First approach to the SuperB Rings

1
First approach to the SuperB Rings

• M. Biagini, LNF-INFN
• April 26th, 2006
• UK SuperB Meeting, Daresbury

2
SuperB Rings

• A new SuperB scheme came out from the 2nd SuperB
  Workshop held in Frascati in March 2006
• A document was written for the CERN Strategy
  Group and INFN Roadmap and can be found at the
  http//www.pi.infn.it/SuperB/
• The rings have same length and beam parameters as
  the ILC Damping Rings
• An attempt to scale the ILCDR lattice to the
  SuperB energies has been done
• Scaling to 3 Km length has also been performed

3
SuperB sketch
Electron ring 4 GeV Positron ring 7 GeV
4
SuperB Rings Parameters
5

• The ILCDR OCS lattice has been used as a baseline
  for the SuperB Damping Rings
• The 2 SuperB rings have asymmetric energies of 4
  and 7 GeV
• Two configuration for 6 Km and 3 Km circumference
  were studied
• Emittances and damping times were kept constant
• Lattice symmetry was respected
• Magnetic elements were kept the same, with fewer
  wigglers

6
ILCDR Parameters
7
OCS ILC
FODO cell
135/90 FODO cells 10 wiggler cells, 1.6 T
Wiggler cell
8
ILCDR Scaling

• OCS lattice, 6.1 Km ILC Damping Rings, 10 wiggler
  sections
• 4 GeV same wiggler sections and field, same bend
  length
• 7 GeV same wiggler field, double bend length,
  less wiggler sections (6)
• No Final Focus yet

9
4 GeV OCS ring, 6 Km
FODO cell
135/90 FODO cells 10 wiggler cells, 1.6 T
Wiggler cell
10
7 GeV OCS ring, 6 Km
Double length bends
FODO cell
135/90 FODO cells 8 wiggler cells, 1.6 T
Wiggler cell
11
6 Km rings
DR 5 GeV SBF 4 GeV SBF 7 GeV
C (m) 6113.92 6113.92 6113.92
Bw (T) 1.6 1.6 1.6
Lbend(m) 5.6 5.6 11.2
Bbend (T) 0.1 0.078 0.136
Uo (MeV/turn) 9.33 5.66 10.68
tx (ms) 22 28.8 26.
ts (ms) 11 14.4 13
ex (nm) 0.56 0.57 0.57
Frf (MHz) 650 650 650
12
3 Km Rings

• The OCS lattice has many free drifts and a
  relatively low number of quadrupoles and bends ?
  quite easy to shorten the ring
• Quadrupole strengths and beta peaks are higher
  though
• No optimization performed yet, but possible

13
SBF 4 GeV SBF 7 GeV
C (m) 3006. 3006.
Bw (T) 1.6 1.6
Lbend(m) 5.6 11.2
Bbend (T) 0.078 0.136
Uo (MeV/turn) 4.6 7.8
N. wigg. cells 8 4
tx (ms) 17.5 18.
ts (ms) 8.8 9.
ex (nm) 0.54 0.54
sE 1.1x10-3 1.45x10-3
Ibeam (A) 2.5 1.4
Pbeam(MW) 11.5 10.9
cm sE0.9x10-3
Total Wall Power (66 transfer eff.) 34 MW
14
4 GeV, 3Km
15
7 GeV, 3Km
16
Quadrupole gradients comparison
Gradients for SB4 and SB7 were not optimized yet.
Can still be lowered by changing drifts in cells
17
Possible issues of 3 Km ring

• Same as ILCDR, that is
• Find good dynamic aperture
• HER e-cloud instability ? curved electrodes
• LER Intra Beam Scattering
• Fast Ion Instability ? gaps in train

18
Curved clearing electrodes
M. Pivi L. Wang T. Raubenheimer - P.
Raimondi, SLAC
19
Curved clearing electrodes
Near the bunch core no e-cloud !
using POSINST
M. Pivi P. Raimondi, SLAC, Mar 2006
20
Intra Beam Scattering
OCS lattice, 5 GeV
DR Baseline Configuration Document, Feb. 06
21
Conclusions

• 2 ring lattices for asymmetric energies have been
  studied by simply scaling the ILCDR OCS lattice
• Both 6 and 3 km lattices look feasible, is seems
  also possible to further scale down the length
• A lot of work still needed
• Insertion of Final Focus
• Dynamic aperture study
• Collective effects study
• Beam instabilities will be different due to
  different energies and need to be studied
  especially for the LER
• Full synergy with ILCDR