1 Super-B Factory Scenarios John Seeman Assistant Director PPA Directorate SLAC SLUO Meeting September 11, 2006

Super-B Contributors (Accelerator): LNF: Biagini, Raimondi, Zobov Pisa: Giorgi, Paoloni BINP: Koop, Levichev, Shatilov KEKB:Ohmi SLAC: Novokhatski, Roodman, Seeman, Seryi, Sullivan, Wienands Caltech:Albert Also: PEP-II and KEKB staff

3 Super-B Workshops Frascati: November 2005 Daresbury: April 2006 SLAC: June 2006 KEK: September 13-15, 2006 SLAC: October 19-24, 2006 Frascati: November 13-15, 2006

4 Outline There are two present avenues of study for a future very high luminosity B-Factory: –Super KEKB (extension of present machines) Use existing KEK tunnel, magnets, RF system, New injector, vacuum system, crab cavities, IR High current and high AC power –“Damping ring style” collider “Super-B” (new concept): New lattice similar to ILC damping ring New IR similar to ILC final focus Crab-waist for low vertical beta but long bunches Present currents and low AC power Reuse “PEP-II RF and magnets”

5 K. Oide

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7 To be tested in 2007

8 K. Ohmi Sept 2006

9 K. Oide Horizontal tune even closer to the half integer (0.503)

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11 K. Oide July 2006

12 IP FF ILC “like” rings & ILC “like” Final Focus P. Raimondi Super-B Factory

13 Super-B Factory Design Design still fresh and changing Started with ILC parameters but has evolved toward smaller rings as new features were added: –Full lattices developed –IR developed with good beam-stay-clear –New IR included in lattice studies –4 GeV x 7 GeV –Dynamic apertures are good –Tune plane is good. –Fewer bunches are needed, so shorter rings than ILC

14 Possible site: Tor Vergata near Frascati and Rome Near INFN Frascati Near future subway 3 km rings possible

15 K. Oide July 2006

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17 IP layout 35cm 2*  =30mrad L*=35cm QD0a QF1_HER QD0b LER beam HER beam  =9mrad  =28mrad QD0a and QD0b have the same Ks QD0a is shared, all the other quads are on the beams trajectories QF1_LER 70cm 40cm August 2006 Raimondi

18 Collisions with crossing angle = 2*25mrad and long thin bunches with a small vertical beta. Horizontal PlaneVertical Plane Raimondi

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20 Vertical waist has to be a function of x: Z=0 for particles at –  x (-  x /2  at low current) Z=  x /  for particles at +  x (  x /2  at low current) Crabbed waist realized with a sextupole in phase with the IP in X and at  /2 in Y 2Sz 2Sx  z x 2Sx/  2Sz*  e- e+ YY Crabbed waist removes bb betratron coupling Introduced by the crossing angle

21 FFTB-style Final Focus IP phase sextupoles

22 HER cell LER cell Extra 1.2m bends Use PEP-II quads and dipoles

23 HER ring lattice with FF (Option A: 2.7 km) August 2006

24 HER ring lattice with FF (Option B: 1.7 km) September 2006

25 Ring Parameters Energy (GeV)47 C (m)2762 B w (T) L bend (m) N. bends96 B bend (T) Uo (MeV/turn) Wiggler sections44  z (mm) 7.0  s (ms) 17  x (nm) Emittance ratio0.25% EE 1.0x x10 -3 Momentum compaction1.85x x10 -4 s Vrf (MV)5.519 N part (x10 10 ) I beam (A) Tousheck lifetime (min) P beam (MW) Frf (MHz)476 N bunches 4167 Gap5% P wall (MW) (50% eff) 2 rings23.2 xx 20mm xx4m4m  xp200  rad yy200  m yy 20nm  yp100  rad zz 7mm 2*  30mrad IP Parameters August 2006

26 Luminosity vs current Zobov and Shatilov Nominal

27 Beam size blowups vs current Zobov and Shatilov

28 Luminosity Tune Scan (0.8/ ,  z = 7 mm; 3x10 10 particles) L max = 2.2x10 36 cm -2 s -1 New Qx=0.57 Qy=0.60

29 A x = (0.0:20  x ) A y = (0.0:40  y ) Luminosity and size blowups vs 2*  New 2*  =30mrad,  y=133  m Larger crossing angle Ax Ay

30 Ring dynamic aperture with FFTB-FF dp/p=0dp/p=-0.5%dp/p=0.5% 40  x 20  x 20  y 12  y

31 Recent Super-B Parameters Optimization Relaxed damping time => 17msec Relaxed y/x IP  s => 200  m/20mm Relaxed y/x IP  s => 20nm/4  m Relaxed crossing angle => 2*15mrad Relaxed bunch length => 7mm L dependence quadratic with current up to L of 2 x is “possible” for 25 to 30 MW. PEP-II magnets and 476 MHz RF system reused. Wiggler sections added to shorten damping time.

32 Conclusions A very high luminosity B-Factory seems to have several possible technical avenues. Recent studies show good progress for an “ILC like” ring and FF solution but of shorter length. The AC power is similar to present B- Factories. The study group aim is to have a “Technical Paper” written by the end 2006.