1. Update on MEIC Nonlinear Dynamics Work
V.S. Morozov
Teleconference on Nonlinear Dynamics
April 21, 2015
F. Lin

2. Arc CCB v3 Modified arc FODO lattice matched to regular arc FODO
Phase advance between SXT1 adjusted to 
Chromatic contribution x = and y = -6.3
Sextupole strengths required to compensate 100 units of x/y chromaticity: k2lsxt1/2 = 0.31/-0.66
Contributions to first-order geometric terms due to
finite value of x at SXT2
SXT1
SXT2 Re Im
h21000
0.04
h30000
-0.013
h10110
-0.18
h10020
1.85
0.09
h10200
2.04
-0.09

3. Complete Ring Lattice
Two identical CCBs integrated: one upstream and one downstream
Original (without CCBs) natural x/y chromaticities: -101 / -112
Resulting (with CCBs) natural x/y chromaticities: -121 / -120
The strongest quad in the CCB is ~50% stronger than a regular FODO quad
Resulting x/y betatron tunes: / (can be adjusted) IP

4. Chromaticity Compensation
W functions minimized at the IP and around the ring by tuning
the phase advance between the CCBs and the IP (using thin trombones)
the sextupole strengths in the CCBs
4 families (two –I pairs and two individual sextupoles) with k2l = -0.10, 0.23, 0.19, -0.37
residual linear x/y chromaticities: / -29.1
Residual chromaticities compensated using 2 additional sextupole families
24 sextupoles per family (12 sextupoles of each family in 12 adjacent FODO cells per arc)
90 phase advance between adjacent sextupoles of each family
resulting sextupole strengths k2l = 0.25, (in the arc with positive dispersion, polarities reversed in the other arc)
final ring x/y chromaticities adjusted to +1 / +1
no effect on the W functions outside of the 12 FODO cell blocks
before compensation
after W function adjustment
after residual chromaticity compensation

5. Higher-Order Chromatic Effects
Chromatic tune dependence
x,y < 0.02 within |p/p| < ~7p/p
Chromatic dependence of *

6. Conclusions and Outlook
Looks okay so far
Consistent with Min-Huey’s and Yuri’s earlier result
Further work
Tracking (have been having some issues with Elegant, will probably use PTC in MAD-X)
Optimization
60 FODO cells
Uninterleaved sextupoles for residual chromaticity compensation
Adjusting the upstream and downstream CCBs independently
Upstream CCB only (at the expense of chromatic beam smear at the IP)