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Super-B Overview. John Seeman Accelerator Systems Division SLAC. Super-B Outline. Goals for the accelerator Super-B layout Super-B parameters Luminosity options Subsystems. Super-B Goals. - PowerPoint PPT Presentation
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July 24, 2008 Super-B Mini-MAC Meeting Page 1
Super-B Overview
John Seeman
Accelerator Systems Division
SLAC
July 24, 2008 Super-B Mini-MAC Meeting Page 2
Super-B Outline
* Goals for the accelerator* Super-B layout* Super-B parameters* Luminosity options* Subsystems
July 24, 2008 Super-B Mini-MAC Meeting Page 3
* Super-B aims at the construction of a very high luminosity (1 x 1036 cm-2 s−1) asymmetric e+e− flavor factory, with possible location at the campus of the University of Rome Tor Vergata, near the INFN Frascati National Laboratory.
* Aims:– Very high luminosity
• Desire 1036: experimenters say 1035 will not get to the physics soon enough.
– High reliability • The goal is integrated luminosity!
– Polarized e- at IP • This is a relatively new addition by the users.
– Ability to collide at Y4S and lower energy (~J/Psi)• For maximum number of experimenters.
Super-B Goals
July 24, 2008 Super-B Mini-MAC Meeting Page 4
Super-B Accelerator Contributors
* D. Alesini, M. E. Biagini, R. Boni, M. Boscolo, T. Demma, A. Drago, S. Guiducci, M. Preger, P. Raimondi, S. Tomassini, C. Vaccarezza, M. Zobov (INFN/LNF, Italy)
* K. Bertsche, Y. Cai, A. Fisher, S. Heifets, A. Novokhatski, M.T. Pivi, J. Seeman, M. Sullivan, U. Wienands, W. Wittmer (SLAC, US)
* T. Agoh, K. Ohmi, Y. Ohnishi (KEK, Japan)* I. Koop, S. Nikitin, E. Levichev, P. Piminov, D. Shatilov (BINP,
Russia) * A. Wolski (Liverpool University, UK)* M. Venturini (LBNL, US)* S. Bettoni, D. Schulte (CERN, Switzerland)* A. Variola (LAL/Orsay, France)* E. Paoloni, G. Marchiori (Pisa University, Italy)
July 24, 2008 Super-B Mini-MAC Meeting Page 52005 2006 2007 2008
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The Super-B Process
Month
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(M. Biagini)
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July 24, 2008 Super-B Mini-MAC Meeting Page 6
Super-B CDR Spring 2007
Initial Super-B design with the ILC damping ring parameters. These parameters are still valid.
However, the parameters have evolved since the CDR to minimize power, shorten the tunnel, and and add polarization.
July 24, 2008 Super-B Mini-MAC Meeting Page 7
SuperB footprint on Tor Vergata site
SuperB Ring (about 1800m)SPARX
Roman Villa
100m
SuperB Injector (about 400m)
SuperB Main
Building
July 24, 2008 Super-B Mini-MAC Meeting Page 8
What about SPAR-X FEL?
*
July 24, 2008 Super-B Mini-MAC Meeting Page 9
Super-B builds on the Successes of Past Accelerators
* PEP-II LER stored beam current (3.2 A in 1722 bunches (4 nsec) at 3.1 GeV at 23 nm with little ECI effect on luminosity.
* Low emittance lattices designed for ILC damping rings, PETRA-3, NSLC-II, and PEP-X. (few nm horizontal x few pm vertical)
* Very low emittance achieved in an ILC test ring: ATF.* Successful crab-waist luminosity improvement at DAFNE in
Frascati.* Successful crab-cavity tests at KEKB at low currents.* Spin manipulation tests in Novosibirsk.* Efficient spin generation with a high current gun and spin transport
to the final focus at the SLC.* Successful two beam interaction region built by KEKB and PEP-II.* Continuous injection works with the detector taking data (KEKB and
PEP-II)
July 24, 2008 Super-B Mini-MAC Meeting Page 10
* Two options:
* High currents– Very high currents– Smaller damping time High power components– Shorter bunches Costly to operate– Crab cavities for head-on collision– Higher power
* SuperB exploits an alternative approach, with a new IP scheme:– Small emittance beams (ILC-DR like)– Large Piwinski angle and “crab waist” – Currents comparable or smaller than present Factories
Basic concepts
A lot of fine tuning!
