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Georg Bollen Michigan State University

ReA12 -Update. Georg Bollen Michigan State University.

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Georg Bollen Michigan State University

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  1. ReA12 -Update Georg BollenMichigan State University • D. Leitner, D. Alt, T. M.Baumann, C. Benatti, B. Durickovich, K. Kittimanapun, A. Lapierre, L. Ling-Ying, S. Krause, F. Montes, D. Morrissey, S. Nash, R. Rencsok, A. Rodriguez, C. Sumithrarachchi, S. Steiner, S. Schwarz, M. Syphers, S. Williams, W. Wittmer, X. Wu and others

  2. Facility for Rare Isotope BeamsFast, Stopped, and Reaccelerated Beams for Science ReAccelerator Facility • Rare isotope production via in-flight technique with primary beams up to 400 kW, 200 MeV/u uranium • Fast, stopped and reaccelerated beam capability • NSCL will provide pre-FRIB science opportunities with fast, stopped and reaccelerated beams • New equipment must integrate into FRIB in the future G. Bollen, Recoil Separator for ReA12Workshop, MSU 2014

  3. FRIB Construction Underway • FRIB project completion in 2022 • managed to early completion in 2020

  4. NSCL only Facility in the World that ProvidesFast, Stopped, and Reaccelerated Beams of Rare Isotopes SECAR (design) JENSA ANASEN, FSU SuNCFFDJANUS.. Cycstopper off line commissioning BECOLA AT-TPC 20 meter MoNA LISA LEBIT, Minitrap Sweeper Magnet Momentum Compression Beam Line) ReA3 Hall K500 Cyclotron Gas Stopper ReA6-12 Hall ReAccelerator Facility Space for future expansion of the science program SEETF K1200 Cyclotron SeGA HiRA Triplex Plunger CAESAR LENDA GRETINA (DOE national user facility) BCS NERO DDAS CAESAR S800 A1900 Fragment Separator RFFS Gas Stopper Fast Beams Stopped beams Reaccelerated Beams G. Bollen, Recoil Separator for ReA12Workshop, MSU 2014

  5. In-flight Fragmentation Offers A Wide Variety Of Rare Isotopes CCF NSCL’s Coupled Cyclotron Facility has produced >1000 RIBs and >870 RIBs have been used in experiments with > 90% availability FRIB FRIB will provide 1000-10000 times higher beam rates

  6. Fast Rare Isotope Beam Production at NSCL and FRIB CCF FRIB • 1000x higher primary beam power G. Bollen, Recoil Separator for ReA12Workshop, MSU 2014

  7. The ReAccelerator (ReA)From fast to stopped to reaccelerated beams Highly chargedionbeam, 12 keV/u x A (2≤A/Q≤5) 12 keV/u 600 keV/u RB 80.5 MHz b=4.1% b=8.5% A few MeV’s/u Magnetic sector Room-temperature RFQ Superconducting RF linac Achromatic Q/A separator • Continuous injection (currently) & accumulation (~1 s - 200 ms) • Pulsed extraction (~ 1 - 50 Hz) MHB Electrostatic sector Trapped ions ~ 200 eV EBIT charge breeder 1+ Q+ ≤ 60 keV **Production & In-flight separation <1 eV > 80 MeV/u Thin foil target Initial configuration, ReA3: He gas-cell Continuous stable heavy ion beam>80 MeV/u • 48Ca 0.3 - 6 MeV/u 238U 0.3 - 3 MeV/u “Stopping” area Finalconfiguration, ReA12 • 48Ca 0.3 - 20 MeV/u 238U 0.3 - 12 MeV/u G. Bollen, Recoil Separator for ReA12Workshop, MSU 2014

  8. Stopped Beam FacilitiesReady to Deliver Beams Si detector to measure b-decay activity for particle ID & beam transport optimization • Purpose of beam stopping: • Decelerate the rare-isotope beams • Reduce the emittance for reacceleration Si detectors to measure b-decay activity for particle ID & beam transport optimization Thermalizaeiosn in gas cellwith helium as a buffer gas Rare-isotope beams from the production area DC beams > 80 MeV/u DC beams, up to60 keV Analyzing dipole magnet G. Bollen, Recoil Separator for ReA12Workshop, MSU 2014

