Transcript Super-B Accelerator R&D J. Seeman With contributions from the Super-B Staff September 17, 2009

Super-B Accelerator R&D
J. Seeman
With contributions from the Super-B Staff
September 17, 2009
Outline
•
•
•
•
•
•
•
•
Overview
Super-B parameters
Frascati DAFNE crab waist results
Interaction region
Lattice
Polarization
PEP-II reusable components
Conclusions
e+e- Colliders
Super
Factories BINP c-
35
10
SuperB
SUPERKEKB
Linear colliders10
35
ILC
KEKB
CLIC
Factories
33
10
BEPCII
-2
-1
Luminosity (cm s )
PEP-II
CESR
DANE
10
LEP
BEPC
VEPP-2M
10
31
10
29
10
27
LEP
CESR -c DORIS2
VEPP2000
33
LEP
PEP
31
10
LEP
PETRA
PETRA
VEPP-4M
SPEAR2
ADONE
29
10
B-Factories
-Factories
Future Colliders
DCI
ADONE
27
10
0.1
1
10
100
c.m. Energy (GeV)
1000
Super-B Project
• Super-B aims at the construction of a very high
luminosity (1x 1036 cm-2 s−1) asymmetric e+e−
flavor factory with a possible location on or near
the campuses of the University of Rome at Tor
Vergata or the INFN Frascati National Lab.
• Aims:
–
–
–
–
–
Very high luminosity (~1036)
Flexible parameter choices.
High reliability.
Longitudinally polarized beam (e-) at the IP (>80%).
Ability to collide at the Charm threshold.
Super-B Accelerator Contributors (~Fall 2009)
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•
•
•
•
•
•
•
D. Alesini, M. E. Biagini, R. Boni, M. Boscolo, A. Clozza, T. Demma, A.
Drago, M. Esposito, A. Gallo, S. Guiducci, V. Lollo, G. Mazzitelli, C.
Milardi, L. Pellegrino, M. Preger, P. Raimondi, R. Ricci, C. Sanelli, G.
Sensolini, M. Serio, F. Sgamma, A. Stecchi, A. Stella, S. Tomassini, C.
Vaccarezza, M. Zobov (INFN/LNF, Italy)
K. Bertsche, A. Brachmann, Y. Cai, A. Chao, A. DeLira, M. Donald, A.
Fisher, D. Kharakh, A. Krasnykh, N. Li, D. MacFarlane, Y. Nosochkov, A.
Novokhatski, M. Pivi, J. Seeman, M. Sullivan, U. Wienands, J. Weisend,
W. Wittmer, G. Yocky (SLAC, US)
A. Bogomiagkov, S.Karnaev, I. Koop, E. Levichev, S. Nikitin, I. Nikolaev, I.
Okunev, P. Piminov, S. Siniatkin, D. Shatilov, V. Smaluk, P. Vobly (BINP,
Russia)
