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           ...
Università degli Studi di Padova
          Istituto Nazionale di Fisica Nucleare
                   Cornell University



...
Università degli Studi di Padova
                  Istituto Nazionale di Fisica Nucleare
                            Corne...
Accelerating cavities
                                               Cavities



                                         ...
Quality factor Q
                                                 Cavities



                                            ...
Superconducting accelerating cavities
                                                   Cavities


  Niobium
            ...
Standard coating configuration
                                                                    Cavities

        Cooli...
Standard coating configuration
                                             Cavities
                Magnet
  Cylindrical
...
Q-slope for Nb/Cu cavities
                               Cavities



                              Standard
             ...
The CERN Result reproduced at INFN-LNL
                                          Cavities



                             ...
The CERN Result reproduced at INFN-LNL
                                          Cavities




    Qo= 2,5x109             ...
Ideas to improve the film quality:
                                         Cavities

  1. Increasing the sputtering rate ...
Ideas to improve the film quality:
                                                Cavities

  1. Increasing the sputterin...
Target shape
                                   Cavities



                                  Standard
                   ...
Target shape
                                   Cavities



                                  Standard
                   ...
Target shape
                                  Cavities



                                 Standard
                     ...
Target shape
                                    Cavities



                                   Standard
                 ...
Target shape modification
                                                                                                ...
Ideas to improve the film quality:
                                         Cavities

  1. Increasing the sputtering rate ...
Ideas to improve the film quality:    Cavities



                                     Standard
             0°           ...
The INFN-LNL hypothesis for the Q-slope




             Sputtering at different target-substrate angle

 Diploma thesis “...
The INFN-LNL hypothesis for the Q-slope




             Sputtering at different target-substrate angle

 Diploma thesis “...
At different target-substrate angle




                                                          110
                    ...
At different target-substrate angle
                                  Increasing level of
                                ...
At different target-substrate angle
                                   Increasing level of
                               ...
Ring Shaped Cathode
Ring Shaped Cathode
                                                Cavities



B // cathode                              ...
Ring Shaped Cathode
                       Cavities



                      Standard
                      technique


  ...
Ring Shaped Cathode
                                                 Cavities



                                         ...
Ring Shaped Cathode
                       Cavities



                      Standard
                      technique


  ...
Ring Shaped Cathode
                       Cavities



                      Standard
                      technique


  ...
Ring Shaped Cathode
                               Cavities



                              Standard
                    ...
Ring shaped cathode:lattice parameter
                                         Cavities



                               ...
Ring shaped cathode: thickness
                                  Cavities



                                 Standard
   ...
Ring shaped cathode: thickness
                                  Cavities



                                 Standard
   ...
Ring shaped cathode: RRR
                            Cavities



                           Standard
                     ...
Large Area Cavity Shaped Cathode
Bias Sputtering
                     Cavities


   Bias CERN
                    Standard
    Low ratio       technique

c...
Ideas to improve the film quality:
                                         Cavities

  1. Increasing the sputtering rate ...
Large area cavity shaped cathode
                                         Cavities


   The grid is behind the cathode    ...
Large area cavity shaped cathode
                                          Cavities


 The grid is behind the cathode     ...
Large area cavity shaped cathode
                                                              Cavities

                 ...
Large area cavity shaped cathode
                                    Cavities



                                   Standa...
Large area cavity shaped cathode
                                    Cavities



                                   Standa...
Large area cavity shaped cathode
                                      Cavities

                           Cathode
Biased...
Large area cavity shaped cathode
                                    Cavities



                                   Standa...
Large area cavity shaped cathode
                                      Cavities



                                     St...
Large area cavity shaped cathode
                                        Cavities



                                     ...
Bias Magnetron Sputtering
Ideas to improve the film quality:
                                                             Cavities

   1. Increasing...
Bias diode sputtering:
                                                                          Cavities



             ...
Bias Sputtering: Advantages
                                   Cavities



   Densification of the crystal   Standard
    ...
Bias Sputtering: Advantages
                                                   Cavities


