Update on B and Phi Factories P Raimondi

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

Outline • • • Basic Concepts Present Machine Parameters Status of the Super. B design Status of the Dafne Upgrade Conclusions

Basic concepts • B-factories reachs already very high luminosity (~10 34 s-1 cm-2 ). To increase of ~ two orders of magnitude (Ke. KB-Super. Ke. KB) it is possible to extrapolate the requirements from the current machines: Parameters : • Higher currents • Smaller damping time (f(exp 1/3)) • Shorter bunches • Crab collision • Higher Disruption • Higher power • Super. Ke. KB 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 Sz With large crossing angle X and Z quantities are swapped: Very important!!! 1) Standard short bunches Overlapping region Sz 2) Crossing angle Sx

1) Large Piwinski angle - high sz and collision angle. (Slight L decrease) Þ 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)

x …. and (finally) to crab the waist: e+ b. Y e- 2 Sx/q q 2 Sz*q z 2 Sx 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 Super. B 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 (~100 mm) ~ the same (~80 mm) 1, 6 nm (~6 mm) y/x coupling (sigma y) 0, 5 -1 % (~6 mm) 0. 1 % (~3 mm) 0, 25 % (0, 035 mm) Bunch length 10 mm 6 mm Tau l/t 16/32 msec ~ the same 16/32 msec zy 0. 07 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

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

HER radiative bhabhas

Luminosity Tune Scan (crab=0. 8/q, sz = 7 mm; 3 x 1010 particles) Lmax = 2. 2 x 1036 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

Dipoles Summary Lmag (m) 0. 45 5. 4 2 0. 75 PEP HER - 192 8 - PEP LER 192 - - - SBF HER - 160 2 - SBF LER 144 16 2 144 SBF Total 144 176 4 144 Needed 0 0 0 • 160 (144 in Arcs+16 in FF) “PEP-II HER” dipoles are used in Super. B HER • 16 dipoles are used in FF for Super. B LER • 144 “PEP-II LER” dipoles are used in Super. B LER need to build 144 new ones, 0. 75 m long 144 Super. B 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 Super. B 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 Super. B R&D

DAFNE UPGRADE Horizontal beta @ IP Vertical beta @ IP 0. 2 m (1. 7 m) 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. 97 x 1033 cm-2 s-1 Lmax = 1. 74 x 1033 cm-2 s-1 Lmin = 2. 52 x 1032 cm-2 s-1 Lmin = 2. 78 x 1031 cm-2 s-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 IP 1 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 QF 1 s QD 0 s

S. Tomassini et all.

• Aluminum made (very cheap) • Thin window thickness= 0. 3 mm • Mechanical and Vacuum test done • Construction in progress 150 W F. Marcellini and D. Alesini permanent Sm. Co quads mode 1 mode 2 mode 3 mode 4

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 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

IP 2 Y is completely symmetric to IP 1 except for crab waist sextupoles and compensator

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 3 bunches 50 bunches present pulse length ~150 ns (old kickers) t FWHM pulse length ~5. 4 ns t 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 Pb. WO 4 crystal GEM RING

LHC Upgrade

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