1. Used PEP-II 476 MHz Cavities for MEIC Collider Rings
The Number of Cavities 36
Shunt Impedance ()
7 MW (V2/P) Q0
31000
Coupler Beta
3.5 ~ 4.0
Maximum Vgap
1 MV
Maximum Pfwd per Cavity
400 kW
The Number of Klystrons 15
Strategy:
Split cavities and klystrons in two rings with different cavity/Klystron ratio;
Build a couple of new cavities if necessary upfront;
Build new SC cavities in the future to gradually replace PEP-II cavities
Option 1: 952MHz SC cavities in both rings
Option 2: 476MHz SC cavities in e-ring, use PEP-II klystrons; 952MHz in i-ring with new klystrons

2. Top energy beam current (A)
RF stepping up options
CMS Energy (GeV)
Ring
Energy (GeV)
Cavity technology
Cav Num
Cav Pfwd (kW)
Total cavity Heat
Total Pfwd (MW)
Top energy beam current (A)
Cavity gradient MV/m 37 e
6.95
476 NC 12
393.6
1.1 MW
4.7
1.1
2.5
ion 50 24
118
877kW
2.8
0.5
2.4 61
9.3 30
428
2.7 MW
12.8
0.95
100
952 SC 4K 83
460W 1 10
69?
18?
476 SC 4K
12? 69
128 16
77.6
571W
1.24
9.7
78.4
422
686W
0.341
7.2

3. 476 MHz Cavities in Collider Rings for Bunch Length of 12 mm
(GeV) I
(A)
Vgap (MV)
Pforward (kW)
Pcavity (kW)
Cavity Number b
Klystron Number
Note
e Ring
9.8
0.9
0.78
418
87.5 36
3.8 18
9.3
0.946
0.79
428
90.1 30 15
8.7
1.0
0.80
433
92.0 24 12
6.95
1.1
394
89.6 6
5.0
1.2
0.69
280
67.4 5 3
Ion Ring 29
0.5
128 88
3.5 2
125 86 16 50
0.76
118 82
100
129 89 48

4. All SC cavities in 100GeV Ion Ring
𝑑𝑉 𝑑𝑡 =𝑉∙ 𝜔 𝑅𝐹 =1.1∙ 𝑉/𝑠
𝑃 𝑓𝑤𝑑 ∝1/𝑓 for SC cav, same Y
Cav Num
Pfwd (kW)
Total Pfwd (MW)
Coupling beta
Total cavity heat
Cavity gradient MV/m
Tuning angle (deg)
Loading factor Y
476 MHz 16
125
2.0
1.60e4
499W
7.5
-67.1
2.37 12
166
1.20e4
665W 10
748.5 MHz
106
1.27
0.975e4
521W
952 MHz 83
1.0
0.87e4
460W
476 warm 48
129
6.2
3.5
4.2MW
2.5
-44.6
0.99

5. All SC cavities in e Ring @12GeVdY
Common parameters:
Cavity number = 24
Bunch length = 12 mm
Operation Energy = 12 GeV
Beam current = A
Cav Num
Pfwd (kW)
Prefl (kW)
Cavity gradient MV/m
Total cavity heat dY
476 MHz 24
421.9
5.21
7.2
686 W
0.25
748.5 MHz
419.46
2.76
8.6
768 W
0.233
952 MHz
9.844
887 W