1. Update on B and Phi Factories
P. Raimondi
for the SuperB Team
LNF, May 24, 2007

2. Outline Basic Concepts Present Machine Parameters
Status of the SuperB design
Status of the Dafne Upgrade
Conclusions

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
Emitx (sigmax)
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

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

9. HER Ring Lattice

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

11. HER radiative bhabhas

12. (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

13. 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

14. 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

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

16. 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

18. DAFNE UPGRADE L => 2.2 x 1033 cm-2 s-1 Horizontal beta @ IP
0.2 m (1.7 m)
Vertical IP
0.65 cm (1.7 cm)
Horizontal tune
5.057
Vertical tune
5.097
Horizontal emittance
0.2 mm.mrad (0.3)
Coupling
0.5%
Bunch length
20 mm
Total beam current
2 A
Number of bunches
110
Total crossing angle
50 mrad (25 mrad)
Horizontal beam-beam tune shift
0.011
Vertical beam-beam tune shift
0.080
L => 2.2 x 1033 cm-2 s-1

19. Tunes Luminosity Scan Crab On --> 0.6/q Crab Off
Lmax = 2.97x1033 cm-2s-1
Lmin = 2.52x1032 cm-2s-1
Lmax = 1.74x1033 cm-2s-1
Lmin = 2.78x1031 cm-2s-1

20. New Crossing Regions Layout
remove splitters (on both interaction regions)
new vacuum chambers for IP regions
adjust dipole fields and position (Blong lower, Bshort higher - splitters power supplies)
new permanent magnets in the IP1 region
readjust all the other elements (quads, sexts etc)
new components construction (kickers, bellows, diagnostics, etc)
new vacuum system for IP regions

21. Crossing Region layout cont.
New beam line IP
QF1s
QD0s

22. S. Tomassini et all.

23. Aluminum made (very cheap) Thin window thickness= 0.3 mm
Mechanical and Vacuum test done
Construction in progress
mode1
mode2
mode3
mode4
F.Marcellini and D. Alesini
150 W
permanent SmCo quads

24. new compensator position, will not installed in SIDDHARTA setup
new pumping system needed to replace previous slitter pumping system power
new bellows

25. New Shielded bellows HFSS simulation
Axial working stroke = ±5 mm
Radial offset = ±3 mm
HFSS simulation
Beam excited fields in the bellows structure
No significant fields in the volume beyond the shield
F.Marcellini, G. Sensolini

26. tilted and separately powered dipoles
bellows
crab sextupoles
compensator

27. “half moon” chamber
complete beam separation
shape to fit inside existing quads

28. IP2 Y is completely symmetric to IP1 except for crab waist sextupoles and compensator

29. present pulse length ~150ns
New Injection Kickers
New injection kickers with 5.4 ns pulse length have been designed to reduce the perturbation on the stored beam during injection VT VT
50 bunches
3 bunches t t
present pulse length ~150ns
(old kickers)
FWHM pulse length ~5.4 ns
Expected benefits:
higher maximum stored currents
Improved stability of colliding beams during injection
less background allowing acquisition on during injection
F. Marcellini, D. Alesini, G. Sensolini , S. Pella

30. Luminosity monitor for SIDDAHRTA run
TILE CALORIMETER
g MONITOR
PbWO4 crystal
GEM RING

31. LHC Upgrade

32. Conclusions SuperB-Factory very attractive for a national HEP facility
Dafne Upgrade attractive for:
- accelerator phyisics
- possible new runs for
Kloe ( L > 5e32 request)
Finuda ( L > 2e32 request)
Amadeus
If Dafne Upgrade is successful ( L > 5e32), the SuperB acquires a high confidence level