  Increasing of the coating hard...
Bias Sputtering: Disadvantages
                                    Cavities


   Noble gas atoms embedding
               ...
Diode Bias Sputtering
                                            Cavities

   The positive bias applyed to the grid
 betw...
Diode Bias Sputtering
                                                 Cavities


      Combination of the CERN coating
  ...
Bias Magnetron Sputtering
                                         Cavities

                            Cathode
 Magnet  ...
BMS: the construction
                         Cavities



                        Standard
                        techni...
BMS: Results
                                                        Cavities



                                         ...
BMS: Pulsed Current Deposition
                                               Cavities


                          • Incre...
BMS: Pulsed Current Deposition
                                          Cavities


                      RRR values at   ...
BMS: texture
                Cavities



               Standard
               technique


                  New
        ...
BMS: Quartz substrates
                                             Cavities



                                          ...
BMS: Copper substrates
                                    Cavities


      Standard coating technique
                   ...
BMS: Copper substrates
                          Cavities



                         Standard
                         te...
BMS: Copper substrates
                                        Cavities


    Bias Magnetron coating technique
           ...
BMS: Copper substrates
                          Cavities



                         Standard
                         te...
BMS: Copper substrates
                          Cavities



                         Standard
                         te...
BMS: Copper substrates
                                                 Cavities



                                      ...
BMS: RRR                           Cavities



                                  Standard
                                ...
RF measures on 1,5 GHz cavities
                                    Cavities



                                   Standar...
RF measures on 1,5 GHz cavities
                                    Cavities



                                   Standar...
RF measures on 1,5 GHz cavities
                                    Cavities



                                   Standar...
RF measures on 1,5 GHz cavities
                                       Cavities

 Qo= 4,4x109
                            ...
RF measures on 1,5 GHz cavities
                                    Cavities



                                   Standar...
Summary

• Ring Shaped Cathode
   √ Results : RRR, Tc, lattice parameter
   √ Test with different magnets and coils
    co...
Summary

• Large Area Cavity Shaped Cathode
  √ cathode construction and several runs
  √ the structure stability was impr...
Summary

• Mixed Bias Magnetron Sputtering
  √   Results : RRR, Tc, lattice parameter
  √   Results : morphology and hardn...
THE END
Electrical properties
                            Nb on Cu
                             cavities

 RRR                    ...
Microstructural analysis: XRD
                                                                                            ...
Morphological analysis
                                                            Nb on Cu
                              ...
Cavity preparation
                                                        Nb on Cu
                                      ...
Electropolishing
                   Nb on Cu
                    cavities

                   Film and
                   ...
Electropolishing
                    Nb on Cu
                     cavities


Mixture:            Film and
               ...
Chemical polishing: SUBU
                           Nb on Cu
                            cavities

                       ...
Chemical polishing: SUBU
                           Nb on Cu
                            cavities
SUBU:
                  ...
HPWR
                                  Nb on Cu
                                   cavities

                             ...
Test RF su cavità 1,5 GHz
                            Nb on Cu
                             cavities

                    ...
Test RF su cavità 1,5 GHz
                            Nb on Cu
                             cavities

                    ...
Test RF su cavità 1,5 GHz
                                                         Nb on Cu
                              ...
Standard config.: SEM-AFM images
                                   Nb on Cu
                                    cavities
...
Morfology: AFM contact mode
                                           Nb on Cu
   Sputtering standard                    ...
Morfology: SEM-SE high resolution
                                           Nb on Cu
   Sputtering standard              ...
For this and many more thesis, visit the
        free download area on:




http://www.surfacetreatments.it/


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45 lanza ph_d_new magnetron configurations

