July 24, 2008Super-B Mini-MAC MeetingPage 1 Super-B Overview John Seeman Accelerator Systems Division SLAC

July 24, 2008 Super-B Mini-MAC Meeting Page 1

Super-B Overview

John Seeman

Accelerator Systems Division

SLAC


Super-B Outline

* Goals for the accelerator* Super-B layout* Super-B parameters* Luminosity options* Subsystems


* 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.

Super-B Goals


Super-B Accelerator Contributors

* 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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(M. Biagini)

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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.


SuperB footprint on Tor Vergata site

SuperB Ring (about 1800m)SPARX

Roman Villa

100m

SuperB Injector (about 400m)

SuperB Main

Building


What about SPAR-X FEL?

*


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)


* 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

Basic concepts

A lot of fine tuning!


SuperB ParametersSuperB Parameters

(Biagini)

Add to these parametershead room factors:X 2 in beam currentX 2 in number of bunchesInjection rate for higher lossesIP beta ranges


Super-B transparency condition

* 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 * and equal currents

E

E

N

N

E

E

y

y

Option 1 for Super-B Option 2 for SuperB

xxyy E

E

E

E ,


Comparison of Super-B to SuperKEKB

Parameter Super-B Super-

KEKB

Energy GeV 4x7 3.5x8

Luminosity 1036

/cm2/s

1.0 0.4

Beam

Currents

Amps 1.9x1.9 10.0x4.0

y* mm 0.22/0.39 3.0

x* 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 vs Super-KEKB

*


Super-B Parameter Flexibility (All with 1036)(LER/HER)

* Option Unit June

2008

CDR Emit y

X 2 higher

Emit y

X 4

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

y* 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

y 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

z mm 6/6 6/6 6/6 6/6 6/6 6/6 12/12 3/3 6/6


(M. Sullivan)

SuperB Interaction Region

0

10

20

30

-10

-20

-300 2.5 5 7.5-2.5-5-7.5

cm

m

QD0 QD0

QD0H

QD0HB00L

B00H

QF1 QF1

B0LB0H

B0L

B0H

QF1QF1

LERHER

M. SullivanNov. 11, 2006SB_IT_ILC_G3


Crab Waist (Raimondi)

*


Beams distribution at 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


Crab-waist Studies at DAFNE at INFN Frascati

* 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– Lowery

– 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.


DAFNE Crab Waist Tests

*


Lattice

* 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

* 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


LER HER

Cell #2

Cell #1 Cell #1

Cell #2

Arc cells layoutM. Biagini


Interaction Region Similar to ILC IR

*


Lattice layout, PEP-II magnets reuse

Total length 1800 m

280 m

20 m

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 are reused. Dimensions and fields are

properly sized.

Lmag

(m) 0.25 0.5

PEP HER/LER 188 -

SBF Total 372 4

Needed 184 4

Sexts


PEP-II RF Cavities

Early design and testing at LBL.

High power production cells.

Fully fitted cavity units with HOM dampers.


*

B-Factory RF Klystrons (1.2 MW)


Super-B RF Parameters

*

Novokhatski


Injection

* Needed rate:1.85 A = 3E13 particlesLifetime = 15 minuteInjector = 5E9 at 100 Hz.

R. Boni


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


HER spin manipulation hardware

Spin rotators in the HER Full HER lattice

Wittmer, Wienands, Biagini


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 e-– Vibration analysis.


*


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Documents

July 24, 2008Super-B Mini-MAC MeetingPage 1 Super-B Overview John Seeman Accelerator Systems Division SLAC