Preliminary design parameter for SuperKEKB
|
|
High Current Scheme |
Nano Beam Scheme |
| Energy |
E (GeV) (LER / HER) |
3.5 / 8 |
4 / 7 |
| Horz. emittance |
ε x (nm) |
18 / 24 |
3.2 (2.7) / 2.4 (2.3) |
| Vert. emittance |
ε y (pm) |
240 / 90 |
12.8 / 8.2 |
| coupling |
κ (%) |
1 / 0.5 |
0.4 / 0.35 |
| Horz. β function at IP |
β *x (mm) |
200 / 200 |
32 / 25 |
| Vert. β function at IP |
β *y (mm) |
3 / 6 |
0.27 / 0.41 |
| Horz. beam size at IP |
σ *x (μm) |
69 / 60 |
10.2 (10.1) / 7.8 (7.6) |
| Vert. beam size at IP |
σ *y (μm) |
0.85 / 0.73 |
0.060 (0.059) / 0.060 (0.059) |
| bunch length |
σ z (mm) |
5 / 3 |
6.0 (4.9) / 5.0 (4.9) |
| electron bunch population |
ne |
5.25 ×1010 |
6.5 ×1010 |
| positron bunch population |
np |
12 × 1010 |
9.0 × 1010 |
| Beam Current |
I (A) |
9.4 / 4.1 |
3.6 / 2.6 |
| Energy Loss / turn |
U0 (MeV) |
- / - |
2.15 / 2.50 |
| Total Cavity Voltage |
Vc (MV) |
- / - |
8.4 / 6.7 |
| Energy Spread |
σ δ |
- / - |
8.1 (8.0)x10-4 / 6.49 (6.34)x10-4 |
| Tune |
ν x / ν y |
0.506 / 0.545 |
0.530 / 0.570 |
| Synchrotron Tune |
ν s |
- / - |
-0.0178 / -0.0117 |
| Momentum Compaction |
α p |
- / - |
2.74x10-4 / 1.88x10-4 |
| No. of bunch |
N |
5000 |
2503 |
| Crossing angle |
φ (mrad) |
0 |
83 |
| Beam-beam parameter |
ξ y |
0.30 / 0.51 |
0.09 / 0.088 |
| Luminoisty |
L (cm-2s-1) |
5.35 × 1035 |
8.0 × 1035 |