1. FNAL SRF Program: 1.3 GHz Camille M. Ginsburg (FNAL) Fermilab Accelerator Advisory Committee November 7-9, 2011

2. 1.3 GHz activity: Technical Progress R&D on cavity gradient (E acc ), quality factor (Q 0 ), and manufacturing yield  Cavity inspection, tests, diagnostics  Cavity production and R&D surface processing  L. Cooley Construction of cryomodules for ILC RF Unit test at New Muon Lab Operation of 1.3 GHz cryomodules in NML   M. Church  Cavity performance from vertical test to horizontal test to cryomodule test New US cavity vendor development Ginsburg, Accelerator Advisory Committee, Nov. 7-9, 2011 2

3. 1.3 GHz goals: FY12 and beyond Reduce cost, improve reliability and repeatability Achieve ILC gradient and Q 0 (E acc >35 MV/m, Q 0 >8E9)  for ILC R&D Increase gradient and Q 0 (E acc >45 MV/m, Q 0 >2E10)  for ILC 1TeV upgrade Maximize Q 0 at moderate gradients (15<E acc <20 MV/m)  for Project X Operate 1.3 GHz cryomodules in NML  Cavity performance from vertical test to horizontal test to cryomodule test Ginsburg, Accelerator Advisory Committee, Nov. 7-9, 2011 3

4. ILC 1.3 GHz SRF Cavities e - e + Ginsburg, Accelerator Advisory Committee, Nov. 7-9, 2011 4 ILC Reference Design Report, August 2007 http://www.linearcollider.org/cms/?pid=1000437 Two 11-km linacs, one for electrons and one for positrons accelerate from injected energy of 15 GeV to the final beam energy of 250 GeV ~16000 1.3 GHz superconducting RF cavities, based on TESLA design, operating at average gradient 31.5 MV/m Spec in vertical test: (E acc >35 MV/m, Q 0 >8E9)

5. Project X Linac SRF Cavities Ginsburg, Accelerator Advisory Committee, Nov. 7-9, 2011 5  =0.11  =0.22  =0.4  =0.61  =0.9 325 MHz 10-160 MeV  =1.0 1.3 GHz 3-8 GeV ILC 162.5 MHz 2.1-10 MeV 650 MHz 0.16-3 GeV SectionFreqEnergy (MeV)Cav/mag/CMType HWR (  G =0.11) 162.52.1-109 /6/1Half Wave, solenoid SSR1 (  G =0.22) 32510-4216/8/ 2Single Spoke, solenoid SSR2 (  G =0.47) 32542-16036/20/4Single Spoke, solenoid LB 650 (  G =0.61) 650160-46042 /14/75-cell elliptical, doublet HB 650 (  G =0.9) 650460-3000152/19/195-cell elliptical, doublet ILC 1.3 (  G =1.0) 13003000-8000224 /28 /289-cell elliptical, quad CW Pulsed 1.3 GHz program: Supplies 224 3-8 GeV section cavities Contributes to R&D, especially critical: 650 MHz  G =0.9 heat load H-H-

6. Cavity Performance Benchmark Ginsburg, Accelerator Advisory Committee, Nov. 7-9, 2011 6 International cavities from established vendors using established processes 2 nd pass yield for >35 MV/m for integrated sample is (61 +- 9)% for 2010-2011 alone is (82 +- 12)% International Workshop on Linear Colliders, Granada, Spain, September 29, 2011 Presented by K. Yokoya http://ilcagenda.linearcollider.org/getFile.py/access?contribId=18&sessionId=1&resId=0&mat erialId=slides&confId=5134 1 st pass 2 nd pass

7. 1.3 GHz Cavity Inventory Fermilab provides stewardship of ILC cavities for the Americas region  Strong collaboration with JLab and Cornell Ginsburg, Accelerator Advisory Committee, Nov. 7-9, 2011 7 # ordered90 # received50 # processed43 # vertically tested42 # dressed19 # horizontally tested14 # CM2 qualified8 Status 30.Sep.2011

8. 35 MV/m Ginsburg, Accelerator Advisory Committee, Nov. 7-9, 2011 8 Many cavities reach ILC gradient

9. More 9-cell Baseline Cavities in the Pipeline Ginsburg, Accelerator Advisory Committee, Nov. 7-9, 2011 9 In the upcoming weeks and months we will process and test  Three remaining from an AES batch of 6, received 10- 15 um BCP at AES  Four remaining from a Niowave-Roark batch of 6, received light BCP at NR In the longer term 40 ARRA cavities from AES, NR, and PAVAC are due CY2011-2012

