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Status of DA F NE upgrade project

Status of DA F NE upgrade project. C. Biscari for the DA F NE team. Napoli -19 september 2005. DA F NE today. 16 September. L peak = 1.53 cm -2 sec -1. Integrated luminosity = 9.4 pbarn -1. 430 nbarn -1 /hour -> 10 pbarn -1 per day. KLOE. FINUDA. SRFF ?. SIDDHARTA. TODAY. 2008?.

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Status of DA F NE upgrade project

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  1. Status of DAFNE upgrade project C. Biscari for the DAFNE team Napoli -19 september 2005

  2. DAFNE today 16 September Lpeak = 1.53 cm-2 sec-1 Integrated luminosity = 9.4 pbarn-1 430 nbarn-1/hour -> 10 pbarn-1 per day

  3. KLOE FINUDA SRFF ? SIDDHARTA TODAY 2008?

  4. Starting point for the accelerator Collider e+ e-

  5. It is not possible to meet all the requirements of the collider with present DAFNE hardware • 3 to 4 years from To (project approval) needed for R&D, designing, constructing, testing, installing new components • 1 year commissioning at low luminosity

  6. Do we need to modify completely DAFNE?

  7. Possibility of upgrading the energy in DAFNE up to 2.4 GeV July 2005 Even if the possibility to run also at the Φ-energy is taken into account, optimizing the performance in the low energy range is not considered

  8. Minimum modifications needed for energy upgrade • IR • Dipoles • Splitters • Vacuum chamber • Control system • Diagnostics • Ancillary systems (Injection at 510 MeV keeping the present injection chain)

  9. Different considerations with respect to G-63 are necessary to increase luminosity at F – energy of one order of magnitude

  10. Rf frequency Crossing angle Total current Bunch length xx xy Damping time

  11. Rf frequency Crossing angle Total current Bunch length Lower impedance, higher sE/E, higher ac

  12. Beam-beam tune shift xx xy Damping time

  13. New IR, shorter bunch length, new RF, Lower impedance (e-) New rf system, higher ac, new lattice Shorter damping time, shielded pc, new IR New wigglers New vacuum system

  14. How all these parameters fit in a single machine

  15. One IR • Same detector for all experiments • Flexibility of lattice, all independent quads • New normal conducting dipoles (as in G63) • New sc wigglers • New sc rf system • New layout and vacuum chamber • Upgraded injection system • Future upgrades • Strong rf focusing – sL, b*y in the mm range. • Ring layout not preventing the possibility of installing harmonic and powerful cavity – test can be done in DAFNE in 2007-2008 • (http://www.lnf.infn.it/conference/sbsr05/) • Increase by a factor 4 the luminosity with the same current

  16. IR design

  17. 10° Q2 Q1 KLOE detector for all experiments Transverse plane rotation: Quadrupole rotation different for different energies and/or Bdet Use of SC low beta quads with skew windings No need of mechanical rotation Technology already used in HERA, BEPC, CESR Strong R&D for ILC

  18. IR design parameters

  19. IR optical functions E = 1.2 GeV bx* = 1 m by* = 2 cm qcross = 12 mrad E = 0.51 GeV bx* = 1 m by* = 1 cm qcross = 15 mrad

  20. Parasitic crossing Beam – Beam tune shift E = 0.51 GeV Bunch spacing 60 cm In the first 1.5 m : 5 pc (every 30 cm) E = 1.2 GeV Bunch spacing 3 m First pc after 1.5 m

  21. 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

  22. 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

  23. 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

  24. Wigglers are needed to increase radiation and make beam stronger against instabilities by decreasing damping time Once decided the damping time, I2 is defined: 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

  25. Recent progress in wiggler technology Operating experiences: CESRc, ELETTRA, CAMD Why wigglers are important? • To achieve the short damping times and ultra-low beam emittances needed in LC Damping Rings • To increase the wavelength and/or brightness of emitted radiation in synchrotron light sources • To increase radiation damping and control emittance in colliders R&D in progress: ILC, ATF, PETRA3, … E. Levichev

  26. 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

  27. Wigglers influence beam parameters and dynamics: Change the radiation integrals Non-linear effects: affecting dynamic aperture, lifetime, beam-beam behavior The non linear effects are enhanced if the bunch has large transverse dimensions : Large beta functions and dispersion. Placing wigglers in a non-dispersive zone with low betas minimizes non linear kicks.

  28. 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

  29. 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

  30. 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

  31. Above the microwave instability current threshold sL increases with the current, not depending on ac Short bunch length at high current: • Low impedance • High ac • High voltage MEASUREMENTS ON DAFNE

  32. 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

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

  34. 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 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

  35. SKETCH OF NEW LAYOUT Two rings One IR KLOE Rf cavities wigglers DAFNE HALL

  36. Optical functions at f - energy Wigglers e tuning injection IP

  37. 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

  38. Optical functions at 1.2 GeV

  39. Cryogenic system • KLOE solenoid • Two compensators • 4 low beta quads • 6 wigglers • 2 rf cavities

  40. 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

  41. STUDIES FOR NEW DAFNE INJECTION KICKERS Courtesy of D. Alesini F. Marcellini 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

  42. EVALUATION OF THE KICKER LENGTH (L) AND THE PULSE SHAPE (Lf , Lr) Courtesy of D. Alesini F. Marcellini (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

  43. Injection system • upgrade • The proposed transfer lines pass in existing controlled area • Additional shielding needed in the area between the accumulator and DAFNE buildings new e- line new e+ line

  44. Use of DAFNE2 as Synchrotron light source New scenarios

  45. Tentative costs:41 M euroincluding IVA + 10% contingency 40868800 The option for only energy upgrade: About 22 M euro difference due to Wigglers, rf, cryogenics

  46. Tentative schedule • To -> Project approval (2006) • To + 1 year -> TDR call for tender • To + 2 years -> construction • To + 3 years -> construction and delivery, DAFNE decommissioning • To + 4 years -> installation and commissioning • To + 5 years -> 1st beam for 1st experiment (2011) Different experiments must be planned in temporal sequence since they use the same IR

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