Super-B Factory Scenarios

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Super-B Factory Scenarios

• John Seeman
• Assistant Director
• PPA Directorate
• SLAC
• SLUO Meeting
• September 11, 2006

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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
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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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Horizontal tune even closer to the half integer
(0.503)
K. Oide
10

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K. Oide July 2006
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Super-B Factory
ILC like rings ILC like Final Focus
P. Raimondi
FF
FF
IP
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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. Oide July 2006

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IP layout
LER beam
2q30mrad L35cm
QF1_LER
QD0a
70cm
Dq28mrad
35cm
QD0b
Dq9mrad
35cm
35cm
QF1_HER
40cm
QD0a and QD0b have the same Ks QD0a is shared,
all the other quads are on the beams trajectories
HER beam
35cm
Raimondi
August 2006
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Horizontal Plane
Vertical Plane
Collisions with crossing angle 225mrad and
long thin bunches with a small vertical beta.
Raimondi
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x
bY
e-
e
2Sx/q
q
2Szq
z
2Sz
2Sx
Crabbed waist removes bb betratron
coupling Introduced by the crossing angle

• Vertical waist has to be a function of x
• Z0 for particles at sx (- sx/2q at low
  current)
• Z sx/q for particles at sx (sx/2q at low
  current)
• Crabbed waist realized with a sextupole in
  phase with the IP in X and at p/2 in Y

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FFTB-style Final Focus
IP phase sextupoles
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HER cell
Extra 1.2m bends
LER cell
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
sz (mm) 7.0 7.0
ts (ms) 17 17
ex (nm) 0.79 0.71
Emittance ratio 0.25 0.25
sE 1.0x10-3 1.1x10-3
Momentum compaction 1.85x10-4 3.90x10-4
ns 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) 476 476
Nbunches 4167 4167
Gap 5 5
Pwall (MW) (50 eff) 2 rings 23.2 23.2
IP Parameters
bx 20mm
sx 4mm
sxp 200mrad
by 200mm
sy 20nm
syp 100mrad
sz 7mm
2q 30mrad
August 2006
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Luminosity vs current
Nominal
Zobov and Shatilov
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Beam size blowups vs current
Zobov and Shatilov
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Luminosity Tune Scan (0.8/q, sz 7 mm 3x1010
particles)
Lmax 2.2x1036 cm-2 s-1
New Qx0.57 Qy0.60
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Luminosity and size blowups vs 2q
New 2q 30mrad, by133mm
Larger crossing angle
Ay
Ax
Ax (0.020sx) Ay (0.040sy)
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Ring dynamic aperture with FFTB-FF
20sx
40sx
20sx
dp/p0
dp/p-0.5
dp/p0.5
20sy
12sy
12sy
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Recent Super-B Parameters Optimization

• Relaxed damping time gt 17msec
• Relaxed y/x IP bs gt 200mm/20mm
• Relaxed y/x IP ss gt 20nm/4mm
• Relaxed crossing angle gt 215mrad
• Relaxed bunch length gt 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.