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

B-Factories  -Factories Future Colliders Linear colliders Super Factories e+e- Colliders

Super-B aims at the construction of a very high luminosity (1x 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 (~10 36 ) –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  I b Bunch current (A)  n Number of bunches  y * IP vertical beta (cm)  E Beam energy (GeV) Present day B-factories PEP-IIKEKB E(GeV) 9x3.18x3.5 I b 1x x1 n I (A) 1.7x x1.6  y * (cm)  y L (x10 34 ) Luminosity equation Answer: Increase I b 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 Without Crab-sextupoles

Crossing Angle Test at DAFNE

Luminosity [10 28 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 Laboratories Existing Infrastructure C ~1.4 km

SPARX Collider Hall SuperB LINAC Roman Villa SuperB footprint at Tor Vergata Storage rings length = 1800 m

Perspective view

L mag (m) PEP HER-194 PEP LER194- SBF HER-130 SBF LER22418 SBF Total Needed300 Dipoles L mag (m) PEP HER PEP LER SBF HER SBF LER SBF Total Needed51* 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 L mag (m) PEP HER/LER188- SBF Total3724 Needed1844 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

Typical case (KEKB, DA  NE): 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 ILC-DR Diamond* ATF* SLS* SuperB LER SuperB HER 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  …. 50 Hz 2) dipole β and  …. DC dipoles 4) dipoles  and  ….. Pulsed inverted 50 Hz SHB L 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. β θ 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 M. Sullivan

2.5e e7 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.