1. Overview of the JLEIC Design Vasiliy Morozov for JLEIC Collaboration

2. JLEIC Collaboration
S. Benson, 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, F. Hanna, L. Harwood, T. Hiatt, Y. Huang, A. Hutton, K. Jordan, G. Kalicy, A. Kimber, G. Krafft, R. Li, F. Lin, F. Marhauser, R. McKewan, T. Michalski, V.S. Morozov, P. Nadel-Turonski, E. Nissen, 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, G.H. Wei, C. Weiss, R. Yoshida, H. Zhang, Y. Zhang - JLab, VA D.P. Barber - DESY, Germany Y. Cai, Y.M. Nosochkov, M. Sullivan - SLAC, CA S. Manikonda, B. Mustapha, U. Wienands - Argonne National Laboratory, IL P.N. Ostroumov, R.C. York - Michigan State University, MI S. Abeyratne, B. Erdelyi - Northern Illinois University, IL J. Delayen, C. Hyde, K. Park, S. De Silva, S. Sosa, B. Terzic - Old Dominion University, VA Z. Zhao - Duke University, NC A.M. Kondratenko, M. Kondratenko - Sci. & Tech. Laboratory Zaryad, Russia Yu. Filatov - Moscow Institute of Physics and Technology, Russia J. Gerity, T. Mann, P. McIntyre, N.J. Pogue, A. Sattarov - Texas A&M University, TX V. Dudnikov, R.P. Johnson - Muons, Inc., IL I. Pogorelov, G. Bell, J. Cary - Tech-X Corp., CO D. Bruhwiler - Radiasoft, CO

3. Outline Introduction JLab’s approach to the design
JLEIC design overview
Electron complex
CEBAF as a full-energy injector
Electron collider ring
Electron polarization
Ion complex
Ion injector complex
Ion collider ring
Ion polarization
Electron cooling
Detector region
Luminosity performance
Conclusions

4. Electron Ion Collider Recommendations in NSAC LRP 2015:
Continue existing projects: CEBAF, FRIB, RHIC.
“…a U.S.-led ton-scale neutrinoless double beta decay experiment”
“…a high-energy high-luminosity polarized EIC as the highest priority for new facility construction following the completion of FRIB”
“…small-scale and mid-scale projects and initiatives that enable forefront research at universities and laboratories”
EIC Community White Paper arXiv:

5. JLEIC Layout 2015 Electron complex CEBAF Electron collider ring
Ion complex
Ion source
SRF linac (285 MeV/u for protons)
Booster
Ion collider ring
Optimum detector location for minimizing background
3-12 GeV
8-100(400) GeV
8 GeV
SRF Linac &
2015
arXiv:
May 17 update:

6. Key Design Concepts
High luminosity: high collision rate of short modest-charge low-emittance bunches
Small beam size
Small β*  Short bunch length  Low bunch charge, high repetition rate
Small emittance  Cooling
Similar to lepton colliders such as KEK-B with L > 21034 cm-2s-1
High polarization: figure-8 ring design
Net spin precession zero
Spin easily controlled by small magnetic fields for any particle species
Full acceptance primary detector including far-forward acceptance
Beam Design
High repetition rate
Low bunch charge
Short bunch length
Small emittance
IR Design
Small β*
Crab crossing
Damping
Synchrotron radiation
Electron cooling

7. 12 GeV CEBAF as Injector Commissioned in Spring 2014
Operated at 12 GeV in Fall 2015
First Physics Run in Spring 2016
Exciting fixed-target science program
Fixed-target program compatible with concurrent JLEIC operations
JLEIC injector
Fast fill of collider ring
Full energy
~85% polarization
Enables top-off
Up to 12 GeV
to JLEIC

8. Electron Collider Ring Layout
Possible cost reduction by reusing PEP-II RF and vacuum pipe e-
R=155m RF
Spin rotator
CCB
Arc, 261.7
81.7
Forward e- detection and polarimetry IP
Tune trombone & Straight FODOs
Future 2nd IP

