ReA3 Marc Doleans (On behalf of the ReA3 team)

Transcription

1 ReA3 Marc Doleans (On behalf of the ReA3 team) HIAT09, 08/06/2009, Slide 1

2 Building addition Office building (~100 staff + conf. rooms) ReA3 Experimental area 9100 sqft HIAT09, 08/06/2009, Slide 2

3 Why reaccelerated beams at the NSCL? NSCL is a user facility based on rare isotope production by projectile fragmentation and projectile fission NSCL has successful program with stopped beams LEBIT facility for Penning trap mass spectrometry of projectile fragments laser spectroscopy under preparation More than 900 RIBs have been made more than 600 RIBs have been used in experiments ReA3 opens new science opportunities with rare isotopes produced by projectile fragmentation Nuclear astrophysics: key reactions at near-stellar energies Nuclear structure via Coulomb excitation or transfer reactions HIAT09, 08/06/2009, Slide 3

4 Reaccelerated beams at FRIB at MSU FRIB includes fast (F), stopped (S), and reaccelerated beams (R). ReA3 provides pioneering beams for research in one of the pillars of FRIB. ReA3 will allow the user community to develop programs and techniques in reaccelerated beams before FRIB will come into operation. HIAT09, 08/06/2009, Slide 4

5 ReA3 at the Coupled Cyclotron Facility Coupled cyclotrons primary beams : ~ 150 MeV/u ReA3 beams : Up to 3 MeV/u for Q/A=1/4 Building addition Coupled cyclotrons A1900 Fragment separator HIAT09, 08/06/2009, Slide 5

6 ReA3 concept and overview Goal: provide optimized reaccelerator for maximum science reach > 50 MeV/u Beams Charge Breeder Multi Harmonic Buncher 80 MHz RFQ 80 MHz SRF β=4.1% 80 MHz SRF β=8.5% Gas stopper Mass separator 1 + N + Q/A Separator Next generation gas stopping Various optimized stopping techniques Multiple stations in future to avoid single-point failure Advanced n+ reacceleration scheme to maximize science reach; best achieved with an EBIT charge breeder Maximize efficiency by avoiding stripping losses Provide variable duty factor to tailor beam to experiments Deliver clean beams to avoid background and ambiguities Sufficient and expandable space for experiments HIAT09, 08/06/2009, Slide 6

7 ReA3 at the Coupled Cyclotron Facility 3 MeV/u experimental area Layout plan Stopped beam area - Relocated LEBIT - Laser spectroscopy N4 beam stopping vault LINAC EBIT charge breeder HIAT09, 08/06/2009, Slide 7

8 Gas cells Vault reconfiguration in new momentum compression beam lines + solid stopper line Opportunity for simultaneous R&D and beam operation for pre-frib science (ReA3, stopped beams) Phase 1 (before 2012): ANL gas catcher and MSU linear cryogenic gas stopper Phase 2 (after 2012): Cyclotron gas stopper and linear gas stopper Phase 1 Cyclotron gas stopper Task Task leaders: leaders: D. D. Morrissey, Morrissey, G. G. Bollen Bollen collaboration collaboration with with ANL ANL Phase 2 HIAT09, 08/06/2009, Slide 8

9 ReA3 reacceleration Q/A separator 12 kev/u RFQ Collaboration with: with: MPI K Heidelberg, Univ. Univ. Frankfurt, INFN INFN Legnaro, TRIUMF, IPN IPN Orsay 600 kev/u SRF linac EBIT Charge breeder Compact and efficient re-acceleration EBIT charge breeder & Q/A separator Radio-frequency quadrupole (RFQ) Superconducting linac Energy examples: 238 U MeV/u 48 Ca MeV/u HIAT09, 08/06/2009, Slide 9

10 ReA3 - platform Q/A separator LEBT stable source RFQ SRF linac EBIT room HIAT09, 08/06/2009, Slide 10

11 ReA3 platform HIAT09, 08/06/2009, Slide 11

12 High-current EBIT charge breeder Task Task leaders: leaders: S. S. Schwarz, Schwarz, G. G. Bollen Bollen High performance : Large trapping region 80 cm High e-e beam current >2.5 A High e-e current density >10 4 A/cm 2 Strong magnetic field 6 T Features: Continuous injection of ions» high capture rate Variable extraction duty cycle» μs s pulse to quasi-continuous Short breeding time (<10 ms) Highest efficiency» > 50% in a single charge state HIAT09, 08/06/2009, Slide 12