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Il lavoro di questa tesi si propone di studiare il problema delle cavità di niobio su rame, partendo dalla caratterizzazione dettagliata dei film depositati per magnetron sputtering lungo una cavità 1,5GHz per finire studiando l’influenza che l’angolo di deposizione e la porosità hanno sulla degradazione delle proprietà superconduttive. Lo studio è stato condotto in maniera sistematica, effettuando numerose deposizioni su substrati di quarzo e rame, utilizzando i parametri di processo e la procedura standard
(CERN-INFN) per il ricoprimento di cavità 1,5GHz. Sono state utilizzate due diverse
configurazioni di magnetron e tutti i film ottenuti sono stati analizzati dal punto di vista delle proprietà superconduttive (temperatura critica, resistività e resistenza,), strutturali (diffrazione di raggi X) e morfologiche (microscopio a forza atomica). Lo studio ha comportato la deposizione di un numero elevato di campioni (13 serie per un totale di circa
140 substrati) e la messa a punto di tecniche di analisi.

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45 lanza ph_d_new magnetron configurations

  1. 1. For this and many more thesis, visit the free download area on: http://www.surfacetreatments.it/ http://www.slideshare.net/PalmieriProfEnzo
  2. 2. Università degli Studi di Padova Istituto Nazionale di Fisica Nucleare Cornell University NEW MAGNETRON CONFIGURATIONS FOR SPUTTERING Nb THIN FILMS INTO Cu TESLA- TYPE SUPERCONDUCTING CAVITIES Giulia Lanza
  3. 3. Università degli Studi di Padova Istituto Nazionale di Fisica Nucleare Cornell University PhD work Accelerating Standard New configurations Film and cavities technique cavity results Ring Large Biased shaped area grid cathode cathode Giulia Lanza
  4. 4. Accelerating cavities Cavities Standard technique New techniques Ring shaped cathode Multi-cell cavity excited in the  mode Large area cathode Biased grid
  5. 5. Quality factor Q Cavities Standard U G Q  2 f  technique Pd Rs New techniques Ring f = Resonance frequency shaped cathode Pd = Power dissipated on the cavity walls Large U = Total stored energy area cathode G = Geometrical factor Biased RS = Surface resistance grid
  6. 6. Superconducting accelerating cavities Cavities Niobium Standard • Low Surface technique resistance (2,5n a 1,7 K) New techniques Niobium on copper Ring shaped cathode • Low cost Large • High thermal stability area cathode Biased grid
  7. 7. Standard coating configuration Cavities Cooling water Ceramic break Standard Niobium technique cathode - 450 V New Vacuum techniques chamber Magnet Ring shaped cathode Glow discharge Sputtered niobium atoms Large area cathode Argon inlet Biased grid To the vacuum system
  8. 8. Standard coating configuration Cavities Magnet Cylindrical Standard magnetron technique Cavity New techniques Ring shaped cathode Large area cathode Niobium Biased cathode grid
  9. 9. Q-slope for Nb/Cu cavities Cavities Standard technique Nb New techniques Ring Nb/Cu shaped cathode Large area cathode Courtesy Cern Biased C. Benvenuti grid
  10. 10. The CERN Result reproduced at INFN-LNL Cavities Standard technique New techniques Ring shaped cathode Large area cathode Biased grid
  11. 11. The CERN Result reproduced at INFN-LNL Cavities Qo= 2,5x109 Standard technique New techniques Ring shaped cathode Large area cathode Qo= 2,7x108 Biased grid
  12. 12. Ideas to improve the film quality: Cavities 1. Increasing the sputtering rate R Standard technique New techniques Ring shaped cathode Large area cathode Biased grid
  13. 13. Ideas to improve the film quality: Cavities 1. Increasing the sputtering rate R Standard technique Ni i fi  Ni i  R New techniques i = Fraction of i = Impurities Ring impurities trapped sticking shaped into the film coefficient cathode Large Ni = Number of atoms area cathode impurities arriving on the film surface Biased grid