9. Electron Beam Electron injection from CEBAF Electron beam
Existing CEBAF electron gun
Two polarization state injection
fring / fCEBAF = MHz / 1497 MHz = 7 / 22
Electron beam
3 A at up to 7 GeV
Normalized emittance GeV
Synchrotron power density < 10kW/m
Total power up to 10 MW

10. Electron Polarization
Universal spin rotator
is made of sequence of solenoid and dipole sections,
makes the spin longitudinal at IP,
has longitudinal spin matching, and
ensures the same lifetimes for both polarization states.
Two highly polarized bunch trains maintained by the top-off injection.
Spin tracking simulations were performed. Benchmarking work is in progress.
Polarization Configuration
Spin tune scan using SLICKTRACK
Synchrotron sideband spin resonances suppressed compared to a racetrack
s=0.027
s=0.038
~ 7x,y
s=0.027
s=0.038
Spin tracking using ZGOUBI.

11. Ion Injector Complex Overview
Ion injector complex relies on demonstrated technologies for sources and injectors
Atomic Beam Polarized Ion Source (ABPIS) for polarized or unpolarized light ions, Electron Beam Ion Source (EBIS) and/or Electron Cyclotron Resonance (ECR) ion source for unpolarized heavy ions
Design for an SRF linac based on ANL design
8 GeV Booster with imaginary transition energy
Injection/extraction lines to/from Booster are designed

12. Booster 8 GeV/c Booster serves for Injection Design
Accumulation of ions injected from Linac
Cooling
Acceleration of ions
Extraction and transfer of ions to the collider ring
Injection
H- single pulse charge stripping at 285 MeV/u (0.22 – 0.25 ms long pulses ~180 turns)
Phase-space painting combined with electron cooling for heavy ions
Design
Circumference of 275 m
No transition energy crossing
Figure-8 shape for preserving ion polarization
extraction
RF cavity
Crossing angle:
75 deg.
Ekin = 285 MeV/u – 7.1 GeV/u
injection 40 5 -5
BETA_X&Y[m]
DISP_X&Y[m]
BETA_X
BETA_Y
DISP_X
DISP_Y

13. Ion Collider Ring Layout
Protons: 100 GeV/u (63 GeV/u in COM with 10 GeV e) Lead: 40 GeV/u (40 GeV/u in COM with 10 GeV e)
Super-ferric magnets (cos under consideration as risk mitigation)
R = m
Arc, 261.7 IP
disp. supp./
geom. match #3
geom. match #1
geom. match #2
det. elem.
disp. supp.
norm.+
SRF
tune
tromb.+
match
beam exp./
elec. cool.
ions
81.7
future 2nd IP
Polarimeter

14. Ion Polarization
Figure-8 concept: Spin precession in one arc is exactly cancelled in the other
Spin stabilization by small fields: ~3 Tm vs. < 400 Tm for deuterons at 100 GeV
Criterion: induced spin rotation >> spin rotation due to orbit errors
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
Polarized deuterons
Frequent adiabatic spin flips
Simulations in progress
n = 0
Start-to-end Zgoubi simulation of proton acceleration
𝜀 𝑥,𝑦 𝑁 =1 𝜇𝑚
𝜎 𝑥,𝑦 𝑐𝑜 =100 𝜇m
𝜈 𝑠𝑝 =0.01
𝑑𝐵 𝑑𝑡 =~3 T/min
Zgoubi simulation of proton spin flip

15. Multi-Step Cooling Scheme
Booster
(0.285 to 8 GeV)
ion sources
ion linac
collider ring
(8 to 100 GeV)
BB cooler
DC cooler
Ring
Cooler
Function
Ion energy
Electron energy
GeV/u
MeV
Booster ring DC
Injection/accumulation of positive ions
0.11 ~ 0.19
(injection)
0.062 ~ 0.1
Emittance reduction 2
1.1
Collider ring
Bunched Beam
Cooling
(BBC)
Maintain emittance during stacking
7.9
4.3
Maintain emittance
Up to 100
Up to 55
DC cooling for emittance reduction
BBC for emittance preservation against intra-beam scattering