July 24, 2008 Super-B Mini-MAC Meeting Page 11
SuperB ParametersSuperB Parameters
(Biagini)
Add to these parametershead room factors:X 2 in beam currentX 2 in number of bunchesInjection rate for higher lossesIP beta ranges
July 24, 2008 Super-B Mini-MAC Meeting Page 12
Super-B transparency condition
* To have equal tune shifts with asymmetric energies in PEP-II and KEKB the “design” beam currents ratio is:
I+/I- ~ E-/E+
* Due to SuperB large crossing angle, new conditions are possible: LER and HER beams can have different emittances and * and equal currents
E
E
N
N
E
E
y
y
Option 1 for Super-B Option 2 for SuperB
xxyy E
E
E
E ,
July 24, 2008 Super-B Mini-MAC Meeting Page 13
Comparison of Super-B to SuperKEKB
Parameter Super-B Super-
KEKB
Energy GeV 4x7 3.5x8
Luminosity 1036
/cm2/s
1.0 0.4
Beam
Currents
Amps 1.9x1.9 10.0x4.0
y* mm 0.22/0.39 3.0
x* cm 3.5x2.0 20.
Crossing
angle (full)
mrad 48 30
RF power
(AC line)
MW 17 ~85
Tune shifts (x/y) 0.004/0.15 0.24/0.40
July 24, 2008 Super-B Mini-MAC Meeting Page 14
Super-B vs Super-KEKB
*
July 24, 2008 Super-B Mini-MAC Meeting Page 15
Super-B Parameter Flexibility (All with 1036)(LER/HER)
* Option Unit June
2008
CDR Emit y
X 2 higher
Emit y
X 4
higher
Emity+betay
higher
Betay higher
Bunch
length
longer
Bunch
Length
shorter
Y tune
Shift
0.085
I+/I- Amp 1.85 /1.85
2.28 /1.30
2.28
/1.30
2.28
/1.30
4.56
/2.60
3.42
/1.95
2.28
/1.30
2.28
/1.30
4.56
/2.60
N 1E10 5.52 /5.52
6.16 /3.52
8.71
/4.98
12.4
/7.0
6.16
/3.52
5.0
/2.87
12.4
/7.0
3.1
/1.26
6.16
/3.52
n Num bun 1250 1250 884 625 2500 2296 625 2500 2500
y* mm 0.22 /0.39
0.3 /0.3
0.3
/0.3
0.3
/0.3
0.6
/0.6
0.45
/0.45
0.3/0.3 0.3/0.3 0.3/0.3
y pm 7/4 4/4 8/8 16/16 8/8 4/4 4/4 4/4 16/16
y nm 39/39 35/35 49/49 70/70 70/70 42/42 35/35 35/35 70/70
y Tune shift
0.15/ 0.15
0.17
/0.17
0.17
/0.17
0.17
/0.17
0.17
/0.17
0.17
/0.17
0.17
/0.17
0.17
/0.17
0.085
/0.085
z mm 6/6 6/6 6/6 6/6 6/6 6/6 12/12 3/3 6/6
July 24, 2008 Super-B Mini-MAC Meeting Page 16
(M. Sullivan)
SuperB Interaction Region
0
10
20
30
-10
-20
-300 2.5 5 7.5-2.5-5-7.5
cm
m
QD0 QD0
QD0H
QD0HB00L
B00H
QF1 QF1
B0LB0H
B0L
B0H
QF1QF1
LERHER
M. SullivanNov. 11, 2006SB_IT_ILC_G3
July 24, 2008 Super-B Mini-MAC Meeting Page 17
Crab Waist (Raimondi)
*
July 24, 2008 Super-B Mini-MAC Meeting Page 18
Beams distribution at IP
Crab sextupoles OFF
Crab sextupoles ON
waist line is orthogonal to the axis of one bunch
waist moves to the axis of other beam
All particles from both beams collide in the minimum y region, with a net luminosity gain
E. Paoloni
July 24, 2008 Super-B Mini-MAC Meeting Page 19
Crab-waist Studies at DAFNE at INFN Frascati
* P. Raimondi et al: DAFNE upgrade with improved interaction region to focus tighter the beams at IP and have a “large” crossing angle large Piwinski angle
* Features: – Smaller collision area– Lowery
– No parasitic crossings– No synchro-betatron resonances due to the crossing angle– “Crab Waist” sextupoles
* Results successful and very encouraging so far with improved tunes shifts and higher luminosity with smaller currents.