13 High-current EBIT charge breeder Task Task leaders: leaders: S. S. Schwarz, Schwarz, G. G. Bollen Bollen High performance : Large trapping region 80 cm High e- beam current >2.5 A High e- current density >10 4 A/cm 2 Strong magnetic field 6 T EBIT charge breeder concept successfully used at REX-ISOLDE CERN RHIC-EBIS provides intense pulses of highly-charged heavy ions Preliminary tests with temporary 0.4 T solenoid magnets achieved 0.3 A with 98% transmission to the collector e- collector e- gun 0.4 T test magnets HIAT09, 08/06/2009, Slide 13

14 LEBT beam dynamics Energy Design beam Parameters 12 kev/u Q/A ε x,y (100%) 0.6 π μm ΔE ± 0.2 % HIAT09, 08/06/2009, Slide 14

15 Electrostatic quads LEBT Stable Ion Source ( 4 He 1+ ) Multi-harmonic buncher Bunch length monitor RFQ HIAT09, 08/06/2009, Slide 15

16 ReA3 hardware tests at ArtemisB ReA3 stable source Artemis-B B ECR test-stand stand ECR R&D Beam dynamics R&D ReA3 R&D ReA3 multi-harmonic buncher HIAT09, 08/06/2009, Slide 16

17 LEBT hardware test Colutron source FFC MHB Allison Emit. Scan. solenoid x y 0 12 ns HIAT09, 08/06/2009, Slide 17

18 RFQ Beam simulations and electrode design completed (MSU) Mechanical design completed Procurement and construction started (Univ. Frankfurt) Injection energy: 12 kev/u Extraction energy: 600 kev/u Power (CW): ~150 kw HIAT09, 08/06/2009, Slide 18

19 RFQ parameters Charge to mass ratio, Q/A Max. Intervane voltage (kv) 86.2 Peak electric field (MV/m) 16.7 Peak field (E kilpatrick ) 1.6 Number of cells 94 Synchronous phase (degree) -20 Modulation factor Average radius (mm) 7.3 Tip radius (mm) 6.0 Focusing strength 4.9 cceptance ~ 0.8 π kev/u-ns exit of RFQ ε z (90%) ~0.29 π kev/u-ns HIAT09, 08/06/2009, Slide 19

20 ReA3 SRF cavities 3 cryomodules 15 cavities Type λ/4 λ/4 Optimum β Frequency E peak V acc E acc 80.5 MHz 80.5 MHz 16.5 MV/m 20.0 MV/m 0.46 MV 1.18 MV 4.84 MV/m 5.62 MV/m B peak mt 46.5 mt Temperature Length Aperture 4.5 K 4.5 K m 0.21 m 30 mm 30 mm HIAT09, 08/06/2009, Slide 20

21 ReA3 SRF linac beam energy ReA3 Deceleration ReA3 Acceleration FRIB acc. gradients Ep (MV/m) 16.5/ / /30.0 Q/A KE (MeV/u) KE (MeV/u) KE (MeV/u) HIAT09, 08/06/2009, Slide 21

22 Q/A=0.25 Beam phase spaces LINAC exit RFQ exit 4.6 MeV/u 3.0 MeV/u 0.6 MeV/u 0.3 MeV/u HIAT09, 08/06/2009, Slide 22

23 Beam distributions at experiment Q/A= MeV/u 3.0 MeV/u 0.3 MeV/u 2-4 mm 1-2 ns kev/u HIAT09, 08/06/2009, Slide 23

24 ReA3 SRF cavity prototypes ReA3 design goals exceeded β opt =0.041 β opt =0.085 Q Q β opt =0.041 ReA3 goal E p [MV/m] β opt =0.085 ReA3 goal 4.6 K 4.2 K E p [MV/m] HIAT09, 08/06/2009, Slide 24

25 β = QWR Prototypes 1st cavity Unstiffened No He vessel 2nd cavity Stiffened with He vessel HIAT09, 08/06/2009, Slide 25

26 b = QWR Prototypes Dewar Testing Q ReA3 FRIB Cavity 1st (4.6 K) 2nd (4.3 K) E p [MV/m] Both cavities exceed design goals HIAT09, 08/06/2009, Slide 26

27 Systems Tests Q Dewar 4.2 K Module 4.3 K E p [MV/m] β= QWR Performance in cryomodule is similar to Dewar performance HIAT09, 08/06/2009, Slide 27

28 Systems Tests Cold mass 77 K shield Vacuum vessel Rebuncher cryomodule for ReA3: assembly in progress HIAT09, 08/06/2009, Slide 28

29 Possible experimental layout Beam delivered to ReA3 experimental area by 2010 Instruments in preparation AT-TPC ANASEN Task Task leader: leader: A. A. Bickley Bickley AT-TPC ReA3 ReA12 HIAT09, 08/06/2009, Slide 29