  14. 14. Target shape Cavities Standard technique New Plasma techniques Ring Target shaped cathode B Large area cathode 2 inches planar target Biased grid
  15. 15. Target shape Cavities Standard technique New Plasma techniques Ring Target shaped cathode B Large area cathode 2 inches planar target Biased grid
  16. 16. Target shape Cavities Standard technique New Plasma techniques Ring Target shaped cathode B Large area cathode 2 inches squared target Biased grid
  17. 17. Target shape Cavities Standard technique New Plasma techniques Ring Target shaped cathode B Large area cathode 2 inches rounded target Biased grid
  18. 18. Target shape modification Cavities -2 p = 2,5 * 10 mbar 3,5 Fit: I = a*V b Standard technique 3,0 Rounded target b = 9,0 New Squared target b = 8,3 2,5 techniques Increasing Current (A) 2,0 sputtering rate Planar target Ring 1,5 b = 6,9 shaped cathode 1,0 Large 0,5 area cathode 200 220 240 260 280 300 320 Cathode potential (v) Biased grid
  19. 19. Ideas to improve the film quality: Cavities 1. Increasing the sputtering rate R 2. Reducing the deposition angle Standard technique New techniques Ring shaped cathode Large area cathode Biased grid
  20. 20. Ideas to improve the film quality: Cavities Standard 0° technique New techniques Ring shaped cathode 45° Large area cathode Mechanical Matlab™ Biased simulation simulation grid
  21. 21. The INFN-LNL hypothesis for the Q-slope Sputtering at different target-substrate angle Diploma thesis “Morphology of Niobium Films Sputtered at Different Target-substrate Angles” Diego Tonini, LNL-INFN, Material Science, Padova University.
  22. 22. The INFN-LNL hypothesis for the Q-slope Sputtering at different target-substrate angle Diploma thesis “Morphology of Niobium Films Sputtered at Different Target-substrate Angles” Diego Tonini, LNL-INFN, Material Science, Padova University.
  23. 23. At different target-substrate angle 110 100 80 75 degrees relative intensity 60 60 degrees 40 200 211 45 degrees 220 310 222 321 20 30 degrees 15 degrees 0 20 40 60 80 100 120 140 2 Theta (degrees) AFM Roughness images XRD spectras
  24. 24. At different target-substrate angle Increasing level of contamination Superconducting properties
  25. 25. At different target-substrate angle Increasing level of contamination Electrical properties
  26. 26. Ring Shaped Cathode
  27. 27. Ring Shaped Cathode Cavities B // cathode Standard Cavity surface technique B New Cathode techniques Ring Magnet shaped cathode Large Higher area cathode deposition rate Biased grid
  28. 28. Ring Shaped Cathode Cavities Standard technique New techniques Ring shaped cathode Large area cathode Biased grid
  29. 29. Ring Shaped Cathode Cavities Standard technique New techniques Ring shaped cathode Large area cathode Biased Niobium ring to be leveled with the equator grid
  30. 30. Ring Shaped Cathode Cavities Standard technique New techniques Ring shaped cathode Large area cathode Biased Run 1 grid
  31. 31. Ring Shaped Cathode Cavities Standard technique New techniques Ring shaped cathode Large area cathode Biased Run 1 Run 2 grid
  32. 32. Ring Shaped Cathode Cavities Standard technique New techniques + Ring shaped cathode Large area cathode Biased Run 1 Run 2 Run 3 grid
  33. 33. Ring shaped cathode:lattice parameter Cavities Standard technique New techniques Ring shaped cathode Large area cathode 2 inches planar target Biased grid
  34. 34. Ring shaped cathode: thickness Cavities Standard technique New techniques Ring shaped cathode Large area cathode Biased grid
  35. 35. Ring shaped cathode: thickness Cavities Standard technique New techniques Ring shaped cathode Large area cathode Biased grid
  36. 36. Ring shaped cathode: RRR Cavities Standard technique New techniques Ring shaped cathode Large area cathode Biased grid
  37. 37. Large Area Cavity Shaped Cathode
