Status of DAFNE2 project

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Status of DAFNE2 project

• C. Biscari

22th LNF Scientific Committee, Frascati, 29th
November 2005
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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

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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
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Past - Present Future
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DAFNE upgradeEnergy and Luminosity Range
K physics Nuclear physics Nucleon form
factors Kaonic nuclei Light source
PHYSICS case afternoon session
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How much we need to modify DAFNE?
IR Vacuum chamber Control system Diagnostics Injec
tion kickers
Wigglers Rf system Feedback Injection
lines Cryogenic system
Dipoles Radiation shielding
High energy
High luminosity
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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
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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
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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
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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
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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
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DAFNE2 quads Gmax 28 T/m
Brett Parker, Snowmass ILC meeting
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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
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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
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Tune scans with BEAM BEAM simulations in
progress to optimize working point and IP
parameters
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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
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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
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DIPOLES
Choice of normal conducting dipoles Maximum
field 1.8 T _at_1.2 GeV I2 2.8 m-1
1.8 T Dipole Magnet, POISSON simulation
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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 (_at_510
MeV) 13 msec I2 26 m-1 Lw 6.5 _at_ B 4
T With same wigglers and scaled dipoles
_at_1.2GeV tx 5 msec I2 6.5 m-1
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Emittance
Wigglers in dispersive zones increase I5 and
emittance depending on b and D
functions. Wigglers in non-dispersive zones
increase I2 and lower emittance
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Wigglers influence beam parameters and
dynamics Change the radiation integrals Non-line
ar 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)
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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
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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
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Collaboration with BINP group
SC Wiggler built at BINP Bmax 7 T for SIBERIAII
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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
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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
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Bunch lengthening with current
Present operating currents (12 - 16 mA)
DAFNE now ZII/n 1.0 W V0.2 MV ZII/n 0.6 W
V0.2 MV

• DAFNE2
• ZII/n 0.6 W
• Higher ac
• Higher sp/p (extra wigglers)
• Higher Voltage (V1.5 MV)
• Ithr 30 mA _at_ 0.51 GeV
• Ithr gt 50 mA _at_1.2 GeV

sz (mm)
Nominal design current (16 mA)
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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
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RF system
Higher frequencies lower acceptance Lower
frequencies higher voltage
A possible candidate cavity 500 MHz SC cavity
operating at KEKB
RD on SC cavities with SRFF experiment in DAFNE
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Touschek beam lifetime and natural bunch
length as a function of rf voltage (energy
acceptance)
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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 - Well in end Going to
2.5 A no expected difficulties for e- While
e-cloud limiting e RD in progress,
simulations, possible cures, possibility of Ti
coating DAFNE vacuum chamber
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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 -gt uniform approach for
longitudinal and transverse 3 - "ALL-IN-ONE",
possibly
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August 05
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Injection system

• Linac Accumulatore OK
• Doubling transfer lines for optimizing ltLgt
• New kickers (RD 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

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STUDIES FOR NEW DAFNE INJECTION KICKERS
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
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Longitudinal rms motion bunch by bunch at
injection e ring (July 2005)
Kicker length
Injected bunch 92
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EVALUATION OF THE KICKER LENGTH (L) AND THE
PULSE SHAPE (Lf , Lr)
GENERATOR REQUIREMENTS (Tnorm0.69mrad.MeV/cm/kV)
Lf - 2LLB4?z inj?140mm LrLf2DB ?1.6m Lets
assume Lr/c300ps
L ? 680mm Lf/c 5ns
Neglecting the bunch length...
L ? 750mm Lf/c 5ns
Lf - 2LLB0
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Optical functions at f - energy
RF
e tuning
Damping Wigglers
Background minimization
injection
IP
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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
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Optical functions at 1.2 GeV
RF
Damping Wigglers
injection
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(No Transcript)
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F. Sgamma
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Tentative schedule

• To -gt TDR and Project approval (2006)
• To 1 year -gt call for tender
• To 2 years -gt construction and delivery
• To 3 years -gt DAFNE decommissioning and
  DAFNE2 installation
• To 4 years -gt 1st beam for commissioning and
• for
  1st experiment (2010)

Different experiments must be planned in temporal
sequence since they use the same IR
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DAFNE - KLOE
KEKB - BELLE