1. SuperB CDR Machine
P. Raimondi
for the SuperB Team
Paris, May 9, 2007

2. Outline Basic Concepts Present Machine Parameters
Status of the SuperB design
Where when and how to build the SuperB
To do list

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

4. Crossing angle concepts
Overlapping
region
Both cases have the same luminosity,
(2) has longer bunch and smaller sx Sx
With large crossing angle X and Z
quantities are swapped: Very important!!! Sz
1) Standard
short bunches
Overlapping
region Sz Sx
2) Crossing angle

5. 1). Large Piwinski angle - high sz and collision angle
1) Large Piwinski angle - high sz and collision angle. (Slight L decrease)
allows point (2) & decrease the disruption due to the effective z overlap & minimise parasitic collision. Long bunches are good for the ring stability (CSR, HOM…) but
Introduces B-B and S-B resonances (strong coordinates coupling).
2) Extremely short b*y (300 mm) - so little s*y (20 nm - High L gain…)
3) Large angle scheme already allows to suppress SB resonances
4) Small horizontal emittance (Horizonatal tune compensated by large Piwinski angle)

6. bY ….and (finally) to crab the waist:x
….and (finally) to crab the waist: bY e- e+
2Sx/q q
2Sz*q z
2Sz
2Sx
Why? Crabbed waist removes betratron coupling resonances
introduced by the crossing angle (betatron phase and amplitude
modulation)
Vertical waist has to be a function of x:
Crabbed waist realized with a sextupole in phase with the IP in X and at p/2 in Y
…….and slight increase of the luminosity.

7. But where is the real gain?
PEPII
KEKB
SuperB
current
2.5 A
1.7 A
2.3 A
betay
10 mm
6 mm
0.3 mm
betax
400 mm
300 mm
20 mm
Emity (sigmay)
23 nm (~100mm)
~ the same (~80mm)
1,6 nm
(~6mm)
y/x coupling
(sigma y)
0,5-1 %
0.1 %
(~3mm)
0,25 %
(0,035mm)
Bunch length
Tau l/t
16/32 msec
~ the same zy
0.07
0.1
0.16 L
1 1036

9. FFTB-stile Final FocusSd Sd Sf Sf
FFTB-stile Final Focus Sd Sf
IP phase
sexts
Ring+FF Bandwidth

10. SuperB: sb70_ff_linepro12
Y. Ohnishi IP

11. HER radiative bhabhas

12. HER Ring Lattice

13. Dynamic aperture of ideal lattice with final focus and octupoles
Including higher-order terms (beyond the paraxial approximation) in the quadrupoles:

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

15. We have proven the feasibility of small emittance rings using all the PEP-II magnets, modifying 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

16. SuperB Magnets Shopping list
Dipoles Summary
Lmag (m)
0.45
5.4 2
0.75
PEP HER -
192 8
PEP LER
SBF HER
160
SBF LER
144 16
SBF Total
176 4
Needed
160 (144 in Arcs+16 in FF) “PEP-II HER” dipoles are used in SuperB HER
16 dipoles are used in FF for SuperB LER
144 “PEP-II LER” dipoles are used in SuperB LER  need to build 144 new ones, 0.75 m long
SuperB Magnets Shopping list
We have excess of:
48 bends 0.45 m long
16 bends 5.4 m long
4 bends 2. m long

17. Quadrupoles Summary We have excess of: 38 quads 1. m long Lmag (m)
0.56
0.73
0.5
0.43
0.75
0.4
0.45
1.0
PEP HER 94 82 - 70 22
PEP LER
282 16
SBF HER
248
138 36 2
SBF LER 44
302
SBF Total
292 72 4
Needed
198 56 20
We need 354 quads:
198 quads 0.56 m long
56 quads 0.73 m long
20 quads 0.43 m long
72 quads 0.5 m long
4 quads 0.75 m long
4 quads 0.4 m long
We have excess of:
38 quads 1. m long

18. Sextupoles Summary Lmag (m) 0.25 0.6 PEP HER 144 - PEP LER 8 SBF HER
216 12 4
SBF LER
SBF Total
432 24
Needed 16
High gradient !
We need 168 sexts:
144 sexts 0.25 m long
16 sexts 0.25 m long with high gradient
8 quads 0.6 m long

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

20. Wall Plug Power
around 30 MWatt

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

22. Possible fall back on the existing factories
The crabbed 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

24. Novosibirsk is designing a tau-charm factory based On The Crab-Waist
Large piwinski angle and
Crab Waist will be used
in the Dafne run next fall
to try to improve the luminosity
by a factor > 3
QD0
QF1s

25. M. Zobov With the present achieved beam parameters
Present achieved currents
L=1.5e32
With the present achieved beam parameters
(currents, emittances, bunchlenghts etc) a luminosity in
excess of 1033 is predicted.
With 2Amps/2Amps more than 2*1033 is possible
Beam-Beam limit is way above the reachable currents

26. A lot of studies to understand the effects of the crab sextupoles done
Working progress
A lot of studies to understand the effects of the crab sextupoles done
A preliminary solution now exists
(Ohnishi talk)
Very long to do list to for the ring design optimization:
Include the injection section, the tunes trombone and the chicane in the ring
Optimize the ARC cell
Optimize the wigglers
Improve the Dynamic Aperture (Mostly FF and Crab Waist Optics optimization)
Design the Injection System