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Daniel adrien franco lespinasse - status of magnetron sputtered qwr

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The objective of this research is the deposition of a superconductive thin film onto copper Quarter Wave Resonator cavities that can be used in the HIE-ISOLDE facility at CERN. To do this, it was developed an innovative magnetron configuration source. Our experience has shown the efficiency of this particular configuration in order to deposit a uniform thin film, and also improve the superconductive properties of the niobium (Residual Resistance Ratio and Critical Temperature). This presentation presents the recent improvement of the niobium thin film properties and the procedure used to deposit and measure the first resonator at LNL of HIE-ISOLDE type.

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Daniel adrien franco lespinasse - status of magnetron sputtered qwr

  1. 1. ISTITUTO NAZIONALE DI FISICA NUCLEARE LABORATORIO NAZIONALE DI LEGNARO Laboratorio di Superconduttività STATUS AND DEVELOPMENTS OF SPUTTERED Nb/Cu QWRs AT LNL-INFN D. Franco Lespinasse, G. Keppel, S. Stark, A.A. Rossi, A.M. Porcellato, F. Stivanello, C.Pira and V. Palmieri THIN FILMS AND NEW IDEAS FOR SRF OCTOBER, 2014
  2. 2. Content Research framework Specific research aims Recent developments at LNL Conclusions and further works
  3. 3. Framework Cavities with accelerating field of 6 MV/m with a Q-value of at least 5X108
  4. 4. Our goal  Develop a magnetron sputtering configuration source to deposit QWRs for HIE-ISOLDE Copper substrates Nb/Cu QWR
  5. 5. Specific research aims  Develop a magnetron sputtering configuration source to deposit QWRs for HIE-ISOLDE Deposit a uniform thin film coating over the cavity. Improve the Tc and RRR values Deposit and measure the first resonator at LNL of HIE-ISOLDE type.
  6. 6. How to do that???? Magnetron sputtering  Main Advantage  Main Disadvantage High deposition rate Erosion of material not uniform
  7. 7. Magnetron sputtering vacuum system
  8. 8. Stainless steel cathode
  9. 9. Stainless steel dummy cavity
  10. 10. Magnetron sputtering depositions Stainless steel onto quartz samples Stainless steel onto copper strips
  11. 11. Stainless deposition Run Pressure (mbar) Power (Kw) Current (A) Voltage (V) Time (min) 1 8x10-3 3 8,1 370 30 2 8x10-3 6 14,5 415 30 3 2x10-2 6 19 320 30 4 5x10-2 6 20,5 290 30 5 2x10-2 6 20,5 280 60 6 8x10-3 10 23,1 453 45 7 8x10-3 10 15 450 60
  12. 12. Magnetic field confinement 6 5 4 3 2 1 0 -20 -15 -10 -5 0 5 10 15 20 Thickness (μm) Sample position
  13. 13. Stripping test t=0 After 3 hours
  14. 14. Niobium cathode
  15. 15. Niobium depositions Run Pressure Power Current Voltage Time Heating (mbar) (kW) (A) (V) (min) 200°C 1 1x10-2 3 10,2 280 25 NO 2 1x10-3 3 9,9 300 25 NO 3 1x10-2 3 10,8 270 35 NO 4 1x10-2 5 16,5 290 30 NO 5 1x10-2 10 33,2 300 30 NO 6 1x10-2 15 50,5 310 30 NO 7 1x10-2 15 49,8 305 30 YES 8 1x10-2 17 50,68 333 30 YES 9 1x10-2 17 50,6 337 30 YES 10 1x10-2 21 65,8 332 30 YES 11 1x10-2 25 74,8 340 30 YES I magnetic confinement II magnetic confinement III magnetic confinement IV magnetic confinement
  16. 16. Thickness results I magnetic confinement 1.4 1.2 1 0.8 0.6 0.4 0.2 0 Thickness (μm) -20 -10 0 10 20 30 Sample position
  17. 17. Thickness results II magnetic confinement 6 5 4 3 2 1 0 Thickness(μm) -20 -15 -10 -5 0 5 10 15 20 Sample position
  18. 18. Thickness results III magnetic confinement 6 5 4 3 2 1 0 Thickness (μm) -20 -15 -10 -5 0 5 10 15 20 Sample position
  19. 19. Thickness results IV magnetic confinement 6 5 4 3 2 1 0 -20 -15 -10 -5 0 5 10 15 20 Thickness (μm) Sample position
  20. 20. Magnetic field configurations A new configuration has developed in order to increase the thickness on the top of the cavity
  21. 21. Thickness results 4 3 2 1 0 Thickness (μm) -20 -15 -10 -5 0 5 10 15 20 Sample position 2±1μm
  22. 22. Superconductive properties Quartz sample  RRR and Tc measurements 푅푅푅 = 푅(300퐾) 푅(10퐾)
  23. 23. Superconductive properties  RRR and Tc measurements 70 60 50 40 30 20 10 0 0 10 20 30 40 RRR Power (kW) I configuration II configuration III configuration IV configuration
  24. 24. Superconductive properties  RRR and Tc measurements
  25. 25. Thin film morphology 500nm 400nmGJ Internal conductor External conductor
  26. 26. Deposition of Nb/Cu QWR  The sputtering process was carried out taking into account the following parameters:  Sputtering: Power 30 kW Voltage 408V Sputt. Pressure 6x10-3 mbar Current 72,57 A Time 40 min
  27. 27. Deposition of Nb/Cu QWR  An important parameter:  The cavity was heated at 450°C during the process
  28. 28. Deposition of Nb/Cu QWR QWR after surface treatment (SUBU) QWR after magnetron sputtering deposition
  29. 29. Cleaning and mounting High pressure rinsing 100 bar Cavity during the Nb/Cu plate mounting
  30. 30. Test cryostat
  31. 31. RF performance
  32. 32. First Magnetron Sputtered Nb/Cu QWR Isolde 0,0 5,0x105 1,0x106 1,5x106 2,0x106 109 108 107 106 18W @1,8K @4,2K Q E Acc [MV/m] 44W 105W
  33. 33. Conclusions and further works  The cavity has been deposited with a good homogeneity (2±1)  Superconductive properties (Tc and RRR) were improved with a new magnetron configuration source  The first cavity of HIE ISOLDE type has been deposited succesfully at Legnaro  A test cryostat has been built to measure the cavity performance  The RF performance is below the specification, however new depositions will be done.
  34. 34. Aknowledgements  Special thanks to:  W. Venturini Delsolaro Sergey Stark Anna M. Porcellato
  35. 35. Thanks for your attention

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