Super-B Accelerator R&D

Super-B Accelerator R&D

J. SeemanWith 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

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

• 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

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)

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

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

Crab Waist Scheme (Raimondi)

•

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

Crossing Angle Test at DAFNE

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

Super-B Parameter Options

•

SuperB Site Choices

Frascati National LaboratoriesExisting Infrastructure

C ~1.4 km

SPARXSPARX

Collider Hall

Collider Hall

SuperB LINAC

SuperB LINAC

Roman Villa

Roman Villa

SuperB footprint at Tor Vergata Storage rings length = 1800 m

Perspective view

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

•

PEP-II Magnets and RF Components

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

•

W. Wittmer

Lattice Layout (Two Rings) (Sept 2009)

•

Y. Nosochkov

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

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).

•

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)

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

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

0 1 2 3-1-2-3

0

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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

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

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

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.