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Status of DA F NE2 project

Status of DA F NE2 project. C. Biscari. 22 th LNF Scientific Committee, Frascati, 29 th November 2005. DA F NE2 team. D. Alesini, G. Benedetti, M. E. Biagini, R. Boni, M. Boscolo, A. Clozza,

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Status of DA F NE2 project

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  1. Status of DAFNE2 project C. Biscari 22th LNF Scientific Committee, Frascati, 29th November 2005

  2. DAFNE2 team D. Alesini, G. Benedetti, M. E. Biagini, R. Boni, M. Boscolo, A. Clozza, G. Delle Monache, G. Di Pirro, A. Drago, L. Falbo, J. Fox++, A. Gallo, A. Ghigo, S. Guiducci, M. Incurvati, E. Levichev+, C. Ligi, F. Marcellini, G. Mazzitelli, C. Milardi, S. Nikitin+, L. Pellegrino, P. Piminov+, M. A. Preger, P. Raimondi, R. Ricci, C. Sanelli, M. Serio, F. Sgamma, D. Shatilov+, B. Spataro, A. Stecchi, A. Stella, D. Teytelman**, C. Vaccarezza, M. Vescovi, M.Zobov, LNF-INFN, Frascati, Italy + BINP, Novosibirsk, Russia ** SLAC, USA

  3. e+ e-colliders in the world VEPP 4M – operation since 2000 VEPP2000 – first beam 2006 CESR-c – shutdown 2007 BEPC – first beam 2006 PEP II – shutdown 2008 KEK B – operation until 2008 SUPER KEKB – to be approved DAFNE – operation until 2008 Upgrade to be approved The only e+ e- collider in Europe

  4. Past - Present Future

  5. DAFNE upgradeEnergy and Luminosity Range K physics Nuclear physics Nucleon form factors Kaonic nuclei Light source PHYSICS case :afternoon session

  6. How much we need to modify DAFNE? IR Vacuum chamber Control system Diagnostics Injection kickers Wigglers Rf system Feedback Injection lines Cryogenic system Dipoles Radiation shielding High energy High luminosity

  7. N+N- Higher luminosities • Increasing of cross section with current due • Beam-beam • Single beam effects • (Single bunch effects + • Total current effects) • Stronger for lower energy Increasing the luminosity by: Increasing the slope (smaller cross section) Increasing the current Fighting the blowup effects

  8. Higher energies Higher Magnetic fields EASIER Increasing the luminosity by: Increasing the slope (smaller cross section) Fighting the blowup effects BUT Power = Current x Energy loss Limit in power = Limit in current

  9. Keep basic DAFNE design: two rings flat beams multibunch high currents Change: Only one Interaction Region flexible for all the different experiments Preferred choice: use of the same detector

  10. Present KLOE IR Coupling compensation: Quadrupole rotation depending on E and/or Bdet Low beta quads : permanent magnet for fixed energy Mechanical rotation for Detector solenoid compensation

  11. IR Tunable design Based on SC technology (Lately developed for colliders (HERA,BEPC) and ILC) Bdet = 0.2 to 0.4 T Br = 1.7 to 4.0 Tm e- dip dip QF + sol + skew QD + sol + skew dip dip dip Antisolenoids and skews compensate coupling in the whole range of energies and Bdet e+ Double steering to adjust crossing angle 2.5 m

  12. DAFNE2 quads Gmax = 28 T/m Brett Parker, Snowmass ILC meeting

  13. IR optical functions E = 0.51 GeV bx* = 1 m by* = 1 cm qcross = 15 mrad E = 1.2 GeV bx* = 1 m by* = 1.5 cm qcross = 15 mrad

  14. Parasitic crossing B- B tune shifts E = 0.51 GeV Bunch spacing 60 cm In the first 2.5 m : 8 pc (every 30 cm) E = 1.2 GeV Bunch spacing 3 m First pc after 1.5 m

  15. Tune scans with BEAM – BEAM simulations in progress to optimize working point and IP parameters

  16. Synchrotron radiation integrals Choice of lattice, dipoles, wigglers Emittance - I2, I4, I5 Damping time - I2 Energy spread - I3, I4 Natural bunch length - I3, I4 Emitted power - I2

  17. Damping time and radiation emission Energy emitted per turn Damping time In DAFNE now: I2 = 9.5 m-1 , Uo = 9 keV, tx = 37 msec I2 = 4.5 dipoles + 5 wigglers

  18. DIPOLES Choice of normal conducting dipoles Maximum field: 1.8 T @1.2 GeV I2 = 2.8 m-1 1.8 T Dipole Magnet, POISSON simulation

  19. Wigglers are needed to increase radiation and make beam stronger against instabilities by decreasing damping time The contribution to I2 by wigglers is : In our case: tx (@510 MeV) = 13 msec : I2 = 26 m-1 Lw = 6.5 @ B = 4 T With same wigglers and scaled dipoles @1.2GeV: tx =5 msec I2 = 6.5 m-1

  20. Dispersion D D D W W I5 Emittance Wigglers in dispersive zones increase I5and emittance depending onb and D functions. Wigglers in non-dispersive zones increase I2 and lower emittance

  21. Wigglers influence beam parameters and dynamics Change the radiation integrals Non-linear effects: affect dynamic aperture, lifetime, beam-beam behavior Wigglers in a non-dispersive zone with low betas for non linear kicks minimisation + One Wiggler in a dispersive region for emittance tuning (as in DAFNE now for Beam-beam tune shift optimisation)

