1. 08.12.20111S. Atieh EN-MME Manufacturing R&D for SPL β =1 cavities at CERN on behalf of the SPL cavities mechanical design and manufacturing team

2. EBW updates 08.12.20112S. Atieh EN-MME EB welding DESY & others: Vacuum: 5x10 -6 mbar Pumping time: ca. 20 min 2 Cryogenic - Pumps: ca. 2  10.000 l/s Iris welds (inside) equatorial welds (outside) DESY & others: Vacuum: 5x10 -6 mbar Pumping time: ca. 20 min 2 Cryogenic - Pumps: ca. 2  10.000 l/s Iris welds (inside) equatorial welds (outside) CERN late 80’s (50 m of EB welds for LEP Nb cavities) : Vacuum: 5x10 -5 mbar Pumping time: ca. 20 min Oil diffusion – Pump Special vacuum chamber Internal gun for equatorial welds CERN 2011 Vacuum: 5x10 -4 mbar Pumping time: ca. 20 min Oil diffusion – Pump Special vacuum chamber Internal gun for iris welds f(iris opening) External gun for equatorial welds CERN 2012 (8 m EB welds for 1 x β=1 SPL cavity): New EB welding machine 2012 at CERN Chamber (6x1.4x1.4 m 3 ), P down to 5.10 -6 mbar Electron beam generator with fast beam deflection (200 kHz) Electron-optical viewing system No internal gun (for SPL) but deflection system could be an alternative.

3. Working Pressure vs. RRR 08.12.20113S. Atieh EN-MME EB welding The RRR degradation can take place in the welding seam itself, but also in the HAZ (courtesy of W. Singer)

4. Cavity interfaces 08.12.20114S. Atieh EN-MME EB welding (courtesy of W. Singer) Niobium to titanium grade 5 (Ti6Al4V) EB welding successfully tested before and after heat treatment at 800 °C Formal qualification according to ISO 15614-11 is ongoing Mechanical testing at low temperature is ongoing

5. Nb / Ti V 08.12.20115S. Atieh EN-MME EB welding Before HTAfter HT UTS (MPa)152.7 ± 2.7158.8 ± 2.2 Elongation at break (%)24.8 ± 2.726.6 ± 0.1

6. Cavity interfaces 08.12.20116S. Atieh EN-MME EB welding (courtesy of W. Singer) Niobium to titanium grade 5 (Ti6Al4V) is not SPL nominal configuration Nb / SS 316 LN is requested Nb / SS 316 LN can not be joined done by fusion welding Iron rich compound (intermetallics)

7. Stainless steel interfaces 08.12.20117S. Atieh EN-MME Brazing (courtesy of W. Singer) Brazing Nb / SS 316 LN is a key technology Developed at CERN in the 1987. Difference in expansion of Nb/SS Nb tube fitted to SS flange Clearance ≤ 20 µm SS plug to expand the Nb Pure Cu filler metal Brazing temperature 1100°C, ∆ time << P< 10 -5 mbar

8. Stainless steel interfaces 08.12.20118S. Atieh EN-MME Brazing (courtesy of W. Singer) Ultrasonic examination Leak testThermal shock liquid N2 (x5)Ultrasonic examinationLeak testElectro-polishingHT ( 600°C/24h)Electro-polishingLeak testUltrasonic examinationThermal shock liquid N2 (x5)Ultrasonic examinationLeak testShear testLeak testUltrasonic examinationAssembly testMacroscopic examinationSEM assessment

9. Stainless steel interfaces 08.12.20119S. Atieh EN-MME EB welding INTERMETALLICS NumberHV 0.05 18390 19213 20242 21233 22266 23409 24469 42654 43532 44840 45964 46364 64216 65362 66289 67220 68856 69694 70326 71369 72128 73192

10. Cold gas dynamic spray 08.12.201110S. Atieh EN-MME Thought Solid- state coating deposition method a supersonic gas (N2) jet that propel fine coating powder particles ( 1-50 μm) at very high velocities (500-1200 m/s). Advantages: powders are not melted almost absence of oxidation during the process allows materials to be constructed layer upon layer Nb sheets ( t=1 mm,3 mm) with Cu cold spray OBZ GmbH/ Germany

11. Cold gas dynamic spray 08.12.201111S. Atieh EN-MME Thought Tubular Coating Tensile Test (TCT-Test) Micro Flat Tensile Test (MFT-test) Metallurgical characterization H ELMUT S CHMIDT U NIVERSITY University of the Federal Armed Forces Hamburg

12. ? 08.12.201112S. Atieh EN-MME Thought Cu substrate Nb coating

13. Menu for 2012 08.12.201113S. Atieh EN-MME Perspective Continue the actual program Weld characterization for Nb cavities: “weld distortion and shrinkage” Explore the new EB welding machine (Nb welds): filler metal, repair etc. Setup the fabrication of a Nb cavity Work on NDT: X-Ray tomography &…

14. Last slide 08.12.201114S. Atieh EN-MME Conclusion A.E. "If at first, the idea is not absurd, then there is no hope for it" Having a critical view to existing solutions “occasionally” could be advantageous. We learned during the fabrication of Cu cavity and will apply many things to the fabrication of Nb cavities. New EB welding machine in Feb. and we will start the machine qualification program for the Nb welds. 5 th Nb cavity will be fabricated at CERN in 2012. Key technologies identified and tests are ongoing (manufacturing backup)

15. 08.12.201115S. Atieh EN-MME Thank you for your attention ?

16. Industrial Cavity Fabrication (DESY) 08.12.201116S. Atieh EN-MME

17. Industrial Cavity Fabrication (DESY) 08.12.201117S. Atieh EN-MME

18. Industrial Cavity Fabrication (DESY) 08.12.201118S. Atieh EN-MME

19. Industrial Cavity Fabrication (DESY) 08.12.201119S. Atieh EN-MME

20. Working Pressure vs. RRR 08.12.201120S. Atieh EN-MME Backup W. Singer, 11th SRF Workshop, September 2003

21. Nb / Ti V 08.12.201121S. Atieh EN-MME Backup NbTi6Al4V ρ (Kg/m 3 )8600 – 8700 ( x 1.9)4410 – 4450 (/ 1.9) T m ( o C)2460 – 2470 (+830)1610 – 1660 (-830) K (W/m o C)54 – 57 (x 7.7)7.1 – 7.3 (/ 7.7)

22. New EBW machine 08.12.201122S. Atieh EN-MME Backup