1. NSCL Professor, SRF Department Manager Kenji Saito Status of FRIB: design plans, cavity and cryomodule development TTC Meeting November 5 2012 TTC meeting @ Jlab K. Saito, 5 Nov 2012, Slide 1

2. FRIB ASD, 19 June 2012, Slide 2 Outline  Overview FRIB and ReA Projects at MSU  Design Plans  Cavity and Cryomodule Development TTC meeting @ Jlab K. Saito, 5 Nov 2012, Slide 2

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4. TTC meeting @ Jlab K. Saito, 5 Nov 2012, Slide 4

5. SRF Lab (MSU funded) Layout FUTURE EXPERIMENTAL BUILDING 3 LARGE OAKS PRESERVED SRF Lab  Facility for FRIB mass-production  Future SRF world-leading research  MSU funded ~$ 25M  Complete by end of 2013 27,000 square-foot building TTC meeting @ Jlab K. Saito, 5 Nov 2012, Slide 5

6. FRIB Project Status  CD2/3A DOE Review succesfully took place on April 24-26 2012.  Began installation of pilings on 14 August 2012. TTC meeting @ Jlab K. Saito, 5 Nov 2012, Slide 6

7. , Slide 7 MSU ReA Project – Best R&D for FRIB  MSU-funded project  Re-accelerate rare isotope beam from FRIB  First SRF linac at MSU  Excellent test bench for FRIB QWRs  Operated at 4.5K, more stringent operation than FRIB In Operation Under fabrication 0.085 QWR CM 0.041 QWRs Rebuncher 0.041 QWRs SRF Department has full responsibility for the cryomodule construction ReA3 in 2013 ReA6 in 2014 TTC meeting @ Jlab K. Saito, 5 Nov 2012, Slide 7

8. FRIB ASD, 19 June 2012, Slide 8 FRIB: Three folded SRF LINACs 12 Needs 330 SRF Resonators and 49 modules TTC meeting @ Jlab K. Saito, 5 Nov 2012, Slide 8

9. 4 Resonators used in FRIB β = 0.041β = 0.085 β = 0.29 β = 0.53 typeβ0β0 f (MHz) V a (MV) a (mm) /4 0.04180.50.8134 /4 0.08580.51.7834 /2 0.293222.0940 /2 0.533223.740 TTC meeting @ Jlab K. Saito, 5 Nov 2012, Slide 9 00 0.0410.0850.290.53 f (MHz)80.5 322 V a (MV)0.811.82.13.7 E p (MV/m)3133 26 B p (mT)55706063 R/Q (Ω)402452224230 G (Ω)152278107 Aperture (mm)34 40 L eff ≡  (mm) 160320270503 Ea (MV/m)5.065.637.787.36 Bp/Ea =10.4 Ep/Ea =5.9 Bp/Ea =12.4 Ep/Ea =5.9 Bp/Ea =10.4 Ep/Ea =5.9 Bp/Ea =8.56 Ep/Ea =3.53 Ep/Ea and Bp/Ea are larger by a factor 2- 3 than  =1 electron cavity. FRIB Design

10. , Slide 10 FRIB Cold Masses Total 49 plus 4 spares β=0.53 QTY 18 + 1 matching β=0.29 QTY 12 + 2 matching β=0.085 QTY 11 + 2 matching (under design optimization) TTC meeting @ Jlab K. Saito, 5 Nov 2012, Slide10

11. FRIB 322 MHz β=0.53 Cryomodule Design Vacuum Vessel Resonator with Helium Vessel Alignment Rail Support Post μ-Metal Shield 1100-O Aluminum 38 K Shield 2 K Helium Relief Central Cryogenic Interface TTC meeting @ Jlab K. Saito, 5 Nov 2012, Slide 11

12. CM module components detail for ex.  =0.53 β=0.53 Cryomodule β=0.085 Cryomodule Cavity Fabrication Helium Vessel Fabrication Power CouplerThermal Shield Magnetic Shield Rail System Vacuum Vessel Cryogenics Tuner Solenoid Components are to be ordered vendors. Cavity final etching, certification test, coldmass assembly, cryomodule assembly are to be in-house. TTC meeting @ Jlab K. Saito, 5 Nov 2012, Slide 12

13. Number of Cryomodules Number of Cavities Number of Solenoids β = 0.041 Accelerating Cryomodules: 3 + 1 spare12 + 4 spare6 + 2 spare Matching Cryomodules: --- β = 0.085 Accelerating Cryomodules: 11 + 1 spare88 + 8 spare33 + 3 spare Matching Cryomodules: 2 + 1 spare6 + 3 spare0 β = 0.29 Accelerating Cryomodules: 127212 Matching Cryomodules: 2 + 1 spare4 + 2 spare0 β = 0.53 Accelerating Cryomodules: 1814418 Matching Cryomodules: 140 TOTAL49 + 4 spare330 + 17 spare69 + 5 spare SRF Cavities and Cryomodules for FRIB TTC meeting @ Jlab K. Saito, 5 Nov 2012, Slide 13