  22. E = 0.51 GeV E = 1.2 GeV B = 4 T B = 4 T Choice of wiggler shape Good field region centered around wiggler axis CESRc design: even # poles Usual wiggler design: odd # poles Trajectory position with respect to wiggler axis, depends on E and B Trajectory centered on wiggler axis, independently of E and B

  23. Choice of pole length, lw Once defined Ltotal and Bmax Radiation, emittance, energy spread are determined Transverse non-linearities: increase with lw Longitudinal non-linearities: decrease with lw

  24. By (s) By (x) DBy/By = 5 10-4 @ 2 cm Collaboration with BINP group: SC Wiggler built at BINP Bmax = 7 T for SIBERIAII

  25. Energy spread – bunch length – rf system Natural bunch length and energy spread at low current are defined by the magnetic lattice, the momentum compaction and the rf system More radiation – larger energy spread – longer bunch Bunch length can be shortened by increasing h, V

  26. Microwave longitudinal instability Above Ith sL increases with the current, not depending on ac Short bunch length at high current: • Low impedance • High ac • High voltage MEASUREMENTS ON DAFNE

  27. Bunch lengthening with current Present operating currents (12 - 16 mA) DAFNE now ZII/n = 1.0 W V=0.2 MV ZII/n = 0.6 W V=0.2 MV • DAFNE2: • ZII/n = 0.6 W • Higher ac • Higher sp/p (extra wigglers) • Higher Voltage (V=1.5 MV) • Ithr = 30 mA @ 0.51 GeV • Ithr > 50 mA @1.2 GeV sz(mm) Nominal design current (16 mA)

  28. Vertical Size Blow Up in DAFNE now sy (mm) • - Single bunch (beam) effect • - Correlated with the • longitudinal microwave • instability: • The same threshold • The same dependence on Vrf • The threshold is higher for higher momentum compaction • More pronounced for e- ring ac = 0.02 ac = 0.034 Bunch length (cm) ac = 0.02 Higher Ithr will fight this effect ac = 0.034

  29. RF system Higher frequencies – lower acceptance Lower frequencies – higher voltage A possible candidate cavity 500 MHz SC cavity operating at KEKB R&D on SC cavities with SRFF experiment in DAFNE

  30. Touschek beam lifetime and natural bunch length as a function of rf voltage (energy acceptance)

  31. High currents NOW: I- = 1.8 AI+ = 1.3 A routinely Maximum stored current: I- = 2.4 AI+ = 1.5 A Maximum e- current Stored in any accelerator Experience in Feedbacks - Well in end Going to 2.5 A – no expected difficulties for e- While e-cloud limiting e+ R&D in progress, simulations, possible cures, possibility of Ti coating DAFNE vacuum chamber

  32. NEXT-GENERATION FEEDBACK Design specifications such to fulfill the ultimate performance specifications of present and new high current multibunch machines First FPGA board prototype tested in DAFNE AS IT IS (SLAC-LBL-INFN COLLABORATION) 1 - Farm of DSP filters 2 - Down-sampled reconstruction of synchrotron oscillation 3 - Front-end and back-end electronics, together with all the fast digital electronics, i.e.: timing, down-sampler and hold buffer, housed in a VXI system. DSP filters implemented in VME boards. VXI and VME sub-systems linked via high-speed serial links. FUTURE (MoU KEK-SLAC signed) 1 - FPGA logic 2 - All samples -> uniform approach for longitudinal and transverse 3 - "ALL-IN-ONE", possibly

  33. August 05

  34. Injection system • Linac + Accumulatore OK • Doubling transfer lines for optimizing <L> • New kickers (R&D in progress) • Ramping for high energy option To be studied the possibility of using on – energy injection for the HE and compatibility with SPARXINO The High Luminosity option needs continuous injection

  35. STUDIES FOR NEW DAFNE INJECTION KICKERS K K K K E=510 Mev # of bunches=120(max) Stored current=1.5-2.0A Schematic of the present injection kicker system and kicker structure 2 kickers for each ring  ~ 10mrad Beam pipe radius = 44 mm Kicker length = 1m VT VT t t aimed FWHM pulse length ~5.4 ns present pulse length ~150ns

  36. Longitudinal rms motion bunch by bunch at injection e+ ring (July 2005) Kicker length Injected bunch: 92

  37. EVALUATION OF THE KICKER LENGTH (L) AND THE PULSE SHAPE (Lf , Lr) (Lf-2L)/c=LB/c Generator pulse shape VIN Deflecting voltage VT 2DB Lf /c t t (2L+Lr)/c (2L+Lr)/c Lr /c Lr /c GENERATOR REQUIREMENTS(Θnorm=0.69mrad.MeV/cm/kV) Lf - 2L=LB=4z inj140mm Lr+Lf=2DB 1.6m Let’s assume: Lr/c=300ps L  680mm Lf/c = 5ns Neglecting the bunch length... L  750mm Lf/c = 5ns Lf - 2L=LB=0

  38. Optical functions at f - energy RF e tuning Damping Wigglers Background minimization injection IP

  39. IR + section for background minimization DIPOLE 180° Phase advance between last dipole and QF in IR . Particles produced in the dipole will pass near the axis in the quadrupole, and wont be lost Scrapers along the ring to stop particles produced elsewhere Beam direction

  40. Optical functions at 1.2 GeV RF Damping Wigglers injection

  41. F. Sgamma

  42. Tentative schedule • To -> TDR and Project approval (2006) • To + 1 year -> call for tender • To + 2 years -> construction and delivery • To + 3 years -> DAFNE decommissioning and DAFNE2 installation • To + 4 years -> 1st beam for commissioning and for 1st experiment (2010) Different experiments must be planned in temporal sequence since they use the same IR

  43. DAFNE - KLOE KEKB - BELLE

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