1. Polarization at the Super-B Factory
J. Seeman
SLAC
IRC Meeting
November 13, 2007

2. Polarization studies for Super-B
Contributions from:
I. Koop (BINP)
S. Nikitin (BINP)
M. Preger (INFN Frascati)
P. Raimondi (INFN Frascati)
J. Seeman (SLAC)
U. Wienands (SLAC)

3. Why not let the beam self-polarize?
Polarization time:
SBF beam lifetime =~ 5 minutes
 Inject polarized electrons from the linac

4. Ring Layout (from F. Forti)
SuperB Ring (about 1800m)
SPARX
SuperB Injector (about 400m)
Roman Villa
100m
SuperB Main Building

5. Polarization Components from the SLC at SLAC
Example of Injected Polarized Electrons
Polarization Components from the SLC at SLAC
Polarized Photo-Gun
120 Hz, 87%
2 x 5x10^10/pulse
Spin manipulators
SLC IP
Located at the Stanford Linear Accelerator Center
Polarization equipment ready for reuse!

6. IP Spin Rotation

7. Spin Transport Issues Spin rotation x-y coupling Spin chromaticity
Depolarizing resonances
IP symmetry
Beam-beam forces

8. “Foot print” shape preferred

10. Alternative #1of IP Spin Rotator

11. Alternative #2 of IP Spin Rotator
Derbenev, Kondratenko, Skrinsky, 1977
Snake rotates spin
by 1800 around z-axis
Snake
In arcs spin lies
in the horizontal plane
At IP the spin is directed
longitudinally (exactly!) IP

13. Polarization times LER: HER:
Best energies: 3.83 GeV, 4.10 GeV to avoid resonances
Polarization times:
10800 sec with antisymmetric IP horiz. bends
3300 sec with symmetrical IP horiz. bends
HER:
Best energies: 6.92 GeV, 7.18 GeV to avoid resonances
Polarization time:
2800 sec with antisymmetric IP horiz. bends

14. Polarization Conclusions
Polarization of one beam is included in Super-B.
Either energy beam could be the polarized one.
The LER would be less expensive.
Long polarization times and short beam lifetimes indicates a need to inject polarized electrons in the vertical plane.
There are several possible IP spin rotators.
Solenoids look better at present.
Expected longitudinal polarization at the IP of about 87%(inj) x 97%(ring)=85%(effective).