the design and commissioning of the accelerator system of ... · – understanding pairing, shapes,...
TRANSCRIPT
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C.K. Gelbke, March 2012, KoRIA Team Visit, Slide 1
The Design and Commissioning of the Accelerator System of the Rare Isotope
Re-accelerator - ReA3Xiaoyu WuNSCL/FRIB
Michigan State University
On Behalf of the ReA3 Team
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X. Wu, September 18, 2012, HB2012, Slide 2
NSCL and FRIB Laboratory at Michigan State University
• NSCL is funded by the U.S. National Science Foundation as a user facility to produce rare isotope beams for research and education in nuclear science, nuclear astrophysics, accelerator physics, and societal applications
• FRIB, currently being designed and established at MSU, will be a national user facility funded by the U.S. Department of Energy Office of Science
• NSCL will transition into FRIB eventually
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X. Wu, September 18, 2012, HB2012, Slide 3
Rare Isotope Beam Productions by Projectile Fragmentation
• Modest beam quality and high beam energy(E/A ~ 100 MeV/u)
• Suitable for short-lived isotopes (τ > 10-6 s)
• Physical method of separation, no chemistry
• High quality, low-energy beams are difficult (emittance too large)
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X. Wu, September 18, 2012, HB2012, Slide 4
Strong Demands for High Quality, Low-Energy RIBs
• Nuclear astrophysics – Better interpretation of X-ray bursts and novae observations– Origin of p-nuclei– Supernovae modeling
• High quality low energy RIBs allow:– Reaction measurements at astrophysical energies– Indirect techniques to obtain astrophysical rates
• Nuclear physics – Shell structure evolution away from stability– Understanding pairing, shapes, cluster structure and collectivity of exotic nuclei– Reaction of exotic nuclei
• High quality low energy RIBs allow:– Transfer reactions– Multi-step Coulomb excitation– Fusion evaporation reactions
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X. Wu, September 18, 2012, HB2012, Slide 5
Current NSCL Facility Layout
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X. Wu, September 18, 2012, HB2012, Slide 6
Future FRIB Layout
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X. Wu, September 18, 2012, HB2012, Slide 7
3MeV/u Re-accelerator - ReA3 Layout
LEBTRFQ
Q/A Selection
EBITSC Linac
ReA3 Beam Distribution Line
AT-TPCANASEN
SECAR
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X. Wu, September 18, 2012, HB2012, Slide 8
LEBT/RFQO
fflin
e Io
n S
ourc
e(4
He1
+ )
Bunch length monitor
RFQ
Mul
ti-ha
rmon
ic
bunc
her
CaF viewer
Faraday cup
Beam transport to the RFQ: Beam bunching Transverse
beam matching
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X. Wu, September 18, 2012, HB2012, Slide 9
ReA3 SRF Cryomodules
ReA3 -• 3 ReA3 Cryomodules• 15 cavities• 2 cavity types (QWR)
– Beta=0.041 & 0.085– Prototypes for FRIB
• 8 solenoids– Same as used in FRIB
• 1st two cryomodules installedIn 2010• 3rd cryomodule under development, will be installedEarly 2013
β = 0.041 modules
β = 0.085 module
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X. Wu, September 18, 2012, HB2012, Slide 10
Design Changes of β=0.085 QWR
• Old design modified to improve performance reliability
• New design of the rf joint
• Rf couplers moved to the side
• Increased distance from inner conductor to tuning plate
Both ReA3 and FRIB requirements more than fulfilled in testing naked cavities with the new rf joint design and side coupler
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X. Wu, September 18, 2012, HB2012, Slide 11
ReA3 beam Distribution Line
Single cavity rebunching cryomodule
Achromatic S-Bend
High resolution 90° achromatic bend with slit
Final focusing systems
Switchyard
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X. Wu, September 18, 2012, HB2012, Slide 12
ReA3 Beam Dynamics Simulations (1)Maintain beam quality – minimize emittance growth
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X. Wu, September 18, 2012, HB2012, Slide 13
ReA3 Beam Dynamics Simulations (2)Meeting beam-on-target requirements
Beam size: ~ 2mmEnergy spread: ~ 1 keV/uBunch length: ~ 1 ns
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X. Wu, September 18, 2012, HB2012, Slide 14
ReA3 Commissioning ongoing
Two beta=0.041 Cryomodules
RFQLEBT
Q/A Selection
EBIT
L-Line Deck Extension
RFQ2.344 MeV
6.168 MeV
α-source 5.486 MeV
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X. Wu, September 18, 2012, HB2012, Slide 15
Energy Upgrade Phase I - ReA6
ReA3
ReA6EBIT
ReA3 ExperimentalHall
ReA6 ExperimentalHall(s)
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X. Wu, September 18, 2012, HB2012, Slide 16
ReA6 Accelerating Cryomodules
• 4th generation beta=0.085 QWR cavities• 8 cavities• 3 SC solenoid magnets
with X/Y dipole correctors• 3 Cold beam position
monitors • ~ 6 m long• FRIB Linac Segment I will
use same cryomodules (11)
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X. Wu, September 18, 2012, HB2012, Slide 17
ReA6 Beam Dynamics Simulations (1)Maintain beam quality – minimize emittance growth
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X. Wu, September 18, 2012, HB2012, Slide 18
ReA6 Beam Dynamics Simulations (2)Meeting beam-on-target requirements
Beam size: ~ 2mmEnergy spread: ~ 1 keV/uBunch length: ~ 1 ns
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X. Wu, September 18, 2012, HB2012, Slide 19
Energy Upgrade Phase II - ReA12
ReA3
ReA12EBIT Charge Breeder
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X. Wu, September 18, 2012, HB2012, Slide 20
ReA3/ReA6/ReA12 Performance
0
5
10
15
20
25
0.1 0.2 0.3 0.4 0.5 0.6
Ek (M
eV/u
)
Q/A
ReA3
ReA6
ReA12
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X. Wu, September 18, 2012, HB2012, Slide 21
Summary
• The Re-Accelerators at the NSCL will provide a new low energy high quality RIBs facility for nuclear astrophysics and nuclear science.
• Construction and commissioning underway.
• Installation of ReA3 completed FY2013
• Radioactive ion beam commissioning runs 2013
• First beamline into ReA3 hall 5/2013
• Energy upgrade phase I started– ReA6 Cryomodule fabrication has started, completion planned 2014
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