First approach to the SuperB Rings

M. Biagini, LNF-INFN

April 26th, 2006

UK SuperB Meeting, Daresbury

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

SuperB sketch

e+ DR

e-

IP

FF -FF

Electron ring: 4 GeVPositron ring: 7 GeV

SuperB Rings Parameters

• 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

ILCDR Parameters

OCS

OCS ILC

Wiggler cell

FODO cell

135°/90° FODO cells10 wiggler cells, 1.6 T

• 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

ILCDR Scaling

4 GeV OCS ring, 6 Km

Wiggler cell

FODO cell

135°/90° FODO cells10 wiggler cells, 1.6 T

135°/90° FODO cells8 wiggler cells, 1.6 T

FODO cell

Wiggler cell

Double length bends7 GeV OCS ring, 6 Km

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

x (ms) 22 28.8 26.

s (ms) 11 14.4 13

x (nm) 0.56 0.57 0.57

Frf (MHz) 650 650 650

6 Km rings

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

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

x (ms) 17.5 18.

s (ms) 8.8 9.

x (nm) 0.54 0.54

E 1.1x10-3 1.45x10-3

Ibeam (A) 2.5 1.4

Pbeam(MW) 11.5 10.9Total Wall Power (66% transfer eff.): 34 MW

cm E=0.9x10-3

4 GeV, 3Km

7 GeV, 3Km

Quadrupole gradients comparison

Gradients for SB4 and SB7 were not optimized yet. Can still be lowered by changing drifts in cells

0

0,5

1

1,5

2

2,5

ILCDR & SuperB quadrupole comparison

OCSSB4SB7

Dispersion Suppressorto be optimized

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

M. Pivi – L. Wang – T. Raubenheimer - P. Raimondi, SLAC

Curved clearing electrodesCurved clearing electrodesCurved clearing electrodesCurved clearing electrodes

Curved clearing electrodesCurved clearing electrodesCurved clearing electrodesCurved clearing electrodes

using POSINST

M. Pivi – P. Raimondi, SLAC, Mar 2006

Near the bunch core: no e-cloud !

Intra Beam Scattering

DR Baseline Configuration Document, Feb. 06

x growth

z growth

y growth

E growth

OCS lattice, 5 GeV

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