 0, D’ = 0
• *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/
disp. suppression FFQ
forward detection
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• 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 310-4
• The horizontal size includes both betatron and dispersive components
2nd focus
IP
Ion Beam Envelope & Trajectory for Δp/p = -1%
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Ion Beam Dynamics
• Linear optics • Chromaticity compensation
• Dynamic aperture
±50
with errors and correction
10 seeds
collaboration with SLAC
• Momentum acceptance
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Crab Crossing in Ion Ring
• Crab cavity locations near chromatic sextupoles seem adequate
Crab 1 Crab 2 (2n+1)/(/2) 8.9995 18.9995
𝛥𝜓𝑥(𝑐𝑟𝑎𝑏,𝐼𝑃)
4.5 π 9.5 π
Bunched Beam parameters
# of particles 500
εnx 0.35 m
p/p 3∙10-4
σs 1 cm
Gaussian distribution 3 - sigma
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Electron IR Optics
IP
e-
forward e-
detection region FFQs FFQs
Compton polarimetry
region
• IR region – Final focusing quads with maximum field gradient ~63 T/m
– Four 3m-long dipoles (chicane) with 0.44 T @ 10 GeV for low-Q2 tagging with small
momentum resolution, suppression of dispersion and Compton polarimeter
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Forward e- Detection & Polarization Measurement
nc
Laser + Fabry Perot cavity
e- beam
from IP
Low-Q2 tagger for
low-energy electrons
Low-Q2 tagger for
high-energy electrons
Compton electron
tracking detector
Compton photon
calorimeter
Compton- and low-Q2 electrons
are kinematically separated! Photons from
IP
e- beam to
spin rotator
Luminosity
monitor
• Dipole chicane for high-resolution detection of low-Q2 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
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Detector Solenoid Effects
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
JLEIC Detector solenoid
Length 4 m
(1.6 m-IP-2.4 m)
Strength < 3 T
Crossing Angle 50 mrad
Ions electrons
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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
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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)
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Conclusions
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• 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