SuperB and Super KEKB SuperB and Super KEKB The Precision - - PowerPoint PPT Presentation

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SuperB and Super KEKB SuperB and Super KEKB The Precision Frontier Precision Frontier The U. Wienands U. Wienands SLAC, presently at CERN SLAC, presently at CERN Former PEP-II Run Coordinator Former PEP-II Run Coordinator

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SLIDE 1
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

1

SuperB and Super KEKB SuperB and Super KEKB The The “ “Precision Frontier Precision Frontier” ”

  • U. Wienands
  • U. Wienands

SLAC, presently at CERN SLAC, presently at CERN Former PEP-II Run Coordinator Former PEP-II Run Coordinator

I am indebted to M. Iwasaki and to M. Masuzawa, KEK, for providing me with I am indebted to M. Iwasaki and to M. Masuzawa, KEK, for providing me with material on Super KEKB material on Super KEKB

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SLIDE 2
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

2

Outline Outline

  • Introduction

Introduction

  • The Crab Waist

The Crab Waist

  • The SuperB proposals

The SuperB proposals

  • Conclusion

Conclusion

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SLIDE 3
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

3

B B-Factories: Success Story

  • Factories: Success Story
  • PEP-II: 1.2 10

PEP-II: 1.2 1034

34/cm

/cm2

2/s, about 0.5 ab

/s, about 0.5 ab–

–1 1

  • KEKB: 2.1 10

KEKB: 2.1 1034

34/cm

/cm2

2/s, about 1 ab

/s, about 1 ab–

–1 1

  • PEP-II/BaBar together with KEKB-Belle:

PEP-II/BaBar together with KEKB-Belle:

– Definitive measurement of sin(2ß), solid foundation for CKM formalism – Exceeded their physics goals – Proved that multi-ampere beam currents can be handled

  • up to 3.2 A @ 3.1 GeV; 2 A @ 9 GeV in PEP-II

– Proved that background is manageable

  • s.r. background as well as lost-particle background

– Proved that high overall efficiency can be maintained

  • PEP-II/BaBar reached >85% up time
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SLIDE 4
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

4

Super Super B B-Factories

  • Factories
  • A growing momentum has built up to expand on

A growing momentum has built up to expand on the program and push for new reach on the the program and push for new reach on the “ “precision frontier precision frontier” ”

  • This physics reach is possible with 50

This physics reach is possible with 50… …100 ab 100 ab–

–1 1

  • f data
  • f data
  • In order to gather such an amount in a reasonable

In order to gather such an amount in a reasonable time, a peak luminosity of time, a peak luminosity of ≈ ≈10 1036

36 cm

cm–

–2 2s

s–

–1 1 is

is necessary necessary

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SLIDE 5
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

5

e e+

+

e e–

– Luminosity Trend

Luminosity Trend

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SLIDE 6
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

6

Luminosity Equation Luminosity Equation

  • It then follows that, for fixed beam-beam parameter

It then follows that, for fixed beam-beam parameter ξ ξ, one , one needs higher beam current and/or lower needs higher beam current and/or lower ß ßy

y*

*. .

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SLIDE 7
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

7

Strategies Strategies

  • Head-on collisions (

Head-on collisions (R RL

L=1): hourglass becomes important

=1): hourglass becomes important

– σl ≥ 2 mm – > ß* ≥ 2 mm => need O(10) A beam current 

  • Crossing angle (horizontal):

Crossing angle (horizontal):

– foreshortens the IP => ß* ≤ σl is possible – > synchro-betatron coupling due to beam-beam 

  • “

“Crab Waist Crab Waist” ” can reduce or eliminate the effect of crossing angle can reduce or eliminate the effect of crossing angle 

– Raimondi, LNF, based on earlier work by Balakin, BINP – Successfully operated at DAΦNE, Luminosity gain ≈ *2.5.

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SLIDE 8
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

8

High Beam Current/Short Bunches High Beam Current/Short Bunches

  • Problems of high beam current for short bunches:

Problems of high beam current for short bunches:

BPM damage due to overheating Rf seal damage

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SLIDE 9
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

9

Graphics by

  • E. Paoloni

Crab Waist Crab Waist

Raimondi

Tune scan, Tune scan, red red=higher luminosity =higher luminosity

Crab sextupoles: n Crab sextupoles: nπ π in x; in x; (n+1/2) (n+1/2)π π in y from IP in y from IP

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SLIDE 10
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

10

DA DAΦ ΦNE Luminosity NE Luminosity

Crab Waist

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SLIDE 11
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

11

Towards next-Generation Towards next-Generation B B-Factories

  • Factories
  • Both

Both B B-Factory teams have proposed upgrades

  • Factory teams have proposed upgrades

exploiting this scheme: exploiting this scheme:

– Super KEKB: Upgrade of existing KEKB – SuperB: New facility, to be built at LNF in a collaboration of LNF, SLAC, several European Laboratories and BINP Novosibirsk.