  38. 38. Bias Sputtering Cavities Bias CERN Standard Low ratio technique cathode/substrate New area techniques Ring shaped cathode Low sputtering Large rate area cathode (1 micron /day) Biased grid
  39. 39. Ideas to improve the film quality: Cavities 1. Increasing the sputtering rate R 2. Reducing the deposition angle Standard technique 3. Increase the cathode/substrate area ratio New techniques Ring shaped cathode Large area cathode Biased grid
  40. 40. Large area cavity shaped cathode Cavities The grid is behind the cathode Standard technique New techniques - Ring Target shaped cathode Biased Grid + Large area cathode Substrate Biased grid
  41. 41. Large area cavity shaped cathode Cavities The grid is behind the cathode Standard technique New Advantages: techniques • Anode-cathode distance reduction Ring shaped • Higher cathodic area cathode Large • No shadowing due to the grid area cathode Biased grid
  42. 42. Large area cavity shaped cathode Cavities A B Standard technique Substrate Cathode BIAS New techniques Ring shaped Plasma is cathode conductive. Large The bias grid can area cathode be placed behind the cathode Biased grid
  43. 43. Large area cavity shaped cathode Cavities Standard technique New techniques Ring shaped cathode High ratio cathode/substrate area Large area cathode Biased grid
  44. 44. Large area cavity shaped cathode Cavities Standard technique New techniques Ring shaped cathode Large area cathode Biased grid
  45. 45. Large area cavity shaped cathode Cavities Cathode Biased -300 V Standard stainless technique steel tube New techniques Grounded Cavity Ring shaped cathode Large Insulator area cathode Biased grid
  46. 46. Large area cavity shaped cathode Cavities Standard technique New techniques Ring shaped cathode Large area cathode Biased grid
  47. 47. Large area cavity shaped cathode Cavities Standard technique New techniques Ring shaped cathode Large area cathode Vc = -300 V Biased p = 6x10-2mbar grid i = 5 A
  48. 48. Large area cavity shaped cathode Cavities Standard technique New techniques RRR = 4 Ring shaped cathode Large area cathode Vc = -300 V Biased p = 6x10-2mbar grid i = 5 A
  49. 49. Bias Magnetron Sputtering
  50. 50. Ideas to improve the film quality: Cavities 1. Increasing the sputtering rate R 2. Reducing the deposition angle Standard 3. Increase the cathode/substrate technique area ratio 4. Ion bombarment during film New techniques growing fi  N i i    Ring shaped Ni i     R cathode Large i = impurities sticking coefficient i = fraction of area Ni = atoms impurities arriving on the cathode impurities film trapped into β = function of the bias current due the film Biased to impurities ions grid R = sputtering rate
  51. 51. Bias diode sputtering: Cavities Standard technique New techniques Ring shaped cathode Large area Bias LNL cathode Up to now The bias technique is highly reliable: over 40 QWRs are installed and Biased working at LNL grid
  52. 52. Bias Sputtering: Advantages Cavities Densification of the crystal Standard technique structure New techniques Higher sputtering rate Ring shaped Lattice rearrangement cathode Large Films quality improvement area cathode Biased grid
  53. 53. Bias Sputtering: Advantages Cavities Increasing of the coating hardness Standard technique Similar defect annealing as does an New elevated substrate temperature techniques (E.Kay,G.Heim;J.Appl.Phys 49 (9) 4862 (1978)) Ring shaped Electrons bombardment reduction cathode Large area Adhesion improvement cathode Biased grid
  54. 54. Bias Sputtering: Disadvantages Cavities Noble gas atoms embedding Standard technique Lattice defects New techniques Thickness reduction Ring shaped cathode Biased grid shadowing Large area Still hydrogen removal is low cathode Biased grid
  55. 55. Diode Bias Sputtering Cavities The positive bias applyed to the grid between target and substrates promotes Standard technique the IONIC BOMBARDMENT OF THE GROWING FILM New techniques - Ring Target shaped cathode Biased Grid + Large area cathode Substrate Biased grid
