Transcript Title

Super-B Overview
John Seeman
Accelerator Systems Division
SLAC
July 24, 2008
Super-B Mini-MAC Meeting
Page 1
Super-B Outline
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Goals for the accelerator
Super-B layout
Super-B parameters
Luminosity options
Subsystems
July 24, 2008
Super-B Mini-MAC Meeting
Page 2
Super-B Goals
* 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.
July 24, 2008
Super-B Mini-MAC Meeting
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Super-B Accelerator Contributors
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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)
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Super-B Mini-MAC Meeting
Page 4
The Super-B Process
4 9 11
2005
3 4 6 9 11 12 3 5 5 7 7 9 11 12 1 2
July 24, 2006
2008
Super-B2007
Mini-MAC Meeting
(M. Biagini)
3 4 4 6 6 Month
..
Page
5
2008
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 6
SuperB footprint on Tor Vergata site
SPARX
SuperB Ring
(about 1800m)
SuperB Injector
(about 400m)
Roman Villa
100m
SuperB
Main
Building
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Super-B Mini-MAC Meeting
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What about SPAR-X FEL?
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Super-B Mini-MAC Meeting
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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
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Basic concepts
* 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
A lot of fine tuning!
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Super-B Mini-MAC Meeting
Page 10
SuperB Parameters
Add to these parameters
head room factors:
X 2 in beam current
X 2 in number of bunches
Injection rate for higher losses
IP beta ranges
(Biagini)
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Super-B Mini-MAC Meeting
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Super-B transparency condition
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*
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
b* and equal currents



b
E
y


     
by E

N
E
     
N
E


Option 1 for Super-B
July 24, 2008


E
E
 y    y ,  x    x
E
E

Option 2 for SuperB
Super-B Mini-MAC Meeting
Page 12
Comparison of Super-B to SuperKEKB
Parameter
July 24, 2008
Super-B
SuperKEKB
Energy
GeV
4x7
3.5x8
Luminosity
1036
/cm2/s
1.0
0.4
Beam
Currents
Amps
1.9x1.9
10.0x4.0
by*
mm
0.22/0.39
3.0
bx*
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
Super-B Mini-MAC Meeting
Page 13
Super-B vs Super-KEKB
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Super-B Mini-MAC Meeting
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Super-B Parameter Flexibility (All with 1036)(LER/HER)
Option
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Unit
June
2008
CDR
Emit y
X2
higher
Emit y
X4
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
by*
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
sy
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
sz
mm
6/6
6/6
6/6
6/6
6/6
6/6
12/12
3/3
6/6
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Super-B Mini-MAC Meeting
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(M. Sullivan)
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Crab Waist (Raimondi)
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Super-B Mini-MAC Meeting
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Beams distribution at IP
Crab sextupoles
OFF
E. Paoloni
waist line is orthogonal
to the axis of one bunch
Crab sextupoles
ON
waist moves to the
axis of other beam
All particles from both beams collide in the minimum by region,
with a net luminosity gain
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Super-B Mini-MAC Meeting
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Crab-waist Studies at DAFNE at INFN Frascati
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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
Lower b*y
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 19
DAFNE Crab Waist Tests
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Super-B Mini-MAC Meeting
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Lattice
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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
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*
*
*
*
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 21
Arc cells layout
Cell #1
Cell #1
HER
LER
Cell #2
Cell #2
July 24, 2008
M. Biagini
Super-B Mini-MAC Meeting
Page 22
Interaction Region Similar to ILC IR
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Lattice layout, PEP-II magnets reuse
Total length 1800 m
Lmag (m)
0.45
5.4
PEP HER
-
194
PEP LER
194
-
Available
SBF HER
-
130
Needed
SBF LER
224
18
SBF Total
224
148
Needed
30
0
Dipoles
Quads
280
m
Lmag (m)
0.25
0.5
PEP HER/LER
188
-
SBF Total
372
4
Needed
184
4
Sexts
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
All PEP-II magnets are reused. Dimensions and fields are properly sized.
July 24, 2008
Super-B Mini-MAC Meeting
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PEP-II RF Cavities
Early design and testing at LBL.
High power production cells.
Fully fitted cavity units with
HOM dampers.
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Super-B Mini-MAC Meeting
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B-Factory RF Klystrons (1.2 MW)
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Super-B Mini-MAC Meeting
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Super-B RF Parameters
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Novokhatski
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Super-B Mini-MAC Meeting
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Injection
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Needed rate:
1.85 A = 3E13 particles
Lifetime = 15 minute
Injector = 5E9 at 100 Hz.
R. Boni
July 24, 2008
Super-B Mini-MAC Meeting
Page 28
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 29
HER spin manipulation hardware
Spin rotators in the HER
Full HER lattice
Wittmer, Wienands, Biagini
July 24, 2008
Super-B Mini-MAC Meeting
Page 30
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 eVibration analysis.
July 24, 2008
Super-B Mini-MAC Meeting
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