  9. Stopped Beam FacilitiesContinuing Upgrades • Multifaceted approach • Linear gas stopper (heavier ion beams) • Cyclotron gas stopper (lighter ion beams) • Solid stopper (certain elements, highest intensity) • Cyclotron gas stopper well underway • Yoke, poles, coils, cryostat fabricated, stopping chambermanufactured. System assembled • Cool down of magnet started • Ion transport and extraction techniques demonstrated • Cryogenic linear gas stopper • Higher beam purity, faster extraction, higher beam rates • NSF-MRI funding (information received) G. Bollen, Recoil Separator for ReA12Workshop, MSU 2014

  10. Re-Accelerator ReAState-Of-The-Art RIB Post-Accelerator and the First Coupled toA Fragmentation Facility CM1 EBIT CB RFQ CM2 SECAR CM3 (2014) General Purpose Line D-Line N4 Stopped beams A1900 ReA3 AT-TPC L-Line 2010/10: RFQ commissioning started 2011/04: CM1 first beam acceleration 2011/06: CM2 first beam acceleration 2012/04: first 1+-n+ acceleration 2013/06: Experimental hall beam line 2013/08: First rare isotope experiment 2014/05: Cryomodule 3 installation ReA6 ReA6 Equipment & Beamlines TBD G. Bollen, Recoil Separator for ReA12Workshop, MSU 2014

  11. ReA Will Provide World Unique BeamsTop Energies (ReA3 to ReA12) “n-rich” “n-deficient” Measured cavity performance Original cavity performance Measured cavity performance Measured cavity performance Original cavity performance ReA energy upgrade continues to be a key user demand G. Bollen, Recoil Separator for ReA12Workshop, MSU 2014

  12. ReADesign Choices: EBIT Charge Breeder Achromatic Mass Separator Pilot source for linac tuning MHB 0.041 modules RT RFQ 0.085 module FY14 n+ RIB beam EBIT 1+ RIB beam • EBIT: • Short breeding time • High ionization efficiency • Charge state flexibility • Low beam contamination • 0.5 ≥ Q/A ≥ 0.2 G. Bollen, Recoil Separator for ReA12Workshop, MSU 2014

  13. Charge Breeding In The EBIT Source Continuous injection and accumulation (~100 ms) A+ Electron beam Magnetic field Electron collector Trap electrodes Electron gun Pulsed extraction (msto ms) AQ+ Highly charged ions Radial electron-beam space-charge potential Axial potential well from the trap electrodes Lower-the-barrier extraction Over-the-potential barrier injection V V 1+ 1+ 1+ 1 q+ q+ 2+ 2+ Continuous injection Pulsed extraction G. Bollen, Recoil Separator for ReA12Workshop, MSU 2014

  14. Measured Charge Breeding Efficiency Efficiency in single charge states of injected 39K stable-isotope beams ReA EBIT not yet operated at full current G. Bollen, Recoil Separator for ReA12Workshop, MSU 2014

  15. Improving EBIT Efficiency with Beam Bunching Dynamic capture of ion bunch doesn’t rely on 1+ 2+ charge breeding • Continuous injection into EBIT charge breeder • Ultimately needed for highest beam intensity (FRIB) • 30% efficiency (for all charge states) demonstrated with present electron gun • In-flight capture of ion bunches increases efficiency • Capture efficiency ecapt= 30% (DC)  ecapt = 100% (pulsed) • Higher efficiency for breeding into single charges state • Reduced breeding times • New beam buncher is under construction • Cryogenic cooler and buncher based on gas filled RFQ ion trap • Optimized for fast cooling and bunching (<100ms) • Optimized for high rate capability (107 ions per bunch  108 ions/s) - compatible with NSCL’s CCF beam rates • Status • Assembly underway • Start commissioning in fall 2013 2014 G. Bollen, Recoil Separator for ReA12Workshop, MSU 2014

  16. ReA Design Choices: RT-RFQ With External Buncher And High Efficiency SC-Linac Pilot source Q/A MHB 0.041 modules RT RFQ 0.085 module FY14 n+ RIB beam EBIT 1+ RIB beam • SRF LINAC • 80.5 MHz RF frequency • Flexible energy range (deceleration 300keV/u to maximum linac energy in small steps • External multi harmonic buncher to minimize the longitudinal emittance G. Bollen, Recoil Separator for ReA12Workshop, MSU 2014