  • While the challenges are similar for both facilities,

While the challenges are similar for both facilities, they differ in the details: they differ in the details:

– Super KEKB: ≈3 km circumference (KEKB tunnel), no polarized beam, KEKB hardware – SuperB: 1.25 km circumference, polarized electrons, PEP-II hardware

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SLIDE 12
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

12

Common Features Common Features

  • Energy asymmetry: 4 on 7 GeV

Energy asymmetry: 4 on 7 GeV

  • Crossing angle:

Crossing angle: 2* 41.5 mr, 2*30 mr 2* 41.5 mr, 2*30 mr

  • Small beam emittances (nmr in

Small beam emittances (nmr in x x, pmr in , pmr in y y) )

– Beam aspect ratios ≈ 1/100

  • Beam currents up to

Beam currents up to ≈ ≈ 3.5 A or less 3.5 A or less

  • Bunch length

Bunch length ≈ ≈ 5 mm 5 mm

  • Short beam lifetime (

Short beam lifetime (≈ ≈ 5 min) 5 min)

– continuous injection (“trickle charge”)

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SLIDE 13
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

13

KEKB/SuperKEKB KEKB/SuperKEKB

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SLIDE 14
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

14

KEKB Site KEKB Site

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SLIDE 15
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

15

Super KEKB Parameters Super KEKB Parameters

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SLIDE 16
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

16

Low Emittance Lattice Low Emittance Lattice

  • Achieving low emittance with minimum change

Achieving low emittance with minimum change

– Replace short dipoles with longer ones for LER ≈100 0.89 m dipoles replaced with 4 m ones.

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SLIDE 17
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

17

SuperKEKB Lattice SuperKEKB Lattice

Crab Crab

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SLIDE 18
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

18

Super SuperB B Parameters Parameters

  • Energy:

Energy: 6.78 ( 6.78 (e e+

+) on 4.18 (

) on 4.18 (e e–

–) GeV

) GeV

  • Half crossing angle:

Half crossing angle: 30 mr 30 mr

  • Horiz. emittance:
  • Horiz. emittance:

2 2

  • n
  • n

2.5 nmr 2.5 nmr

  • Vertic. emittance:
  • Vertic. emittance:

5 5

  • n
  • n

6 nmr 6 nmr

  • ß

ßx

x/

/ß ßy

y at IP:

at IP: 26/0.25 on 26/0.25 on 32/0.21 mm 32/0.21 mm

  • Beam currents:

Beam currents: 1.9 1.9

  • n
  • n

2.5 A 2.5 A

  • Beam-beam parameter

Beam-beam parameter ξ ξy

y:

: 0.097 0.097

  • Beam lifetime:

Beam lifetime: 4.2 4.2

  • n
  • n

4.5 min 4.5 min

  • Luminosity:

Luminosity: 1 1× ×10 1036

36 cm

cm–

–2 2s

s–

–1 1

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SLIDE 19
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

19

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SLIDE 20
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

20

Super SuperB B Tunnel Layout Tunnel Layout

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SLIDE 21
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

21

µx = 3π, µy = π Cell in HER µx = 3π, µy = π Cell in LER

Low Emittance Lattice Low Emittance Lattice

  • Lattice near TME

Lattice near TME

– synch.-rad. type design

  • In the LER, dipole

In the LER, dipole position adjusts the position adjusts the emittance emittance

  • ≈

≈ 5 mm bunch 5 mm bunch length length

– acceptable

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SLIDE 22
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

22

V12

Match & SR X-sext Y-sext Crab

LER Interaction Region LER Interaction Region

  • Spin Rotator outside local chromaticity correction

Spin Rotator outside local chromaticity correction

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SLIDE 23
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

23

Chromatic behaviour of the IP Chromatic behaviour of the IP

  • ß

ß chromaticity ( chromaticity (W W) corrected at IP ) corrected at IP

– necessary condition for high momentum bandwidth

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SLIDE 24
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

24

SuperB LER Spin Rotation SuperB LER Spin Rotation

IP HER HER LER LER

S.r. solenoids (90° spin) S.r. dipoles (270° spin)

  • 90° spin rotation about

90° spin rotation about x x axis axis

– 90° about z followed by 270° about y

  • “

“flat flat” ” geometry => no vertical emittance growth geometry => no vertical emittance growth

  • Solenoid scales with energy => LER more economical

Solenoid scales with energy => LER more economical

  • Solenoids are split & decoupling optics added.

Solenoids are split & decoupling optics added.