10. New Cavity Vendor Development: AES Ginsburg, Accelerator Advisory Committee, Nov. 7-9, 2011 10 Denoted as an “established” vendor by ILC, by virtue of having passed ILC gradient after process/test with established process at JLab (many times, now) Sixteen 9-cell cavities received (4+6+6):  Four out of six in second batch achieved ILC spec in second pass

11. New Cavity Vendor Development: PAVAC Ginsburg, Accelerator Advisory Committee, Nov. 7-9, 2011 11 TE1PAV001 New facility in Batavia 1-cells: 6 fine-grain cavities fabricated, half with new ass’y technique “smart-”bells, half normal  Two “smart bell” cavities tested so far, std process  Both exhibited multipacting ~18-22 MV/m possibly due to unusual equator shape – under investigation 9-cells: 10 fine-grain cavities on order  Fabrication starts early CY2012

12. Six 1-cells tested extensively from 2008  24<E acc <29 MV/m in BCP/VT @Cornell, some had add’l prep/tests  Useful information learned, e.g., defect on die  Primarily being used for commissioning now Six 9-cells received 2010-2011  Two 9-cells tested, one in progress  TB9NR001@JLab: optical inspection shows many features, ~17 MV/m 1 st and 2 nd pass (quench); next may tumble at FNAL  TB9NR002@FNAL/ANL: optical inspection shows many features; reached 29 and 24 MV/m in 1 st and 2 nd passes (quench); considering cutting  QC shows fabrication not yet as stable as other vendors Ten more 9-cells in 2011: delivery complete soon New Cavity Vendor Development: Niowave-Roark Ginsburg, Accelerator Advisory Committee, Nov. 7-9, 2011 12

13. Two 1-cells received at Fermilab CY2010  Many features on the welds  Standard process (EP)/test  Achieved 19 and 21 MV/m with hard quench  Useful information learned, fed back into mfr process Two additional 1-cells received CY2011  One tested after standard process, then both tumbled  Both reached ILC specification Collaborator Cavity Development: RRCAT/IIFC Ginsburg, Accelerator Advisory Committee, Nov. 7-9, 2011 13

14. Vendor Surface Processing NR flash BCP’d the six 9-cells – insufficient data AES flash BCP’d latest batch of six 9-cell cavities – all show some pitting; three tested – related FE?  Is BCP the problem? Process not well controlled, e.g., acid flow too fast Pitting worse on lower surface than upper  Is material the problem? Pits re-emerge after tumbling R&D on sheet corners anticipated RI bulk EP’d half of the latest batch (six of twelve)  Performance likely to improve after heavier “light” EP So far, no performance advantage; potential advantage justifies controlled promotion  AES has a new EP machine Ginsburg, Accelerator Advisory Committee, Nov. 7-9, 2011 14

15. Cavities Flash BCP’d at Vendor TB9AES013: Pits observed in all three images, but generally enhanced by EP. Pits are not restricted to just the equator weld or the heat affected zone. 1) Optical inspection of equator weld before EP 2) Photo before electropolishing. 3) Photo after electropolishing ( ~ 120 microns removed) Ginsburg, Accelerator Advisory Committee, Nov. 7-9, 2011 15 1 2 3

16. Cavities Bulk-EP’d at Vendor Ginsburg, Accelerator Advisory Committee, Nov. 7-9, 2011 16 RI bulk-EP removal amount (um) 133 153 138 130 152 140 *KEK grinding repair * Status 30.Sept.2011

17. Low-field Q0 dependence on EP parameters Ginsburg, Accelerator Advisory Committee, Nov. 7-9, 2011 17 EP parameters varied during 2010 in response to ILC/S0 study (Saeki et al.) Start ( ): high voltage, high temperature [18V, 30-35°C @equator] After ILC/S0 study ( ): low volts, low temp [14.5V, 25-30°C] Final parameters (♦): high volts, low temp [18V, 25-30°C @equator] FNAL/ANL final EP recipe works well: some cavities reach ILC spec Process is stable and reproducible; key params monitored

18. Facility Throughput Ginsburg, Accelerator Advisory Committee, Nov. 7-9, 2011 18 Steady and improving throughput from ANL/FNAL processing, VTS, and HTS ANL/FNAL Processing CY2010: Surface process / test prep 44 electropolishing cycles 23 1-cell vertical test preps 32 9-cell vertical test preps CY2010: 81 vertical tests 38 9-cell, 39 1-cell, 4 R&D cavity tests VTS Status 30.Sept.2011 HTS

