1. FAIR accelerator R&D
Oliver Kester GSI Helmholtzzentrum für Schwerionenforschung Darmstadt and IAP Goethe-Universität Frankfurt

2. Introduction Outline Accelerator challenges and R&D Outlook
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

3. FAIR accelerator challenges
Diagnostic and XHV at highest intensities
Superconducting magnets
FLAIR
Rf-cavities
Beam cooling

4. Preparation of the injector chain
Exchange of 35 years old Alverez accelerator
With modern interdigital H-type structures
Higher intensities  28 GHz ECRIS
SIS 18 upgrade
Fast 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
UNILAC upgrade
High power (high intensity),
short pulses
Increase of beam brilliance (Beam current / emittance)
Increase of transported beam currents
Improvements of high current beam diagnostics / operation

5. GSI high current sources
Filament driven
Vacuum Arc driven
High Duty factor
Now let me switch to the main Point of my talk…
By the plasma generation process, HC IS can be devided by…
The Filament dr are…
They produce the gaseous ions
And work with chemically not agressive gases
They desing to produce ME beams
Both types are pulsed and have own advantages and disadvantages.
MUCIS, MUCIS New,
CHORDIS
MEVVA, VARIS
PIG
Working material:
Gases
Metalls and Gases
Metalls and Gases

6. Vacuum Arc Driven Sources
VARIS (Vacuum Arc Ion Source)
Optimized for Uranium (67% of 238U4+)
Emission current density mA/cm2
 kV kV mA in front of the RFQ mA behind the RFQ
Improving the beam quality at plasma extraction
Improvement of beam transport
Lifetime of cathodes
3 Hz operation
Another modification of Vac Arc S is VARIS
It was designed by R. Holl
And optimized for U-beam
For the optimum working conditions it must be HOT

7. 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

8. H-Mode Resonators for LINACs
IH-RFQ
4-vane RFQ
B-Field
B-Field
E-Field
E-Field
IH-Structure
(interdigital H-type)
CH-Structure
(cross bar H-type)

9. 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
MHz
2.1 / 4.2 µm
≤ ± 10-3
4.9 MW
2.5 MW 7 3
≈ 27 m
CH-DTL
Klystron

10. Charge state stripper for intense heavy ion beams
Plasma stripper
- Need to increase the gas density – plasma
window for differential pumping
- Or dense plasma channel separated by
plasma windows
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)
MIT Plasma window in a test setup at BNL

11. Emittance transfer
Reminder:
Bx/y:= (q/A)*Current / Emittancex/y
emittance transfer from horizontal to vertical plane should help to increase the injection efficiency
 transfer should preserve ex*ey

12. The Synchrotron Magnetic field and rf-frequency are ramped synchronous
Dipole
Magnetic field and rf-frequency are
ramped synchronous
to the particle energy.
Quadrupole
Sextupole
bending
correction
focusing
Magnets

13. SIS100 Quadrupole modules
SIS high current (> 4 kA) quadrupoles
SIS100 Injection/Extraction 4 low current (< 1 kA) quadrupoles
A modules comprises:
two quadrupoles,
multipole corrector, steerer, chromaticity sextupole
cryocollimator
beam position monitor (BPM)
Main Characteristics of the
SIS100 quadrupole: B‘ = 27 T/m, Effective length = 1,3 m
Complex system concerning:
Girders, bus bars
helium headers
thermal shield, cryostat
vacuum chamber

14. Cold BPMs Cold beam position monitors In SIS100 quadrupole modules
Signal transfer from 4 K level
to room temperature level QD
BPM ST

15. Cryocatcher in Quadrupole Module
L. Bozyk
SIS100 Qaudrupole Cryostat

16. Dynamic Vacuum effect and collimation
P. Puppel

17. Stacking of particles in the FAIR storage rings
ptrans
circulating, cooled beam t
Circulation time
rf-Barriers
Creation of a gap for injection of
additional particles
New injected bunch
Cooling

18. 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 ms

19. 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