14. R&D Staus: ReA β=0.041 QWR Performance and Improvements for FRIB, Slide 14 Cold mass assembly Best results (naked cavity dunk test) A. Facco, April 2012 Lehman Review - B08 Dewar test results of ReA3 cavityies with helium jacket Buncher cavity tests 4.2K FRIB uses Hydrogen degassing (600 O C x 10hrs). Enough margin for ReA 4.5K performance FRIB chose 2K operation in order to increase gradient. 4.2K 2K FRIB BCP ReA FRIB uses BCP not EP.

15. Issue in β=0.085 QWR and Its Solution (a) Before elongation, regular plate (b) After elongation, regular plat (c) After degassing, regular plate (d) Directly Cooled 14 mm plate (e) Thin plate + titanium bottom flange (f) ReA6 Goal (4K) (g) ReA3 Goal (4K) Tuning plate simulated overheating  Poor thermal conductivity of NbTi bottom flange  Cooling of tuning plate is not sufficient due to superconductor (Nb)  Reduce H-field on the tuning plate  Elongate bottom tube,  Use Nb flange 4.2K ReA 0.085 4.2K TTC meeting @ Jlab K. Saito, 5 Nov 2012, Slide 15

16.  Applied to a QWR cavity Significant improvement in Qo at 4.2K Improvement, but more modest at 2K  The treatment will be applied to ReA QWRs working at 4.5 K  No benifit for FRIB, no baking in FRIB. Low Temperature Baking Effect 4.2 K – clear benefit 2 K – limited benefit After baking TTC meeting @ Jlab K. Saito, 5 Nov 2012, Slide 16

17. Refurbished ReA3 0.085 QWRs Extended bottom shape reduces the bottom flange heating. Changed to side coupler. TTC meeting @ Jlab K. Saito, 5 Nov 2012, Slide17

18. FRIB ASD, 19 June 2012, Slide 18 Puck and Tuner for ReA3Cavities Same tuning mechanism as 0.041 QWRs operating in ReA3 Improved tunability by puck: Variable Improved sensitivity by puck: ±3kHz/mm ±10kHz/mm Tuner Plate TTC meeting @ Jlab K. Saito, 5 Nov 2012, Slide 18 Welded Puck to increase tuner sensitivity

19. FRIB ASD, 19 June 2012, Slide 19 Frequency Tuning Procedure Established in the ReA3 Refurbish Cavities  Several tens of kHz spread in final frequency after construction require several intermediate frequency tests Top inner conductor weld contraction not completely predictable He vessel welding creates tensions and deformations Bulk etch Thermal treatment partially releasing stresses  New tuning procedure simplifies construction 1.Differential etching if needed (±100 kHz ), precision better than 10% 2.Adjustable tuning puck welded after cavity bulk etch and heat treatment (±30 kHz )  Relaxed frequency control tolerance by puck TTC meeting @ Jlab K. Saito, 5 Nov 2012, Slide 19 High H-field High E-field f=1/√LC Remove: C smaller, f higher “C” “L”

20. ReA3 Status and Frequency Tracking Revision 31 Oct 2012 L. Popielarski

21. FRIB Developed Quality Control by Particle Count SLS-1200 Liquid particle counter for HPR water drips

22. Cavity Performance of the Refurbished ReA3 b=0.085 QWR With Ti Jacket at 4.2K ReA 4.5K (FRIB 4.5K) X-ray TTC meeting @ Jlab K. Saito, 5 Nov 2012, Slide 22 ReA 4.5K Remind; Ep/Ea and Bp/Ea are larger by a factor 2- 3 than  =1 electron cavity.

23. FRIB ASD, 19 June 2012, Slide 23  Design modification with Refurbish cavities for ReA3 Extended bottom shape Side coupler  Develop adjustable side coupler handling 2kW  Coaxial cable capable 2kW MSU Side Coupler for ReA3 Refurbish Cavities ReA3, β=0.085 side coupler designed by J. Crips coupler Coaxial cable handling 2kW is very challenging. So far experienced 150W at TRIUMF TTC meeting @ Jlab K. Saito, 5 Nov 2012, Slide 23

24. FRIB ASD, 19 June 2012, Slide 24 FRIB 0.085 QWR FPC (ANL type) Warm Transition MYAT 201-021 Elbow Warm Window Vacuum Break Current ANL Coupler Current ANL Cold Window Proposed 77/38K intercept location TTC meeting @ Jlab K. Saito, 5 Nov 2012, Slide 24