19. Cavity Dressing and CM Ass’y Twenty 1.3 GHz 9-cell cavities have been dressed at FNAL CM1 (ass’d from DESY kit) under test at FNAL Ginsburg, Accelerator Advisory Committee, Nov. 7-9, 2011 19 a dressed cavity cryomodule (CM1)

20. Cryomodule (CM2) Cavities Ginsburg, Accelerator Advisory Committee, Nov. 7-9, 2011 20 All CM2 cavities were processed and vertically tested at JLab, and dressed and horizontally tested at FNAL FNAL-CM2 23.Sep.2011 CM2 string (8-cavity + magnet) assembled and leak checked at FNAL Alignment, tuner tests ongoing Completion end CY11 FNAL-CM2 2.Nov.2011

21. 9-cell Cavity Repair/Process Development Ginsburg, Accelerator Advisory Committee, Nov. 7-9, 2011 21 FNAL/ANL EP process baseline for ILC cavities Tumbling (Centrifugal Barrel Polishing, CBP) Promising results for gradients and Q0 May make cavity performance less sensitive to manufacturing variations (not proven yet) Plan to develop as a new standard technique – fresh 9- cell cavities will go toward this effort Dressed EP technique developed  Proven on one cavity AES002 was improved by 50% (from 19.8 MV/m to 28.5 MV/m)  Three more cavities are candidates for improvement Laser re-melting under development Localized Grinding (led by KEK)  Two of three repaired cavities were tested, and both were substantially improved

22. 9-Cell Cavities: Tumbling Repairs Ginsburg, Accelerator Advisory Committee, Nov. 7-9, 2011 22 Break through ! Demonstrated cavity gradients > 35 MV/M Potential for drastic reductions in acid use. Demonstrated as a cavity repair method. Previously limited ~here TB9ACC015 Before CBP After CBP and 40 microns EP – Pit completely removed

23. Localized Grinding (by KEK) AES003 History  Four times tight-loop process/test at JLab, cavity consistently limited to average 19 MV/m Localized quench limitation T-mapped with JLab/FNAL collaboration  Various commissioning activities degraded cavity  Cavity sent to KEK for localized grinding Local grinding applied to limiting features and largest iris scratches EP 50 um, degreaser rinse, UPW rinse and HPR, surface inspection, HPR, sealed, pumped and then returned to FNAL  Without further FNAL/ANL processing, improved performance (FE limit)  After several additional process/tests, improved performance was maintained Struggled with field emission (probably not related to grinding), but eventually beat it TB9RI026 History  1 st test after standard FNAL/ANL EP: limited by FE Initially reached 28.8 MV/m with several FE burn-off events; did not recover well from one FE event; final gradient limit 19.6 MV/m  Iris pit was noted in FNAL optical inspection and molded  Cavity sent to KEK for localized grinding Local grinding of iris pit, tuning more than 98% flatness, and then 20-30um EP, followed by HPR, drying, and flanged in the clean room air  HPR and assembly at FNAL/ANL  Improved performance, field-emission free Ginsburg, Accelerator Advisory Committee, Nov. 7-9, 2011 23 Test after KEK local grinding TB9RI026 iris pit TB9RI026AES003 Tests before repair

24. Cryomodule CM1 Testing in Progress Ginsburg, Accelerator Advisory Committee, Nov. 7-9, 2011 24 Preliminary 7 cavities powered simultaneously. 8 th had tuner motor failure so powered alone Differences between DESY horizontal tests and FNAL CM1 tests under investigation

25. 1.3 GHz R&D Plans Process and test cavities to demonstrate required yield at 35 MV/M for ILC (~ same pace at FY11)  Cavity processing development Develop tumbling as a new standard process  Cavity diagnostics and repair  Follow cavity performance from vertical to horizontal to cryomodule test and feed back gained knowledge Cryomodule construction and test  CM2 assembly  Dress and HTS test cavities for CM3  CM1 post mortem and rebuild  S1 global cavity post mortem and rework Install CM2 at NML (1 st high gradient CM) and test ILC R&D directly benefits Project X pulsed linac, and indirectly other Project X cavity development Ginsburg, Accelerator Advisory Committee, Nov. 7-9, 2011 25