G. Bassi, A. Wolski (Cockroft Institute, UK)
S. Bettoni (CERN, Switzerland)
M. Baylac, J. Bonis, R. Chehab, J. DeConto, Gpmez, A. Jaremie, G.
Lemeur, B. Mercier, F. Poirier, C. Prevost, C. Rimbault, Tourres, F. Touze,
A. Variola (CNRS, France)
A. Chance, O. Napoly (CEA Saclay, France)
F. Bosi, E. Paoloni (Pisa University, Italy)
A New Idea
• Pantaleo Raimondi came up with a new scheme to attain
high luminosity in a storage ring
– Change the collision so that only a small fraction of one bunch
collides with the other bunch
• Large crossing angle
• Long bunch length
– Due to the large crossing angle the effective bunch length (the
colliding part) is now very short so we can lower y* by a factor of
50
– The beams must have very low emittance – like present day light
sources
• The x size at the IP now sets the effective bunch length
– In addition, by crabbing the magnetic waist of the colliding
beams we greatly reduce the tune plane resonances enabling
greater tune shifts and better tune plane flexibility
• This increases the luminosity performance by another factor of 2-3
How to get 100 times more
Luminosity equation
L  2.1710
34
xy
Ib
n
y*
E
nx y EIb
Vertical beam-beam
parameter
Bunch current (A)
Number of bunches
IP vertical beta (cm)
Beam energy (GeV)

*
y
Present day B-factories
PEP-II
E(GeV) 9x3.1
Ib
1x1.6
n
1700
I (A)
1.7x2.7
y* (cm) 1.1
xy
0.08
L (x1034)
1.2
Answer:
Increase
Decrease
Increase
Increase
KEKB
8x3.5
0.75x1
1600
1.2x1.6
0.6
0.11
2.0
Ib
y*
xy
n
Crab Waist Scheme (Raimondi)
•
Beam distributions at the IP
Crab sextupoles
OFF
Without
waist line is orthogonal
Crab-sextupoles
to the axis of one bunch
Crab sextupoles
ON
With
Crab-sextupoles
waist moves to the
Paoloni
axis ofE.other
beam
All particles from both beams collide in the minimum y region,
with a net luminosity gain
Crossing Angle Test at DAFNE
Data averaged for a full day
Luminosity [1028 cm-2 s-1]
y=9mm, Pw_angle=1.9
y=25mm, Pw_angle=0.3
Super-B Parameter Options
•
SuperB Site Choices
C ~1.4 km
Frascati National Laboratories
Existing Infrastructure
Collider
Hall
Roman
Villa
SuperB
LINAC
SPARX
SuperB footprint at Tor Vergata
Storage rings length = 1800 m
Perspective view
Layout: PEP-II magnets reuse
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
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 can be used, dimensions and fields are in range
RF requirements are met by the present PEP-II RF system
PEP-II Magnets and RF Components
•
Arc Lattice
Raimondi, Biagini, Wittmer, Wienands
•
•
•
•
•
Arc cell: flexible solution is based on decreasing the natural emittance by increasing
mx/cell, and simultaneously adding weak dipoles in the cell drift spaces to decrease
synchrotron radiation
All cells have: mx=0.75, my=0.25  about 30% fewer sextupoles
Better DA since all sextupoles are at –I in both planes (although x and y sextupoles
are nested)
Distances between magnets compatible with PEP-II hardware
All quads-bends-sextupoles in PEP-II range
Arcs & FF
W. Wittmer
•
Lattice Layout (Two Rings) (Sept 2009)
•
Y. Nosochkov
x-y resonance suppression
D.Shatilov’s (BINP), ICFA08 Workshop
Much higher luminosity!
1
1
0.8
0.8
0.6
0.6
0.4
0.4
0.2
0.2
0
0
0
0.2
0.4
0.6
0.8
Typical case (KEKB, DANE):
1
0
0.2
0.4
0.6
0.8
Crab Waist On:
1. low Piwinski angle  < 1
1. large Piwinski angle  >> 1
2. y comparable with sz
2. y comparable with sx/q
1
Comparison of design and achieved beam emittances (*achieved)
E (GeV)
C (m)
g
ex (nm)
gex (mm)
ey (pm)
gey(nm)
Spring-8
8
1430
15656
6
94
5
78
ILC-DR
5
6400
9785
1
10
2
20
Diamond*
3
561
5871
2.7
16
2
29
ATF*
1.28
138
2524
1
2.5
4
10
SLS*
2.4
288
4700
6
28
3.2
15
SuperB LER
4
1800
7828
2.8
22
7
55
SuperB HER
7
1800
13699
1.6
22
4
55
Emittance tuning techniques and algorithms have been tested in simulations and
experiments on the ATF and on the other electron storage rings to achieve such small
emittances (ex. CesrTA as an ILC-DR test facility has a well established one).
Polarization versus Energy of HER (Wienands)
•
RF Plan: Use PEP-II RF system and cavities
•
(Novokhatski, Bertsche)
PEP-II RF Cavities match Super-B needs.
