Status of DAFNE upgrade project C Biscari for
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. Energy (cm) (Ge. V) Integrated Luminosity per year (ftbarn-1) Total integrated luminosity Peak luminosity > (cm-1 sec-2) 1. 02 2. 4 8 20 3 8 1032
• 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 2006 2007 2008 2009 2010 2011 To - Design + Construction + Delivery + Decommissioning + Installation First beam to 1 st experiment
Do we need to modify completely DAFNE?
Possibility of upgrading the energy in DAFNE up to 2. 4 Ge. V 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 Me. V 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 Now New Frf (MHz) 368 500 Bunch spacing (cm) 84 60 Bunch spacing (nsec) 2. 5 1. 8 h 120 165 Nb 110 150 Itot (A) 1. 3+ 1. 8 - 2. 5 Vmax (MV) 0. 25 1. 5 ac max 0. 04 0. 08 I Boussard (m. A) 1 15 l (cm) @ 15 m. A 2 -3 1 Bunch length Lower impedance, higher E/E, higher ac
Beam-beam tune shift xx xy Damping time
Now New N (1010 ) 2. 4 – 3. 3 3. 4 - 3. 4 I (A) 1. 3 – 1. 8 2. 5 - 2. 5 ex (m rad) 0. 4 0. 3 bx ( m ) 1. 8 1 by ( cm ) 1. 8 1 L (cm) 2 -3 1 k(%) 1. 5 1 td ( msec ) 37 12 I 2 ( 10 30 Uo ( ke. V ) 9 27 P ( k. W ) 9 x 5 A 27 x 2. 5 A m-1 ) 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
How all these parameters fit in a single machine
• • One IR Same detector for all experiments Flexibility of lattice, all independent quads New normal conducting dipoles (as in G 63) New sc wigglers New sc rf system New layout and vacuum chamber Upgraded injection system Future upgrades • Strong rf focusing – L, 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/sbsr 05/) • Increase by a factor 4 the luminosity with the same current
IR design
KLOE detector for all experiments Energy (Ge. V) 0. 51 1. 2 Bdet (T) 0. 4 0. 2 BL (Tm) 1. 68 0. 84 qrot (°) 28. 3 6. 0 Transverse plane rotation: Quadrupole rotation different for different energies and/or Bdet Use of SC low beta quads with skew windings 10° No need of mechanical rotation Technology already used in HERA, BEPC, CESR Strong R&D for ILC Q 2 Q 1
IR design parameters
IR optical functions E = 0. 51 Ge. V bx * = 1 m by* = 1 cm qcross = 15 mrad E = 1. 2 Ge. V bx * = 1 m by* = 2 cm qcross = 12 mrad
Parasitic crossing Beam – Beam tune shift E = 0. 51 Ge. V E = 1. 2 Ge. V Bunch spacing 60 cm In the first 1. 5 m : 5 pc (every 30 cm) Bunch spacing 3 m First pc after 1. 5 m
Choice of lattice, dipoles, wigglers Synchrotron radiation integrals Emittance - I 2, I 4, I 5 Damping time - I 2 Energy spread - I 3, I 4 Natural bunch length - I 3, I 4 Emitted power - I 2
Damping time and radiation emission Energy emitted per turn Damping time In DAFNE now: I 2 = 9. 5 m-1 , Uo = 9 ke. V, tx = 37 msec I 2 = 4. 5 dipoles + 5 wigglers
DIPOLES Choice of normal conducting dipoles Maximum field: 1. 8 T @1. 2 Ge. V I 2 = 2. 8 m-1 1. 8 T Dipole Magnet, POISSON simulation Dipoles per ring 12 B (T) 0. 77 – 1. 8 r (m) 2. 22 Gap (cm) 3 Angle (°) 26. 6(5) 33. 3(5) 37. 3(1) 22. 6(1) Magnetic length (m) Current (A) 1. 03 (5) 1. 29 (5) 1. 45 (1) 0. 88 (1) 150, 430
Wigglers are needed to increase radiation and make beam stronger againstabilities by decreasing damping time Once decided the damping time, I 2 is defined: In our case: tx (@510 Me. V) = 13 msec : I 2 = 26 m-1 Lw = 6. 5 @ B = 4 T With same wigglers and scaled dipoles @1. 2 Ge. V: tx =5 msec I 2 = 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 E. Levichev R&D in progress: ILC, ATF, PETRA 3, …
Emittance Dispersion D D W I 5 Wigglers in dispersive zones increase I 5 and emittance depending on b and D functions. Wigglers in non-dispersive zones increase I 2 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.