  56. 56. Diode Bias Sputtering Cavities Combination of the CERN coating Standard configuration and the bias sputtering technique technique made from INFN-LNL New techniques Magnets S N S - Ring N S N Target shaped cathode Biased Grid + Large area cathode Substrate Biased grid
  57. 57. Bias Magnetron Sputtering Cavities Cathode Magnet - 250 V Standard technique New Grounded techniques Biased Cavity Grid Ring shaped +200 V cathode Large area cathode Biased grid
  58. 58. BMS: the construction Cavities Standard technique New techniques Ring shaped cathode Large area cathode Biased grid
  59. 59. BMS: Results Cavities Standard technique Biased magnetron sputtering New techniques Pulsed Quartz Copper Standard current substrates substrates and bias deposition technique Ring comparison shaped cathode Large area cathode Biased grid
  60. 60. BMS: Pulsed Current Deposition Cavities • Increases the Standard plasma density technique • Prevents the formation of arcs during the New deposition techniques Ring shaped cathode • Freq = 50 KHz, • T = 0.02 ms, Large area • ton = 0.01 ms cathode • reverse voltage = 10% Biased grid
  61. 61. BMS: Pulsed Current Deposition Cavities RRR values at Standard the equator technique positions are low New RRR<20 techniques Ring shaped cathode Q 0 ~ 107 a thin layer of Large area the cavity was cathode superconducting Biased grid
  62. 62. BMS: texture Cavities Standard technique New techniques Ring shaped cathode Large area cathode Biased grid
  63. 63. BMS: Quartz substrates Cavities Standard technique RRR of films New techniques with the same thickness don’t differ more that Ring the error bars shaped cathode Large area cathode Biased grid
  64. 64. BMS: Copper substrates Cavities Standard coating technique Standard technique New techniques Ring shaped cathode Large area cathode Biased grid
  65. 65. BMS: Copper substrates Cavities Standard technique New techniques Ring shaped cathode Large area cathode Biased grid
  66. 66. BMS: Copper substrates Cavities Bias Magnetron coating technique Standard technique New techniques Ring shaped cathode Large area cathode Biased grid
  67. 67. BMS: Copper substrates Cavities Standard technique New techniques Ring shaped cathode Large area cathode Biased grid
  68. 68. BMS: Copper substrates Cavities Standard technique New techniques Ring shaped cathode Large area cathode Biased grid
  69. 69. BMS: Copper substrates Cavities Standard biased niobium films technique had higher film hardness New techniques Biased Unbiased Ring shaped cathode biased niobium films had higher surface Large roughness area cathode Biased grid
  70. 70. BMS: RRR Cavities Standard technique New techniques Ring shaped cathode Large area cathode Tc always higher than Tcbulk Biased grid
  71. 71. RF measures on 1,5 GHz cavities Cavities Standard technique Biased LNL New techniques Ring Unbiased LNL shaped cathode Large area cathode Biased grid
  72. 72. RF measures on 1,5 GHz cavities Cavities Standard technique Bias LNL New techniques Ring Unbias LNL shaped cathode Large area cathode Biased grid
  73. 73. RF measures on 1,5 GHz cavities Cavities Standard technique Bias LNL New techniques Ring Unbias LNL shaped cathode Large area cathode Biased grid
  74. 74. RF measures on 1,5 GHz cavities Cavities Qo= 4,4x109 Standard technique Bias LNL New techniques Ring Unbias LNL shaped cathode Qo= 2,05x109 Large area cathode Biased grid
  75. 75. RF measures on 1,5 GHz cavities Cavities Standard technique Qo= 6,1x108 New techniques Ring shaped cathode Qo= 2,7x108 Large area cathode Biased grid
  76. 76. Summary • Ring Shaped Cathode √ Results : RRR, Tc, lattice parameter √ Test with different magnets and coils configuration √ Film thickness on the cavity cell is more uniform o Improve the cathode structure and the niobium quality o this configuration could be coupled with the bias magnetron
