1. First results of proton spin tracking in a figure-8 ring
V.S. Morozov
JLab
F. Méot
BNL
MEIC R&D meeting, February 5, 2015
F. Lin

2. Ion Collider Ring
Using an earlier 1415 m version of the ion collider ring
Not a systematic study, none of the parameters have been optimized
Main goals:
Learn Zgoubi
Demonstration of some of the aspects of the figure-8 concept
Linear optics from Zgoubi

3. Spin-Tracking Perfect Figure-8 Ring
Ion collider ring without errors
Zgoubi sanity check
60 GeV/c protons
Three particles moving along the closed orbit with initially longitudinal, radial, and vertical spins
200103 turns = ~0.94 s
longitudinal
radial
vertical

4. Spin-Tracking Perfect Figure-8 Ring
Three particles start at IP with 0.2 mrad horizontal and vertical angles
Effect of the incoherent part of the resonance strength due to emittance
longitudinal
radial
vertical

5. Error Effect and Correction
One of the arc dipoles rolled by 0.2 mrad
Closed orbit without correction
Longitudinal spin without stabilization and with 1 longitudinal rotation

6. Error Effect and Correction
One of the arc quadrupoles misaligned vertically by 10 m
Longitudinal spin without stabilization and with 2 longitudinal rotation

7. Acceleration
From G = (59.9 GeV/c) to (60.4 GeV/c) in 2105 turns
Longitudinal spin in a perfect lattice G

8. Acceleration
Longitudinal spin with the 0.2 mrad dipole roll error without stabilization and with 5 longitudinal rotation

9. Conclusions Have a tool for spin tracking
World’s first (as far as we can tell) spin tracking in a figure-8 ring
Demonstrated some of the figure-8 features
Relatively easy to use
Straightforward model assumptions
Seems to work well on a million turn scale
Would probably be hard to go beyond a few seconds of beam time
Not entirely symplectic