o. kester, jahrestagung des khuk, bad honnef, 30.11.2012 fair accelerator r&d oliver kester gsi...
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O. Kester, Jahrestagung des KHuK, Bad Honnef, 30.11.2012
FAIR accelerator R&D
Oliver KesterGSI Helmholtzzentrum für Schwerionenforschung
Darmstadt and
IAP Goethe-Universität Frankfurt
O. Kester, Jahrestagung des KHuK, Bad Honnef, 30.11.2012
Outline
Introduction Challenges FAIR heavy ion accelerators Preparation of the injectors at GSI
Accelerator challenges and R&D High current ion sources Beam dynamics and cavities Injection / Extraction Cryomodules SIS100
Outlook
Introduction Challenges FAIR heavy ion accelerators Preparation of the injectors at GSI
Accelerator challenges and R&D High current ion sources Beam dynamics and cavities Injection / Extraction Cryomodules SIS100
Outlook
O. Kester, Jahrestagung des KHuK, Bad Honnef, 30.11.2012
FAIR accelerator challenges
FLAIR
Superconducting magnets
Rf-cavities
Beam cooling
Diagnostic and XHV at highest intensities
O. Kester, Jahrestagung des KHuK, Bad Honnef, 30.11.2012
UNILAC upgradeHigh power (high intensity),
short pulses Increase of beam brilliance (Beam
current / emittance) Increase of transported beam currents Improvements of high current beam
diagnostics / operation
SIS 18 upgradeFast ramping, enhanced intensity
per pulse Increase of injection acceptance Improvement of lifetime for low-
charged U-ions Increase of beam-intensity per time
due to reduction of SIS18- cycle time
Exchange of 35 years old Alverez accelerator
With modern interdigital H-type structures
Higher intensities 28 GHz ECRIS
Preparation of the injector chain
O. Kester, Jahrestagung des KHuK, Bad Honnef, 30.11.2012
Filament driven Vacuum Arc driven
MUCIS, MUCIS New,
CHORDIS
MEVVA, VARIS
Working material:
Gases Metalls and Gases
High Duty factor
PIG
Metalls and Gases
GSI high current sources
O. Kester, Jahrestagung des KHuK, Bad Honnef, 30.11.2012
VARIS (Vacuum Arc Ion Source)Optimized for Uranium (67% of 238U4+)
Emission current density
170 mA/cm2
156 mA @ 32 kV
55 mA @ 131 kV
20 mA in front of the RFQ
9 mA behind the RFQ
Vacuum Arc Driven Sources
Improving the beam quality at plasma extraction
Improvement of beam transport Lifetime of cathodes 3 Hz operation
O. Kester, Jahrestagung des KHuK, Bad Honnef, 30.11.2012
UNILAC modifications and the HE-linac
Ion source and beam transport upgrade 4 Alvarez tanks, almost 40 years old exchange by modern IH-structures Charge state stripper technology higher charge states (high intensities) High intensity beam diagnostics
HLI
Stripper und Separator 1.4 MeV/u
ALVAREZ
MUCIS,
MEVVA
PIG
O. Kester, Jahrestagung des KHuK, Bad Honnef, 30.11.2012
H-Mode Resonators for LINACs
E-Field
B-Field B-Field
E-Field
IH-Structure(interdigital H-type)
4-vane RFQIH-RFQ
CH-Structure(cross bar H-type)
O. Kester, Jahrestagung des KHuK, Bad Honnef, 30.11.2012
The FAIR Proton Injector
Beam Energy
Beam Current (design/oper.)