Super-B RF Parameters (Sept 2009)
Injector Layout
1) dipole α and g….
on-off @ 50 Hz
2) dipole β and q….
DC dipoles
4) dipoles l and d ….. Pulsed inverted dipoles @ 50 Hz
e- DR
A
GUN
SHB
L - 0.8 GeV
R
α
β
g
C
B
5.7 GeV
≈ 70 m.
0.1GeV
≈ 320 m.
PS
D
0.8 GeV
≈ 60 m.
e+ DR
≈ 400 m.
R. Boni
θ
> 7 GeV e+
The IR design
• The interaction region design has to accommodate
the machine needs as well as the detector
requirements
–
–
–
–
Final focus elements as close to the IP as possible
As small a detector beam pipe as backgrounds allow
As thin as possible detector beam pipe
Adequate beam-stay-clear for the machine
• Low emittance beams helps here
– Synchrotron radiation backgrounds under control
– Adequate solid angle acceptance for the detector
Final focus magnets
• Up to now, factories have typically developed
interaction regions with at least one shared
quadrupole
• However, with the large crossing angle of the
SuperB design this means at least one beam is far
off axis in a shared magnet
• This magnet therefore strongly bends the off-axis
beam which produces powerful SR fans and even
emittance growth
• To avoid this, the SuperB design has developed a
twin final focus doublet for both beams
R&D on SC Quadrupoles at the IP
Total field in black
Coils array
Most recent
design with
BSC
envelopes
E. Paoloni (Pisa),
S. Bettoni (CERN)
SC Quadrupoles at the IP (E. Paoloni, S. Bettoni)
•
Inside the detector
M. Sullivan
200
old support tube
solenoids
solenoids
QD0
100
mm
QD0
LER
HER
0
BaBar
forward
door
300 mrad
QF1
QF1
PM
QD0
-100
200 mrad
-200
-3
-2
-1
meters
0
1
2
M. Sullivan
Feb.13, 2009
SB_IT_ILC_P4_SR_3M
3
Photons/beam bunch
HER
M. Sullivan
2.5e6
2.9e7
6.9e5
9.9e6
15680
5.7e5
LER
TDR Topic List
•Injection System
•Polarized gun
•damping rings
•spin manipulators
•linac
•positron converter
•beam transfer systems
•Collider design
•Two rings lattice
•Polarization insertion
•IR design
•beam stay clear
•ultra-low emittance tuning
•detector solenoid compensation
•coupling correction
•orbit correction
•stability
•beam-beam simulations
•beam dynamics and instabilities
•single beam effects
•operation issues
•injection scheme
•RF System
•RF specifications
•RF feedbacks
•Low level RF
•Synchronization and timing
•Site
•Civil construction
•Infrastructures & buildings
•Power plants
•Fluids plants
•Radiation safety
•Magnets
•Design of missing magnets
•Refurbishing existing magnets
•Field measurements
•QD0 construction
•Power supplies
•Injection kickers
•Mechanical layout and alignment
•Injector
•supports
•Vacuum system
•Arcs pipe
•Straights pipe
•IR pipe
•e-cloud remediation electrodes
•bellows
•impedance budget simulations
•pumping system
•Diagnostics
•Beam position monitors
•Luminosity monitor
•Current monitors
•Synchrotron light monitor
•R&D on diagnostics for low emittance
•Feedbacks
•Transverse
•Longitudinal
•Orbit
•Luminosity
•Electronics & software
•Control system
•Architecture
•Design
•Peripherals
Conclusions
• Crossing angle collisions work well experimentally
at DAFNE.
• Parameters for a high luminosity collider seem to
hold together. Both Super-B and Super-KEKB now
have similar parameters.
• Detailed site work and lattice layout computations
are advancing.
• IR design is coming together
• Working on accelerator tolerances now.
• Aiming at a White Paper at end of 2009 and TDR
at end of 2010.