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

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

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

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

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)

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.

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 1.2 1034 1.7 1034 1 1036

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

HER Ring Lattice

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

HER radiative bhabhas

(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

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

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

All and just the Pep RF system fits the SuperB needs

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

DAFNE UPGRADE L => 2.2 x 1033 cm-2 s-1 Horizontal beta @ IP 0.2 m (1.7 m) Vertical beta @ 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

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

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

Crossing Region layout cont. New beam line IP QF1s QD0s

S. Tomassini et all.

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

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

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

tilted and separately powered dipoles bellows crab sextupoles compensator

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

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

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

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

LHC Upgrade

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