1. SuperB IRC Meeting Frascati, Nov. 13th 2007
SuperB Overview
P. Raimondi
for the SuperB Team
SuperB IRC Meeting
Frascati, Nov. 13th 2007

2. Basic concepts Increase of plug power ($$$$$..) and hard to operate
B-Factories (PEP-II and KEKB) reach already very high luminosity (~1034 s-1 cm-2 ). To increase of ~ two orders of magnitude (ex. SuperKeKB) it is possible to extrapolate the requirements from the current machines:
Parameters :
Higher currents
Smaller damping time (f(exp1/3))
Shorter bunches
Crab collision
Higher Disruption
Higher power
SuperKeKB Proposal is based
on these concepts
Increase of plug power ($$$$$..) and hard to operate
(high current, short bunches)
look for alternatives keeping constant the luminosity
=> new IP scheme: Small beams, ILC-like
Large Piwinsky Angle and CRAB WAIST

3. Crossing angle concepts
All colliders do need short bunches
to decrease the hourglass effect and
the beams disruption
Overlapping
region Sx
Both cases have the same luminosity,
(2) has longer bunch and smaller sx Sz
With large crossing angle X and Z
quantities are swapped: Very important!!!
1) Standard
short bunches
Overlapping
region Sz Sx
2) Crossing angle

4. High luminosity requires:
- short bunches
- small vertical emittance
- large horizontal size and emittance to mimimize beam-beam
For a ring:
easy to achieve small horizontal emittance and horizontal size
Vertical emittance goes down with the horizontal
Hard to make short bunches
Crossing angle swaps X with Z, so the high luminosity requirements are naturally met:
Luminosity goes with 1/ex and is weakly dependent by sz

5. Vertical waist has to be a function of x:bY e- e+
2Sx/q q
2Sz*q z
2Sz
2Sx
Crab waist removes bb betratron coupling
Introduced by the crossing angle
Vertical waist has to be a function of x:
Z=0 for particles at –sx (- sx/2q at low current)
Z= sx/q for particles at + sx (sx/2q at low current)
Crab waist realized with 2 sextupoles in phase with the IP in X and at p/2 in Y

6. Crab Waist Advantages F = tg(q)sz/sx by sx/q y = xy’/(2q)
Geometric luminosity gain
Very low horizontal tune shift
Large Piwinski’s angle
F = tg(q)sz/sx
2. Vertical beta comparable
with overlap area
by sx/q
3. Crabbed waist transformation
y = xy’/(2q)
Geometric luminosity gain
Lower vertical tune shift
Vertical tune shift decreases with oscillation amplitude
Suppression of vertical synchro-betatron resonances
Geometric luminosity gain
Suppression of X-Y betatron and synchro-betatron resonances

7. eyout/eyin=1.0015 Collisions with uncompressed beams
Horizontal Plane
Vertical Plane
Collisions with uncompressed beams
Crossing angle = 2*25mrad
Relative Emittance growth per collision about 1.5*10-3
eyout/eyin=1.0015

8. KEKB Beams distributions SuperB Beams distributions
Beams are focused in the vertical plane 100 times more than in the present factories, thanks to:
- small emittances
- small beta functions
- large crossing angle
- Crab waist
Tune shifts and longitudinal overlap greatly reduced
KEKB Beams distributions
at the IP
KEKB
SuperB
current
1.7 A
2. A
betay
6 mm
0.3 mm
betax
300 mm
20 mm
sigmax
~80mm
~6mm
sigma y
~3mm
0,039mm
Sigma z L
1 1036
SuperB Beams distributions
at the IP

9. Parameters Optimization: Transparency condition
Due to the large crossing angle, new conditions, instead of unbalanced currents, for having equal tune shifts with asymmetric energies are possible
LER and HER beams can have different emittances and b* and equal currents 

10. e+ sees a shorter interaction region,
(4/7 of the e- one)
e+ has a smaller by*,
natural to acheive in the FF
e+ has larger emittance, 2.8nm
better for the lower energy beam,
less toushek, better tolerance for
instabilities e- e+
LER sz
HER sz

11. Beam-beam blow up weak-strong simulations
HER
Crab=0.8Geom_Crab
LER
Crab=0.9Geom_Crab
1/e Density Contour lines
L=1036 cm-2 s-1
D. Shatilov

12. Beam lifetimes increased, injection rates reduced
Beam Beam simulations shows very good results, no blow up is seen for HER, 1-3% for LER, but some more optimization is possible: tunes, crabbing etc
L=10^36 is predicted
Upgrade parameters can be implemented in any order:
- decrease the emittances first or
- increase the bunch charge or
- increase the number of bunches or
- decrease the bunch length
Less RF Voltage is needed

13. SuperB Parameters (Nov. 2007)
(In red the CDR values)

14. Possible site in the Tor Vergata University close to the Frascati Lab
M. Sullivan

15. SuperB Luminosity Tune Scan (crab=0.8/q, sz = 7 mm; 3x1010 particles)
Lmax = 2.2x1036 cm-2 s-1

16. Luminosity Tune Scan 1 IP 2 IPs Qy Qy Qx Qx Lmin = 3.95 x 1034 cm-2s-1
Lmax = 1.02 x 1036 cm-2s-1
Lmin = 3.37 x 1034 cm-2s-1
Lmax = 1.00 x 1036 cm-2s-1
M.Zobov, D.Shatilov

17. The small emittance rings can be built by using all the PEP-II magnets, starting from the ILC DR design
The rings have circumference flexibility
The FF design complies all the requirements in term of high order aberrations correction, needs to be slightly modified for LER to take care of energy asymmetry
All PEP-II magnets are used, dimensions and fields are in range
RF requirements are met by the present PEP-II RF system

18. SuperB MagnetsShopping list
Dipoles Summary
Available
Lmag (m)
0.45
5.4
PEP HER -
194
PEP LER
SBF HER
130
SBF LER
224 18
SBF Total
148
Needed 30
130 (112 in Arcs+18 in FF) “PEP-II HER” dipoles are used in SuperB HER
18 “PEP-II HER” dipoles are used in FF for SuperB LER
224 “PEP-II LER” dipoles are used in SuperB LER  need to build 30 new ones
SuperB MagnetsShopping list

19. Quadrupoles Summary Lmag (m) 0.56 0.73 0.43 0.7 0.4 PEP HER 202 82 -
Available
Lmag (m)
0.56
0.73
0.43
0.7
0.4
PEP HER
202 82 -
PEP LER
353
SBF HER
165
108 2
SBF LER 88
SBF Total
253
216 4
Needed
51*
134
* Spare 0.43 m long quadrupoles can be used (23)

20. All and just the Pep RF system
fits the SuperB needs

21. Dafne Run with Crab Waist
Machine upgrade almost completed
Cold checkouts will start ‘round Nov.20
Commissioning should last until Dec.20
Physics run will begin in January until june-15 (goal Lint=1fb-1)
Luminosity goal is >5e32 (present record is 1.6e32) with crab sextupoles and >2e32 without

22. Conclusions
SuperB studies are already proving useful to the accelerators and particle physics community
We have a preliminary “Conceptual Design Report”, based on the reuse of all the Pep hardware, that might fit in one of the existing facilities, or in a new (and avalaible) site near Frascati
We hope to gather in the enterprise as many labs and institutions as possible (see the CDR for the ones already involved)

23. LHC Upgrade
Possible fall back on the existing factories
The crab waist seems to be beneficial also for the current factories
Potential to simultaneously boost the performances of the existing machines and do SuperB R&D