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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 DAFNE upgrade project C. Biscari for the DAFNE team Napoli -19 september 2005
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
KLOE FINUDA SRFF ? SIDDHARTA TODAY 2008?
Starting point for the accelerator Collider e+ e-
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
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
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)
Different considerations with respect to G-63 are necessary to increase luminosity at F – energy of one order of magnitude
Rf frequency Crossing angle Total current Bunch length xx xy Damping time
Rf frequency Crossing angle Total current Bunch length Lower impedance, higher sE/E, higher ac
Beam-beam tune shift xx xy Damping time
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
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
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
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
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
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
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
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
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
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
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
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.
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
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
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
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
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
Touschek beam lifetime and natural bunch length as a function of rf voltage (energy acceptance)
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
SKETCH OF NEW LAYOUT Two rings One IR KLOE Rf cavities wigglers DAFNE HALL
Optical functions at f - energy Wigglers e tuning injection IP
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
Cryogenic system • KLOE solenoid • Two compensators • 4 low beta quads • 6 wigglers • 2 rf cavities
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
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
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=4z inj140mm 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
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
Use of DAFNE2 as Synchrotron light source New scenarios
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
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