super-b accelerator r&d
DESCRIPTION
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. Super Factories. Linear colliders. - PowerPoint PPT PresentationTRANSCRIPT
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Super-B Accelerator R&D
J. SeemanWith contributions from the Super-B Staff
September 17, 2009
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Outline
• Overview• Super-B parameters• Frascati DAFNE crab waist results• Interaction region• Lattice• Polarization• PEP-II reusable components• Conclusions
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1027
1029
1031
1033
1035
0.1 1 10 100 10001027
1029
1031
1033
1035
Lu
min
os
ity
(c
m-2 s
-1)
c.m. Energy (GeV)
ADONE
DCI
ADONE
VEPP-2M
VEPP2000
DANE
BEPC
SPEAR2
VEPP-4M PETRAPETRA
PEPDORIS2
BEPCII CESR
PEP-II
KEKB
LEP
LEP
LEP
LEP
ILC
CLIC
SUPERKEKB
SuperB
BINP c-
CESR -c
B-Factories-FactoriesFuture Colliders
Linear collidersSuperFactories
Factories
e+e- Colliders
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• 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 Project
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Super-B Accelerator Contributors (~Fall 2009)
• 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)
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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
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How to get 100 times more
y Vertical beam-beam parameter
Ib Bunch current (A) n Number of bunches y
* IP vertical beta (cm) E Beam energy (GeV)
Present day B-factories
PEP-II KEKBE(GeV) 9x3.1 8x3.5Ib 1x1.6 0.75x1n 1700 1600I (A) 1.7x2.7 1.2x1.6y* (cm) 1.1 0.6 y 0.08 0.11L (x1034) 1.2 2.0
*341017.2
y
byEInL
Luminosity equation
Answer:Increase Ib
Decrease y*Increase y
Increase n
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Crab Waist Scheme (Raimondi)
•
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Beam distributions at the 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
With Crab-sextupoles
WithoutCrab-sextupoles
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Crossing Angle Test at DAFNE
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Lum
inos
ity [
1028
cm
-2 s
-1]
y=9mm, Pw_angle=1.9
y=25mm, Pw_angle=0.3
Data averaged for a full day
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Super-B Parameter Options
•
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SuperB Site Choices
Frascati National LaboratoriesExisting Infrastructure
C ~1.4 km
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SPARXSPARX
Collider Hall
Collider Hall
SuperB LINAC
SuperB LINAC
Roman Villa
Roman Villa
SuperB footprint at Tor Vergata Storage rings length = 1800 m
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Perspective view
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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 can be used, dimensions and fields are in range RF requirements are met by the present PEP-II RF system
Lmag
(m) 0.25 0.5
PEP HER/LER 188 -
SBF Total 372 4
Needed 184 4
Sexts
Layout: PEP-II magnets reuse
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•
PEP-II Magnets and RF Components
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Arc Lattice• Arc cell: flexible solution is based on decreasing the natural emittance by increasing
x/cell, and simultaneously adding weak dipoles in the cell drift spaces to decrease synchrotron radiation
• All cells have: x=0.75, y=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
Raimondi, Biagini, Wittmer, Wienands
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•
W. Wittmer
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Lattice Layout (Two Rings) (Sept 2009)
•
Y. Nosochkov
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0 0.2 0.4 0.6 0.8 1
0
0.2
0.4
0.6
0.8
1
0 0.2 0.4 0.6 0.8 1
0
0.2
0.4
0.6
0.8
1
Typical case (KEKB, DANE):
1. low Piwinski angle < 1
2. y comparable with z
Crab Waist On:
1. large Piwinski angle >> 1
2. y comparable with x/
Much higher luminosity!D.Shatilov’s (BINP), ICFA08 Workshop
x-y resonance suppression
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Comparison of design and achieved beam emittances (*achieved)
E (GeV) C (m) x (nm) x (m) y (pm) y(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).
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•
Polarization versus Energy of HER (Wienands)
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RF Plan: Use PEP-II RF system and cavities
•
(Novokhatski, Bertsche)
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PEP-II RF Cavities match Super-B needs.
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Super-B RF Parameters (Sept 2009)
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1) dipole α and …. on-off @ 50 Hz
2) dipole β and …. DC dipoles
4) dipoles and ….. Pulsed inverted dipoles @ 50 Hz
SHB L - 0.8 GeV 5.7 GeV 0.1GeV 0.8 GeV
e+ DR
A B DC
> 7 GeV e+
PS
GUN
≈ 70 m. ≈ 320 m.≈ 60 m.
≈ 400 m.
βθ
e- DR
α R
Injector Layout
R. Boni
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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
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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
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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)
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SC Quadrupoles at the IP (E. Paoloni, S. Bettoni)
•
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Inside the detector
0 1 2 3-1-2-3
0
100
200
-100
-200
mm
meters
QF1
QD0 QD0
QF1
solenoidssolenoids
old support tube BaBar forward door
HER LER
M. Sullivan Feb.13, 2009 SB_IT_ILC_P4_SR_3M
PM QD0
300 mrad
200 mrad
M. Sullivan
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HER LER
0 1 2 3-1-2-3
0
100
-100
-200
mm
metersM. Sullivan Feb.13, 2009 SB_IT_ILC_P4_SR_3M
2.5e6
15680
2.9e7
5.7e5
9.9e6
6.9e5
Photons/beam bunch
HER LER
M. Sullivan
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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
•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
•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
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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.