Compton IP for polarimetry

slide-25
SLIDE 25
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

25

SuperB LER Polarization SuperB LER Polarization

3.5 min beam lifetime

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SLIDE 26
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

26

Polarimetry Polarimetry

  • Compton polarimeter,

Compton polarimeter, γ γ and and e e–

– detection

detection

– bunch-by-bunch, < 1% systematic error

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SLIDE 27
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

27

Super KEKB Final-Focusing system Super KEKB Final-Focusing system

  • Crossing angle 83 mrad to make the FF magnets close to

Crossing angle 83 mrad to make the FF magnets close to IP IP

slide-28
SLIDE 28
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

28

Super KEKB IR Beam Pipe Super KEKB IR Beam Pipe

e+ e-

  • Crotched structures (Two FF Q-magnets in both

Crotched structures (Two FF Q-magnets in both sides) sides)

  • 1cm radius of vtx chamber

1cm radius of vtx chamber

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SLIDE 29
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

29

Detector Background Detector Background

  • SR background

SR background

– not worse than present B-Factories;

  • Lost-particle background

Lost-particle background

– Touschek factor 20-30 higher (SuperKEKB est.) – beam collimation can help (SuperB)

  • Radiative Bhabhas (

Radiative Bhabhas (∝ ∝ Luminosity) Luminosity)

– Shielding (n), optics (e+,e–) to deal with – SuperKEKB Study: can be reduced by factor 40 c.f. KEKB

slide-30
SLIDE 30
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

30

Super KEKB S/C Magnet R&D Super KEKB S/C Magnet R&D

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SLIDE 31
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

31

SuperB IR Layout SuperB IR Layout

100 200

  • 100
  • 200

1 2 3

  • 1
  • 2
  • 3

mm m

3-Oct-09
  • M. Sullivan
SB_I_ILC_R3_SR_3M

QF1 QF1 HER LER PM Solenoids QD0 300 mrad 200 mrad Cryostat PEP-II Support tube

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SLIDE 32
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

32

SuperB IR Quad Designs SuperB IR Quad Designs

Scalloped solenoid magnets Scalloped solenoid magnets 3 coils x 2 (to cancel solenoid) 3 coils x 2 (to cancel solenoid) ⇒ ⇒different fields possible different fields possible

  • E. Paoloni, S. Bettoni
  • E. Paoloni, S. Bettoni

Alternative QD0: Superferric Alternative QD0: Superferric (P. Vobly, BINP) (P. Vobly, BINP)

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SLIDE 33
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

33

Beam-Beam (Ohmi) Beam-Beam (Ohmi)

  • Strong-strong simulation for

Strong-strong simulation for SuperKEKB SuperKEKB

– crab waist increases L from ≤7 to ≤9 1035.

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SLIDE 34
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

34

Beam-Beam (cont Beam-Beam (cont’ ’d) d)

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SLIDE 35
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

35

Misalignments (Luzzio, Super Misalignments (Luzzio, SuperB B) )

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SLIDE 36
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

36

e e-Cloud Simulations (Demma, Super

  • Cloud Simulations (Demma, SuperB

B) )

  • e

e-Cloud was seen in both KEKB and PEP-II

  • Cloud was seen in both KEKB and PEP-II

– details differ somewhat (PEP-II: mostly x, KEKB: mostly y) – successfully mitigated with beam-line solenoids – strongly dependent on bunch pattern, vac. syst. (ante-chamber)

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SLIDE 37
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

37

Super KEKB Vacuum Chamber Super KEKB Vacuum Chamber

Beam channel NEG pump SR channel

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SLIDE 38
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

38

Super KEKB Chamber Prototypes Super KEKB Chamber Prototypes

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SLIDE 39
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

39

SuperKEKB SuperKEKB

  • New Ante-chamber beam pipes

New Ante-chamber beam pipes

– Mitigation techniques for suppression of electron cloud.

  • New IR design
  • New IR design

– New superconducting/permanent magnets around IP. – Optimization of the compensation solenoid. – Local Chromaticity correction sections for both rings.

  • New low emittance optics for both e+e-rings
  • New low emittance optics for both e+e-rings

– Replace dipoles, change wiggler layout for e+ ring

  • New low emittance beam injections
  • New low emittance beam injections

– New damping ring & target for e+ – New RF gun for electrons

  • Higher beam currents
  • Higher beam currents

– Add / modify the RF systems

  • Precise beam diagnostics and tunings
  • Precise beam diagnostics and tunings

– More precise magnet setting ⇔power supplies.

slide-40
SLIDE 40
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

40

SuperKEKB Projection SuperKEKB Projection

Shutdown for upgrade Commissioning starts mid of 2014 9 month/year 20 days/month 50 ab–1 in 2020…2021. Peak Luminosity ∫ Luminosity (ab–1)

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SLIDE 41
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

41

SuperB Projection SuperB Projection

Peak Luminosity (1035 cm–2s–1 ∫ Luminosity (ab–1)

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SLIDE 42
  • U. Wienands, SLAC
  • U. de Paris, 16-Sep-10

42

Conclusion Conclusion

  • Two next-generation

Two next-generation B B-Factories are in an

  • Factories are in an

advanced design stage. advanced design stage.

– Both use a large crossing angle and have provisions for a crab-waist sextupole pair – The crab waist was proposed and successfully operated at DAFNE – SuperB add polarized electrons as an integral component of the design

  • Direct evolution of the extremely successfull

Direct evolution of the extremely successfull B B-

  • Factories (about 1.5 ab

Factories (about 1.5 ab–

–1 1 combined data set).

combined data set).