  77. 77. Summary • Large Area Cavity Shaped Cathode √ cathode construction and several runs √ the structure stability was improved √ poor results on coated films o film morophology studies o The number of cloves or their size should be reduced
  78. 78. Summary • Mixed Bias Magnetron Sputtering √ Results : RRR, Tc, lattice parameter √ Results : morphology and hardness √ Rf test on one cavity √ Different coating parameter tested o test with different boas voltage o several rf test on cavities o construction of a shaped grid
  79. 79. THE END
  80. 80. Electrical properties Nb on Cu cavities RRR Film and cavity R(300 K ) analysis RRR  R(10 K ) Standard technique Ring Tc ± Tc shaped cathode T(90%)  T(10%) Tc  Large 2 area T(90%)  T(10%) cathode TC  2 Biased grid
  81. 81. Microstructural analysis: XRD Nb on Cu cavities 2500 (211) Film and 2000 (110) cavity analysis 1500 Intensity Standard 1000 (310) technique (200) (222) Ring 500 (220) (321) shaped 0 30 50 70 90 110 130 cathode 2 Large area h2  k 2  l 2 2d ( hkl ) sin   n cathode Parametro reticolare: a 2 d hkl Biased =1.5418 Å grid
  82. 82. Morphological analysis Nb on Cu cavities Film and • AFM cavity analysis • SEM Standard • FIB-TEM technique • Microindentazione Ring shaped • Nanoindentazione cathode Large area cathode In collaborazione con Laboratorio Interdipartimentale di Microscopia Elettronica (LIME), Università “Roma3” Biased grid
  83. 83. Cavity preparation Nb on Cu cavities Film and cavity analysis Standard technique Ring shaped cathode Large area cathode Elettropolishig and Chemical Etching are fundamental Biased steps for the cavity internal surface treatment grid
  84. 84. Electropolishing Nb on Cu cavities Film and cavity analysis Standard technique Ring shaped cathode Large area cathode Biased grid
  85. 85. Electropolishing Nb on Cu cavities Mixture: Film and cavity analysis • Phosphoric acid • Buthanol Standard technique ratio 3:2 Ring shaped cathode Large area cathode Biased grid
  86. 86. Chemical polishing: SUBU Nb on Cu cavities Film and cavity analysis Standard technique Ring shaped cathode Large area cathode Biased grid
  87. 87. Chemical polishing: SUBU Nb on Cu cavities SUBU: Film and sulfamic acid cavity analysis hydrogen peroxide n-butanol Standard technique ammonium citrate Ring shaped PASSIVATION: cathode sulfamic acid Large area cathode Biased grid
  88. 88. HPWR Nb on Cu cavities Film and cavity analysis Standard technique Ring shaped While the cap is rotating, a cathode mechanism moves the bar along a vertical path to allow the Large water jets to scan the entire area cathode cavity’s surface. Biased grid
  89. 89. Test RF su cavità 1,5 GHz Nb on Cu cavities Film and cavity analysis Standard technique Ring shaped cathode Large area cathode Biased grid
  90. 90. Test RF su cavità 1,5 GHz Nb on Cu cavities Film and cavity analysis Standard technique Ring shaped cathode Large area cathode Biased grid
  91. 91. Test RF su cavità 1,5 GHz Nb on Cu cavities Film and cavity analysis Standard technique Ring shaped cathode Large area cathode After four etchings (chemical and electrochemical treatments) the results indicated poor characteristics Biased surface grid
  92. 92. Standard config.: SEM-AFM images Nb on Cu cavities Film and cavity analysis Standard technique Ring shaped cathode Large area cathode Biased grid
  93. 93. Morfology: AFM contact mode Nb on Cu Sputtering standard cavities Film and cavity analysis B Standard technique Sputtering Bias Ring shaped cathode Large area cathode Biased grid
  94. 94. Morfology: SEM-SE high resolution Nb on Cu Sputtering standard cavities Film and cavity analysis B Standard Sputtering Bias technique Ring shaped cathode Large area cathode Biased grid
  95. 95. For this and many more thesis, visit the free download area on: http://www.surfacetreatments.it/ http://www.slideshare.net/PalmieriProfEnzo

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