1. Update on MEIC Nonlinear Dynamics Work
V.S. Morozov
Teleconference on Nonlinear Dynamics
July 7, 2015
F. Lin

2. Complete Ring Lattice
Two identical CCBs, one upstream and the other one downstream of the IP
Optimal phase advances first obtained using thin trombones then implemented by adjusting phase advances of dispersion-free quadrupole sections
Betatron tunes: x = 25.22, y = 23.16 IP

3. MAD-X vs Elegant vs LEGO
Betatron tunes: x = 25.22, y = 23.16
No synchrotron motion
x = 23.4 m, y = 4.7 m, p/p = 60 GeV/c
p/p = 0
p/p = ~3p/p
p/p = 10p/p

4. Tracking in Elegant Betatron tunes: x = 25.22, y = 23.16
No synchrotron motion
x = 23.4 m, y = 4.7 m, p/p = 60 GeV/c
No issue with thin trombones in Elegant, ok to use for optimization
Thick trombones
Thin trombones

5. Frequency Map in x-p
Elegant, 1000 turns, no synchrotron motion, thick trombone case x y dr
x
y dr

6. Frequency Map in y-p
Elegant, 1000 turns, no synchrotron motion, thick trombone case x y dr
x
y dr

7. RF Parameters Proton Lead ion Energy 20 30 40 50 60 70 80 90 100 GeV/u
Rev Frequency
0.139
MHz
gamma
22.3
33.0
43.6
54.3
64.9
75.6
86.3
96.9
107.6
44.1
RF frequency
952.6
Current
0.50 A
Harmonic Number
6832
Circumference m
Momentum Compaction
6.413E-03
Energy Spread
2.00E-04
Bunch Length 12 mm
Phase Slip Factor
4.40E-03
5.49E-03
5.89E-03
6.07E-03
6.18E-03
6.24E-03
6.28E-03
6.31E-03
6.33E-03
5.90E-03
CavityActiveLength
0.157
Vpeak
2.64
4.93
7.05
9.08
11.09
13.06
15.03
18.93
17.90 MV
Cavity Insertion Length
1.91
Syn. Phase
0.00
degree
temperature 2 K
Vgap
0.88
1.23
1.17
1.14
1.19
1.25
1.21
1.18
BCS Resistance
8.91 nΩ
Gradient
5.58
7.83
7.46
7.22
7.55
7.96
7.71
7.52
7.59
MV/m
Residual Resistance
4.39
Syn. Tune
0.025
0.031
0.034
0.035
0.036
Surface Resistance
13.3
Forward Power
25.28
49.77
45.17
42.25
49.70
46.20
51.37
48.19
45.84
46.68 kW
Geometric Factor
217.01
Cavity Power
0.4
0.9
0.8
0.7 W
R/Q
Reflected Power
Qzero
1.63E+10
Coupling Beta
2.26E+05
Shunt Impedance
1.72E+06 MΩ δf
-28.7
-20.4
-21.4
-22.2
-21.2
-20.1
-20.8
-21.3
-21.1
kHz
Qext
7.22E+04
Qloaded
Active Cavity Number 3 4 6 8 9 11 14 16 15
Total RF Power
75.9
199.1
271.0
338.0
447.3
508.2
616.4
674.7
733.4
700.2

8. Tracking in MAD-X with Synchrotron Motion
Thick trombone case
Betatron tunes: x = 25.22, y = 23.16
Thin RF cavity, h = 6832, V = MV, s = 60 GeV/c
x = 23.4 m, y = 4.7 m, p/p = 60 GeV/c
p/p = 0
p/p = 3p/p
p/p = 10p/p

9. Conclusions & Outlook
LEGO, MAD-X PTC and Elegant all give very consistent results
Started analyzing non-linear behavior of the CCB scheme
RF parameters straightened out
Understand RF settings in both MAD-X and Elegant, currently running tracking with synchrotron motion in Elegant
Further work
Would like to understand what limits the CCB scheme: check resonance driving terms, play with phase advances, etc.
Betatron tune scan