30 Conclusion ReA3 is a new facility at the NSCL for stopped and reaccelerated radioactive beams coming in 2010 ReA3 will accelerate uranium beams to ~ 3 MeV/u ReA3 will initially use primary beams from the coupled cyclotron facility (<200 MeV/u 1 kw) ReA3 will then use primary beams from the FRIB driver linac (>200 MeV/u 400 kw) An upgrade ReA12 could accelerate uranium beams to ~ 12 MeV/u by adding three cryomodules HIAT09, 08/06/2009, Slide 30

31 Additional slides HIAT09, 08/06/2009, Slide 31

32 Beam rate estimate and beam properties Beam rates can be calculated from the NSCL website Beam rate estimates assumptions Predicted beam rates (LISE) Rate dependent stopping and extraction efficiency 1% for 10 8 /s, 5% for 10 7 /s, 20% for 10 6 /s Breeding efficiency: 60% Transport efficiency: 70% Delay time for decay losses: 100 ms (stopping + breeding) Expected beam properties Beam energies:» 238 U: MeV/u» 48 Ca: MeV/u Beams with variable duty cycle:»from μs macro-pulses to quasi-continuous beams Beam rate estimates have large uncertainties (one order of magnitude) HIAT09, 08/06/2009, Slide 32

33 High-current EBIT charge breeder Large trapping region (40 cm) High current up to 5 A High current density (>10 4 A/cm 2 ) Strong magnetic field: 6T Minimum Q/A = 0.2 Z charge state breeding q/a Mass range Efficiency time [ms] A < 40 > 60% 1-44 (H-Ti) fully stripped 2-40 ms or He like A ~ 100 > 50% (Nb-Re) Ne-like ms A ~ 200 > 40% (Lu-U) Ni-like ms HIAT09, 08/06/2009, Slide 33

34 Electrostatic devices Quadrupoles Modified from Frankfurt design Triple bender 75º + 15º HIAT09, 08/06/2009, Slide 34

35 ReA3 cryomodule components HIAT09, 08/06/2009, Slide 35

36 Prototype cryomodule assembly HIAT09, 08/06/2009, Slide 36

37 X-ray shielding HIAT09, 08/06/2009, Slide 37

38 Modern compact linac LEBT with multi-harmonic buncher Radio frequency quadrupole (RFQ) Superconducting RF linac HEBT with rebuncher ReA3 Platform view 12 kev/u 600 kev/u 238 U MeV/u 48 Ca MeV/u Energy range MeV/u for 238 U Higher energies for lighter ions Minimum energy spread 1keV Minimum pulse length 1 ns HIAT09, 08/06/2009, Slide 38

39 Diagnostics beam commissioning Diagnostics Station Devices 0 Faraday cup, attenuator, viewer 1 Faraday cup, attenuator, viewer, decay counter, MCP phosphor, emittance scanner 2 viewer 3 Faraday cup, movable slit, timing Diagnostics Station Devices 4 Faraday cup, movable slit, timing, 4-jaw slit, attenuator 5 Faraday cup, movable slit, timing, foil and Si det., defining aperture 6 Faraday cup, movable slit, timing, foil and Si det. 7 Faraday cup, movable slit, timing, foil and Si det. Station 5 Station 6 Station 7 Station 0 Station 1 Station 3 Station 4 Station 2 HIAT09, 08/06/2009, Slide 39

40 Beam diagnostic - example Beam profile monitors and timing detectors are adaptations from TRIUMF designs Faraday cup Beam profile monitor Foil & silicon detector Bunch length monitor HIAT09, 08/06/2009, Slide 40

41 FRIB Proposed cavity types C.K. Gelbke, 6/18/2009, Slide 41

42 FRIB Proposed cavities parameters C.K. Gelbke, 6/18/2009, Slide 42

43 Gas stoppers - example Linear Gas Cell works but has limitations Intensity-dependent extraction efficiencies Extraction time of ~100 ms Low stopping efficiencies for light beams Cyclotron Gas Stopper under development Shorter extraction times Higher beam rate capability G. Bollen, D.J. Morrissey, S. Schwarz, Nucl. Instr. Meth. A 550 (2005) 27 F. Marti et al., Cyclotrons-2007Conference proceedings HIAT09, 08/06/2009, Slide 43

44 Cyc-stopper Characteristics Weakly-focusing magnet and rf ion guiding techniques Ions injected using a solid degrader Slowed in a helium gas at low pressure (~ mbar) Longer path compare to linear gas stopper Ions extracted with static electric fields, rf carpet and ion guides Expected performance Fast extraction times ( ms) Beam rate limit > 10 8 p/s compatible with next generation facilities Capability to stop beams with 1.75 < A/Z < 3 and high efficiencies 100 MeV/u 78 Br 610 MeV after degradation HIAT09, 08/06/2009, Slide 44