Choice of wiggler shape Good field region centered around wiggler axis Usual wiggler design: odd # poles CESRc design: even # poles E = 0. 51 Ge. V E = 1. 2 Ge. V B=4 T Trajectory position with respect to wiggler axis, depends on E and B B=4 T 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 L 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) E (Ge. V) 0. 51 1. 2 E/E (10 -4) 6. 1 8. 4 ac 0. 08 0. 04
High currents NOW: I- = 1. 8 A I+ = 1. 3 A routinely Maximum stored current: I- = 2. 4 A I+ = 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
F N-N Energy per beam E Ge. V 0. 51 1. 2 Circumference C m 100 Luminosity L cm-2 sec-1 8 1032 Current per beam I A 2. 5 0. 5 150 30 N of bunches Nb Particles per bunch N 1010 3. 1 3. 4 Emittance e mm mrad 0. 3 0. 6 Horizontal beta* bx m 1 1 Vertical beta* by cm 1 2 Bunch length s. L cm 1 2 Coupling k % 1 1 Energy lost per turn Uo (ke. V) 25 189 H damping time tx (msec) 13 5 Beam Power Pw (k. W) 62 (55 w + 7 d) 94. 6 (42 w + 53 d) Pw/m (k. W/m) 8. 6 w + 0. 5 d 8. 4 w + 3. 8 d Power per meter
SKETCH OF NEW LAYOUT Two rings One IR KLOE wigglers Rf cavities DAFNE HALL
Optical functions at f - energy e tuning Wigglers injection IP
IR + section for background minimization DIPOLE Beam direction 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
Optical functions at 1. 2 Ge. V
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 Schematic of the present F. Marcellini injection kicker system and kicker structure K K 2 kickers for each ring ~ 10 mrad Beam pipe radius = 44 mm Kicker length = 1 m E=510 Mev # of bunches=120(max) Stored current=1. 5 -2. 0 A VT VT present pulse length ~150 ns t aimed FWHM pulse length ~5. 4 ns t
VIN Deflecting voltage VT EVALUATION OF THE KICKER LENGTH (L) AND THE PULSE SHAPE (Lf , Lr) Generator pulse shape Lf /c t Lr /c Courtesy of D. Alesini F. Marcellini (Lf-2 L)/c=LB/c 2 DB (2 L+Lr)/c t (2 L+Lr)/c GENERATOR REQUIREMENTS (Θnorm=0. 69 mrad. Me. V/cm/k. V Lf - 2 L=LB=4 z inj 140 mm Beam energy Lr+Lf=2 DB 1. 6 m Let’s assume: Lr/c=300 ps Angle of deflection L 680 mm Lf/c = 5 ns 510 Me. V 6 mrad Stripline length 68 cm Stripline radius (optimized covarage angle) 30 mm Required voltage from pulse generator ~65 k. V Average power (max rep. rate 50 Hz) 24. 5 W Pulser output current 1400 A Neglecting the bunch length. . . Lf - 2 L=LB=0 L 750 mm Lf/c = 5 ns Stripline length Required voltage from pulse generator 75 cm ~45 k. V
Injection system upgrade new e- line • The proposed transfer lines pass in existing controlled area • Additional shielding needed in the area between the accumulator and DAFNE buildings new e+ line
Use of DAFNE 2 as Synchrotron light source New scenarios Energy (Ge. V) 0. 51 1. 2 Current (A) 2. 5 0. 5 B dipoles (T) 0. 77 1. 8 B wigglers (T) 4.
Tentative costs: 41 M euro including IVA + 10% contingency 40868800 The option for only energy upgrade: About 22 M euro difference due to Wigglers, rf, cryogenics
Tentative schedule • To + 1 year -> -> • To + 2 years • To + 3 years -> -> • To + 4 years • To + 5 years (2011) -> -> Project approval (2006) TDR call for tender construction and delivery, DAFNE decommissioning installation and commissioning 1 st beam for 1 st experiment Different experiments must be planned in temporal sequence since they use the same IR
manpower • • • • • • • Richiesta di personale in vista dei programmi futuri Servizio Elettronica e Diagnostica N. 1 Fisico o Ingegnere Elettronico N. 1 Diplomato in Elettronica Servizio Impianti a Fluido N. 2 Diplomati Impiantisti Servizio Impianti Criogenici Servizio Impianti di Potenza e Magneti N. 2 Ingegneri N. 2 Diplomati Elettrotecnica-Elettronica Servizio Impianti Elettrici N. 1 Diplomato Elettrotecnico Servizio Ingegneria Meccanica N. 1 Ingegnere Meccanico N. 2 Diplomati Progettisti Meccanici Sevizio Linac e Sicurezze N. 1 Fisico o Ingegnere Elettronico RF N. 2 Diplomati Elettrotecnica-Elettronica Servizio Radiofrequenza Servizio Sistema di Controllo N. 2 Fisici o Ingegneri Informatici N. 1 Diplomato Informatica Servizio Vuoto N. 1 Fisico o Ingegnere dei Materiali N. 1 Diplomato Impiantista Per il gruppo di fisica di macchina è inoltre necessario un rinforzo di almeno un paio di giovani fisici. D. A. + 10 Physicists – Engineers 12 Technicians
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