July 24, 2008 Super-B Mini-MAC Meeting Page 20
DAFNE Crab Waist Tests
*
July 24, 2008 Super-B Mini-MAC Meeting Page 21
Lattice
* The SuperB lattice as described in the Conceptual Design Report is the result of an international collaboration between experts from BINP, Cockcroft Institute, INFN, KEKB, LAL/Orsay, SLAC
* Simulations were performed in many labs and with different codes:
– LNF, BINP, KEK, LAL, CERN
* Further studies after the CDR * completion led to an evolution of * the lattice to fit the Tor Vergata Site * and to include polarization * manipulation hardware.
M. Biagini
July 24, 2008 Super-B Mini-MAC Meeting Page 22
LER HER
Cell #2
Cell #1 Cell #1
Cell #2
Arc cells layoutM. Biagini
July 24, 2008 Super-B Mini-MAC Meeting Page 23
Interaction Region Similar to ILC IR
*
July 24, 2008 Super-B Mini-MAC Meeting Page 24
Lattice layout, PEP-II magnets reuse
Total length 1800 m
280 m
20 m
Lmag
(m) 0.45 5.4
PEP HER - 194
PEP LER 194 -
SBF HER - 130
SBF LER 224 18
SBF Total 224 148
Needed 30 0
Dipoles
Lmag (m) 0.56 0.73 0.43 0.7 0.4
PEP HER 202 82 - - -
PEP LER - - 353 - -
SBF HER 165 108 - 2 2
SBF LER 88 108 165 2 2
SBF Total 253 216 165 4 4
Needed 51* 134 0 4 4
Quads
Available
Needed
All PEP-II magnets are reused. Dimensions and fields are
properly sized.
Lmag
(m) 0.25 0.5
PEP HER/LER 188 -
SBF Total 372 4
Needed 184 4
Sexts
July 24, 2008 Super-B Mini-MAC Meeting Page 25
PEP-II RF Cavities
Early design and testing at LBL.
High power production cells.
Fully fitted cavity units with HOM dampers.
July 24, 2008 Super-B Mini-MAC Meeting Page 26
*
B-Factory RF Klystrons (1.2 MW)
July 24, 2008 Super-B Mini-MAC Meeting Page 27
Super-B RF Parameters
*
Novokhatski
July 24, 2008 Super-B Mini-MAC Meeting Page 28
Injection
* Needed rate:1.85 A = 3E13 particlesLifetime = 15 minuteInjector = 5E9 at 100 Hz.
R. Boni
July 24, 2008 Super-B Mini-MAC Meeting Page 29
Polarization
* Polarization of one beam is included in SuperB– Either energy beam could be the polarized one– The LER would be less expensive, the HER easier– HER was chosen.
* Longitudinal polarization times and short beam lifetimes indicate a need to inject vertically polarized electrons.
– The plan is to use a polarized e- source similar to the SLAC SLC source.
* There are several possible IP spin rotators:– Solenoids look better at present (vertical bends give unwanted vertical emittance
growth)
* Expected longitudinal polarization at the IP of about 87%(inj) x 97%(ring)=85%(effective)
* Polarization section implementation in lattice: in progress with initial success
U. Wienands
July 24, 2008 Super-B Mini-MAC Meeting Page 30
HER spin manipulation hardware
Spin rotators in the HER Full HER lattice
Wittmer, Wienands, Biagini
July 24, 2008 Super-B Mini-MAC Meeting Page 31
Conclusions
* The SuperB design meets the goals requested by the experimenters.
* IR polarization rotators have now been added to the lattice.* The next phase for the accelerator group is to form a team to work
on a Technical Design Report including engineering.* A Change Control Board for parameters is likely needed.* The areas for further concentration:
– Low emittance generation, tuning, dynamic aperture– Crab waist issues– IR design (low betas)– Beam-beam interaction (layout)– Continuous injection with polarization and tolerances– Further beam dynamics studies with ECI for e+ and ions for e-– Vibration analysis.
July 24, 2008 Super-B Mini-MAC Meeting Page 32
*
July 24, 2008 Super-B Mini-MAC Meeting Page 33
*