Beam Pulse
Repetition Rate
Frequency
Norm. Emittance at output
Momentum Spread
Beam Loading (peak)
RF Power (peak)
Klystron (3 MW Peak Power)
Solid State Amplifier (50 kW)
Total Length (RFQ + CH)
70 MeV
70 / 35 mA
36 µs
4 Hz
325.224 MHz
2.1 / 4.2 µm
≤ ± 10-3
4.9 MW
2.5 MW
7
3
≈ 27 m
CH-DTL
Klystron
O. Kester, Jahrestagung des KHuK, Bad Honnef, 30.11.2012
Charge state stripper for intense heavy ion beams
C-foil stripper
- short lifetime at highest intensities, but
highest charge states
gas stripper- High intensity capabilities, but lower
charge states
- Equilibrium charge state (efficiency)
10 m
mEdge of the foil before irradiation
Unused foil
Beam inBeam out Beam inBeam out
MIT Plasma window in a test setup at BNL
MIT Plasma window in a test setup at BNL
Plasma stripper- Need to increase the gas density – plasma
window for differential pumping
- Or dense plasma channel separated by
plasma windows
O. Kester, Jahrestagung des KHuK, Bad Honnef, 30.11.2012
Emittance transferT
K3
QS
5
Co
il P
air
TK
3Q
D6
Ver. Chicane skewed triplet
• pepper pottriplet
H3+ 3p
Fo
il S
trip
pe
r
→
0.0
0.4
0.8
1.2
1.6
2.0
2002 2003 2004 2005 2006 2007 2008 2009
Year
Bea
m B
rilli
anz
[em
A /
µm]
hor. achieved (Ar) unstripped
hor. FAIR Design (U73+)ver. achieved (Ar) unstripped
ver. FAIR Design (U73+)
Future
Ex*Ey = const
Reminder:
Bx/y:= (q/A)*Current / Emittancex/y
emittance transfer from horizontalto vertical plane should help to increase the injection efficiency
transfer should preserve xy
O. Kester, Jahrestagung des KHuK, Bad Honnef, 30.11.2012
The Synchrotron
QuadrupoleQuadrupole
Sextupole
bending
correction
focusing
Magnetic field and rf-frequency areramped synchronousto the particle energy.
Magnetic field and rf-frequency areramped synchronousto the particle energy.
MagnetsMagnets
Dipole
qvBr
mv
2
O. Kester, Jahrestagung des KHuK, Bad Honnef, 30.11.2012
SIS100 169 high current (> 4 kA) quadrupolesSIS100 Injection/Extraction 4 low current (< 1 kA) quadrupoles
Main Characteristics of the SIS100 quadrupole:B‘ = 27 T/m, Effective length = 1,3 m
A modules comprises:
• two quadrupoles,• multipole corrector, steerer,
chromaticity sextupole• cryocollimator• beam position monitor (BPM)
Complex system concerning:• Girders, bus bars• helium headers• thermal shield, cryostat• vacuum chamber
SIS100 Quadrupole modules
O. Kester, Jahrestagung des KHuK, Bad Honnef, 30.11.2012
Cold beam position monitorsIn SIS100 quadrupole modules
Signal transfer from 4 K levelto room temperature level
Cold BPMs
QDQD BPMBPM STST QDQD
O. Kester, Jahrestagung des KHuK, Bad Honnef, 30.11.2012
Cryocatcher in Quadrupole Module
SIS100 Qaudrupole Cryostat L. Bozyk
O. Kester, Jahrestagung des KHuK, Bad Honnef, 30.11.2012
Dynamic Vacuum effect and collimation
P. PuppelDipole
Target-Ionisation
Projectile-Ionisation
Coulomb-Scattering,Intra-Beam-Scattering
Desorption
adsorbed residual gas
U29+
Solid Body
Adsorbed Residual Gas
Desorbed Gas
O. Kester, Jahrestagung des KHuK, Bad Honnef, 30.11.2012
0 10 20 30 40 50 60 70 80 90 1000.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
I E
SR
/
I SIS
t (s)
ptrans
t
circulating, cooled beam
rf-Barriers
Creation of a gap for injection of additional particles
New injected bunch
Cooling
Circulation time
Stacking of particles in the FAIR storage rings
O. Kester, Jahrestagung des KHuK, Bad Honnef, 30.11.2012
Fast bunch rotation in the CR
Challenges:• Short bunch from SIS100 (50 ns)
• For stochastic cooling de-bunching required
• High voltage (200 kV) required for fast rotation and reduction of momentum spread after production target
Gap voltage 40 kV
Length 1 m
Rotation time ~ 100 s
O. Kester, Jahrestagung des KHuK, Bad Honnef, 30.11.2012
Summary FAIR accelerator developments
High current ion sources and optimized beam transport
Cavity development for LINACS – H-type cavities
p-Linac and HE-Linac
Charge state stripper technologies
Emittance transfer – injection into synchrotrons
Cryogenic SIS100 modules and dynamic vacuum effect Accumulation of secondary particles via barrier
bucket injection
High current ion sources and optimized beam transport
Cavity development for LINACS – H-type cavities
p-Linac and HE-Linac
Charge state stripper technologies
Emittance transfer – injection into synchrotrons
Cryogenic SIS100 modules and dynamic vacuum effect Accumulation of secondary particles via barrier
bucket injection