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

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Super-B Factory Scenarios

John SeemanAssistant DirectorPPA Directorate

SLAC

SLUO MeetingSeptember 11, 2006

Super-B Contributors (Accelerator):

LNF: Biagini, Raimondi, ZobovPisa: Giorgi, PaoloniBINP: Koop, Levichev, ShatilovKEKB: OhmiSLAC: Novokhatski, Roodman, Seeman,

Seryi, Sullivan, WienandsCaltech: AlbertAlso: PEP-II and KEKB staff

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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

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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”

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K. Oide

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0.79 ?

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To be tested in 2007

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K. Ohmi Sept 2006

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K. Oide

Horizontal tune even closer to the half integer (0.503)

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K. OideJuly 2006

12IPFF FF

ILC “like” rings & ILC “like” Final FocusP. Raimondi

Super-B Factory

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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

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Possible site: Tor Vergata near Frascati and Rome

• Near INFN Frascati

• Near future subway

• 3 km rings possible

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K. OideJuly 2006

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IP layout

35cm

35cm

35cm

35cm

2*=30mradL*=35cm

QD0a

QF1_HER

QD0b

LER beam

HER beam

=9mrad

=28mrad

QD0a and QD0b have the same KsQD0a is shared, all theother quads are on the beams trajectories

QF1_LER

70cm

40cm

August 2006Raimondi

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Collisions with crossing angle = 2*25mradand long thin bunches with a small vertical beta.

Horizontal Plane Vertical Plane

Raimondi

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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

Crabbed waist removes bb betratron couplingIntroduced by the crossing angle

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FFTB-style Final Focus

IP phasesextupoles

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HER cell

LER cell

Extra 1.2m bends

Use PEP-II quads and dipoles

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

August 2006

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

September 2006

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Ring Parameters

Energy (GeV) 4 7

C (m) 2762 2762

Bw (T) 1.4 1.05

Lbend(m) 2.1 10.8

N. bends 96 96

Bbend (T) 0.439 0.144

Uo (MeV/turn) 2.3 4.1

Wiggler sections 4 4

z (mm) 7.0 7.0

s (ms) 17 17

x (nm) 0.79 0.71

Emittance ratio 0.25% 0.25%

E 1.0x10-3 1.1x10-3

Momentum compaction 1.85x10-4 3.90x10-4

s 0.012 0.026

Vrf (MV) 5.5 19

Npart (x1010) 3.31 1.89

Ibeam (A) 2.5 1.44

Tousheck lifetime (min) 95 1100

Pbeam(MW) 5.7 5.9

Frf (MHz) 476

Nbunches 4167

Gap 5%

Pwall (MW) (50% eff) 2 rings 23.2

x 20mm

x 4m

xp 200rad

y 200m

y 20nm

yp 100rad

z 7mm

2* 30mrad

IP Parameters

August 2006

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0

5 1036

1 1037

1,5 1037

2 1037

2,5 1037

0 2,5 1010 5 1010 7,5 1010 1 1011 1,25 1011 1,5 1011

Luminosity [cm-2 s-1]

N

Luminosity vs current

Zobov and Shatilov

Nominal

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0,5

1

1,5

2

2,5

3

3,5

0 3 1010 6 1010 9 1010 1,2 1011 1,5 1011

N

Vertical Emittance Blow Up

Gaussian Fit

rms

Beam size blowups vs current

Zobov and Shatilov

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Luminosity Tune Scan (0.8/, z = 7 mm; 3x1010 particles)

Lmax = 2.2x1036 cm-2 s-1

New Qx=0.57 Qy=0.60

29Ax = (0.0:20x) Ay = (0.0:40y)

Luminosity and size blowups vs 2*

New 2* =30mrad, y=133m

Larger crossing angle

Ax

Ay

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Ring dynamic aperture with FFTB-FF

dp/p=0 dp/p=-0.5% dp/p=0.5%

40x 20x 20x

20y 12y 12y

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Recent Super-B Parameters Optimization

• Relaxed damping time => 17msec• Relaxed y/x IP s => 200m/20mm• Relaxed y/x IP s => 20nm/4m• Relaxed crossing angle => 2*15mrad• Relaxed bunch length => 7mm

• L dependence quadratic with current up to 1037

• L of 2 x 1036 is “possible” for 25 to 30 MW.

• PEP-II magnets and 476 MHz RF system reused.• Wiggler sections added to shorten damping time.

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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.