  17. Room Temperature Radio Frequency Quadrupole (RFQ) • Pulsed operation (160kW, 25%) • Energy Boost: 12 keV/u - 600 keV/u • 4-rod structure, 92 cells, 3.3 m long • Buncher : 80.5MHz, 161MHz, (241.5 MHz) • Nom 82 % beam capture measured MHB Longitudinal acceptance (white area) Beam bunch after RFQ Beam at the entrance of RFQ G. Bollen, Recoil Separator for ReA12Workshop, MSU 2014

  18. Cryomodule 3 Makes ReA3 CompleteInstallation on Platform Started • Ten β=0.085 cavities were redesigned to reliably provide high gradient acceleration fields Cryomodule 3 • CM4 (FRIB prototype phase I, 2014) G. Bollen, Recoil Separator for ReA12Workshop, MSU 2014

  19. Reaccelerator Testing with Pilot Beam CM1 EBIT CB Low Energy Experimental hall RFQ CM2 SECAR CM3 (2014) First RIB beam delivered D-Line N4 Stopped beams A1900 AT-TPC Charge Bred Beam Rb+ → Rb28+ from the EBIT Pilot Beam Linac transmission RIB beams ≈ 70% G. Bollen, Recoil Separator for ReA12Workshop, MSU 2014

  20. Experimental Equipment for ReA3Installation Started in May 2013 At-TPC Line First radioactive beam experiment with ReA3 (8/2013) ANASEN Detector JENSA Gas Jet Target (SECAR) G. Bollen, Recoil Separator for ReA12Workshop, MSU 2014

  21. Optimizing ReABeam Time StructureInvestigating Different Beam Scenario with EBIT • EBIT provides flexibility in time structure of extracted beams, ranging from release of very short to long pulses. • 2nd EBIT would provide option for near continuous beam. • Study of extraction of very short pulses (50 ns) underway  D. Bazin G. Bollen, Recoil Separator for ReA12Workshop, MSU 2014

  22. Optimizing ReABeam Time StructureInvestigating ReA Bunch Spacing Options  D. Bazin • With 80.5 MHz ReA components, bunch spacing is 12.4 ns • TOF experiments require larger bunch spacing • Designing 16 MHz “pre-buncher” RFQ 3D EM design of PB electrodes EBIT • Proposing different frequency re-buncher after RFQ or Linac to remove “satellite” bunches • Can create continuous 62 ns spacing; a pulsed EBIT in conjunction would allow greater spacing (Alt, Syphers, et al.) G. Bollen, Recoil Separator for ReA12Workshop, MSU 2014

  23. Optimizing ReABeam Time StructureInvestigating ReA Bunch Spacing Options • Very short pulses  50 ns from EBIT • No principal show stopper to reach very short pulses (50 ns) • Being investigated • May require trap electrode optimization • Maximizing beam throughput • Extraction pulse length determines number of ions • Desired repetition rate may not empty EBIT before next injection/breeding cycle • May require trap electrode optimization and more sophisticated in trap ion gymnastics G. Bollen, Recoil Separator for ReA12Workshop, MSU 2014

  24. Summary • ReA is the first re-accelerator coupled to a fragmentation facility • First reaccelerated radioactive ion beam to users was delivered 8/2013 • Beam stopping commissioned and being upgraded • Linear gas catcher (FRIB R&D provided by ANL) operational and improved • Cyclotron gas stopper construction underway • Linear cryogenic gas cell development scheduled for funding • Charge breeding • Demonstrated and efficiencies good starting point • Parallel approach to further increase efficiencies • Adding dedicated cryogenic beam cooler and buncher • Increasing current densities • Accelerator • Better-than-design performance • 3rd cryomodule assembled and being installed  ReA3 nears completion • Adding more β=0.085 cryomodules will lead to ReA12 • ReA has significant potential to taylor beam properties to experiment needs • Developments are under way G. Bollen, Recoil Separator for ReA12Workshop, MSU 2014

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