25. FRIB ASD, 19 June 2012, Slide 25  Same tuner in  =0.041 and 0.085 QWRs  Mechanical link is transferred outside of cryomodule through concentric stainless steel tubes  Two removable remotely controlled actuators are installed in series: piezo actuator and linear drive stepper motor  External motors allow for maintenance and external tuner adjustments  In operation in ReA3 since 1 year  Under fabrication more 8 tuners for ReA3, Operation in next year  Imporved the tuner sensitivity with puck QWR Tuner Baseline Design A E D B C [A] Cavity vacuum connection, [B] Push- pull concentric tubes, [C] Bellows for cryostat interface, [D] piezo-electric actuator, [E] linear stepper drive TTC meeting @ Jlab K. Saito, 5 Nov 2012, Slide 25

26.  Status Prototypes from 2 different vendors reached FRIB specifications »V acc =3.7 MV, E p =31 MV/m, B p =77 mT Design problems detected in 1 st generation »High B p »He vessel Ti bellows not reliable »Cavity welding procedure to be improved Problems removed in the production HWR mechanical design 322 MHz, HWRs Prototypes Exceed FRIB Requirements in Naked Tests Prototype β=0.53 HWR HWR prototypes oo E p /E a B p /E a mT/(MV/m) R/Q Ohm G Ohm 0.533.58.4219101 TTC meeting @ Jlab K. Saito, 5 Nov 2012, Slide 26

27. Prototype HWR β=0.53 Performance HWR with helium vessel in the 2 K test insert 2 nd sound hot spot detection diagnostics tool TTC meeting @ Jlab K. Saito, 5 Nov 2012, Slide 28

28.  Cavity design upgraded from prototypes Average operation E a increased Peak magnetic and electric fields reduced: B p ≤ 70 mT and E p ≤ 35 MV/m to increase safety margin in operation for all cavities (SRF Review committee recommendation, demonstrated at TRIUMF) Cavity shunt impedance R sh increased to allow operation at higher gradient without exceeding the specified cryogenic load Mechanical design resembling the previous ones with larger diameter, sharing in most cavities the same tuners and couplers New cavities fitting the present cryostats (flange to flange distance unchanged) Cavity Baseline Performance Increased Due to Successful Development TTC meeting @ Jlab K. Saito, 5 Nov 2012, Slide 29

29. µ-metal global shield Superconducting cavity Superconducting solenoid TDCM (Technical Demonstration of Cryomodule) Grobal Magnetic Shilding 2 HWRs 0.053 One SC solenoid DOE Delivarables Cryomodule reaches liquid helium temperatures. Efficiency of mu-metal magnetic shielding is compared with predicted values. Cavities are continually locked to the FRIB LLRF control system. RF power on fundamental couplers is raised to full FRIB power. Ready for operation with all ancillary components. TTC meeting @ Jlab K. Saito, 5 Nov 2012, Slide 29

30.  He processing @ 2 K had no effect on improving the gradient in the available time  Multipacting limits the gradient to around 17 MV/m in E peak 2 K Dewar FRIB Spec 4 K Dewar Magnetized material effect ? Cavity Performance in TDCM TTC meeting @ Jlab K. Saito, 5 Nov 2012, Slide 30

31. , Slide 31 FRIB Baseline Schedule TTC meeting @ Jlab K. Saito, 5 Nov 2012, Slide 31

32. FRIB ASD, 19 June 2012, Slide 32  Changed to side coupler for FRIB 0.081 QWR  Need to improve design with respect to multipacting based on TDCM results  Bottom up assembly in FRIB cryomodules Status of FRIB SRF Modules β Cavity RF Design Cavity RF Performance FPC Design FPC Perfomance Tuner Design Tuner Performance Coldmass Assebly Module Assembly 0.041 ReA √√√√√√√√ 0.041 FRIB √Dec. 2012√Dec. 2015√ Same as ReA 0.041 QWR Bottom up assembly 0.085 ReA √√√√√ Same as ReA 0.041 QWR Apr. 2013 Similar to 0.041 QWR 0.085 FRIB √ Dec. 2012√June 2013√ Similar to 0.041 QWR Apr.2014 Aug. 2013 Bottom up assembly Dec. 2013 0.29 FRIB √Feb. 2013 Similar to 0.53 Same as 0.53 0.53 FRIB √ √ (old design) Dec. 2012 (N.D) √ (TDCM) √ (RT) (TDCM) √ Pneumatic tuner Nov. 2012 √ (TDCM) √ (TDCM) √ : Done, : Need to improve TTC meeting @ Jlab K. Saito, 5 Nov 2012, Slide 32