16. High-Energy Bunched Electron Cooler
High-current magnetized electron beam maintains low ion beam emittances for high luminosity
SRF linac for acceleration and subsequent energy recovery for high energy efficiency
Circulator ring to relax requirements on the electron source and ERL
PARAMETERS
Electron energy
up to 55 MeV
Bunch charge
3.2 nC
Turns in circulator
~20
Current in CCR/ERL
1.5/0.075
Bunch repetition
476 MHz
Cooling section
60 m
Cooler solenoid
1 T
Magnetized Gun
Booster
50 MeV Linac Cryomodule
De-chirper
Chirper
Ion Beam
1 T Cooling Solenoid
Beam dump
Fast
Kicker
Circulator ring

17. Interaction Region Concept
Ion beamline
Electron beamline
Possible to get ~100% acceptance for the whole event
Central Detector/Solenoid
Dipole
Forward (Ion) Detector
Scattered Electron
Particles Associated
with Initial Ion
Particles Associated with struck parton
Courtesy of R. Yoshida

18. Detector Region IP e ions p e
Integrated detector region design developed satisfying the requirements of
Detection – Beam dynamics – Geometric match
GEANT4 detector model developed, simulations in progress IP e
Compton polarimetry
ions
forward ion detection
forward e detection
dispersion suppressor/
geometric match
spectrometers p
(top view in GEANT4) e
low-Q2 electron detection
and Compton polarimeter
Forward hadron spectrometer
ZDC

19. Crab Crossing Restore effective head-on collisions
Local compensation scheme
Set of crab cavities upstream and downstream of IP
Deflective crabbing
Demonstrated at KEK-B
Essential for high-luminosity LHC (collaboration opportunity)
Prototype developed at ODU
Simulations in progress

20. JLEIC Energy Reach and Luminosity
CM Energy (in each scenario)
Main luminosity limitation
low
space charge
medium
beam-beam
high
synchrotron radiation

21. JLEIC Parameters (3T option)
CM energy
GeV
(low)
44.7 (medium)
63.3 (high) p e
Beam energy 40 3
100 5 10
Collision frequency
MHz
476
476/4=119
Particles per bunch
1010
0.98
3.7
3.9
Beam current A
0.75
2.8
0.71
Polarization %
80%
75%
Bunch length, RMS cm 1
2.2
Norm. emittance, hor / ver μm
0.3/0.3
24/24
0.5/0.1
54/10.8
0.9/0.18
432/86.4
Horizontal & vertical β*
8/8
13.5/13.5
6/1.2
5.1/1.0
10.5/2.1
4/0.8
Ver. beam-beam parameter
0.015
0.092
0.068
0.008
0.034
Laslett tune-shift
0.06
7x10-4
0.055
6x10-4
0.056
7x10-5
Detector space, up/down m
3.6/7
3.2/3
Hourglass(HG) reduction
0.87
Luminosity/IP, w/HG, 1033
cm-2s-1
2.5
21.4
5.9

22. Conclusion JLEIC design is driven by and meets physics requirements
The overall risk is low
Key features:
High luminosity
High polarization
Full-acceptance detection
Minimal R&D necessary
Electron cooling
Magnet design
Current work
Key R&D
Detailed design
Performance and cost optimization

23. Backup

24. Electron Beam Dynamics
Linear optics
Chromaticity compensation
Momentum acceptance
Dynamic aperture
collaboration with SLAC

25. Super-Ferric Magnets 3 T Cost effective Fast ramp rate [1 T/s]
Cable-in-conduit conductor
Prototype winding

26. Ion Beam Dynamics Linear optics Chromaticity compensation
Momentum acceptance
Dynamic aperture
with errors and correction
10 seeds
collaboration with SLAC
±50