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A RD 05: SURFACE PREPARATION STUDIES FOR SUPERCONDUCTIVE CAVITIES

A RD 05: SURFACE PREPARATION STUDIES FOR SUPERCONDUCTIVE CAVITIES. F. Eozénou, T. Saeki. PARTICIPANTS. OUTLINE. CONTEXT RESULTS ACHIEVED ON SINGLE-CELL CAVITY SURFACE ANALYSIS ON SAMPLES CONTINUED EXPERIMENTS. CONTEXT. MAIN ISSUE FOR ILC.

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A RD 05: SURFACE PREPARATION STUDIES FOR SUPERCONDUCTIVE CAVITIES

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  1. A RD 05: SURFACE PREPARATION STUDIES FOR SUPERCONDUCTIVE CAVITIES F. Eozénou, T. Saeki - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  2. PARTICIPANTS - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  3. OUTLINE • CONTEXT • RESULTS ACHIEVED ON SINGLE-CELL CAVITY • SURFACE ANALYSIS ON SAMPLES • CONTINUED EXPERIMENTS - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  4. CONTEXT - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  5. MAIN ISSUE FOR ILC • ILC is in the Technical Design Phase. • The goal of GDE S0 task is to achieve high gradient >35MV/m with yield >90% by the end of 2012 • Main reasons for gradient limitation: • Field emission • Early quench (thermal transition) → More R&D is necessary to overcome these issues = IMPROVEMENT OF THE SURFACE TREATMENT: Electro-Polishing (EP) and post EP treatments. - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  6. ELECTRO-POLISHING (EP) FACILITIES AT KEK (STF) AND SACLAY 9Cell EP set-up at KEK 1Cell EP set-up at Saclay + PROGRAM FOR VERTICAL EP FACILITY AT SACLAY - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  7. DESIGN OF A VERTICAL EP FACILITY AT SACLAY To be used in: - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  8. SET-UP AND PREPARATION AREA - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  9. VARIOUS ANALYSIS TOOLS AT KEK (XPS, Auger/AES, SIMS, Sputtering, etc..) Surface Analyses (XPS)elemental analysis（>He), chemical analysis Surface Analyses (Auger/AES)elemental analysis（>He) Surface Analyses (SIMS)elemental analysis（all) Surface Conditioning (Electron Irradiation, Sputtering, Heating) Electron Argon - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  10. RESULTS ACHIEVED WITHIN THE COLLABORATION SURFACE TRATMENTS ON 1-CELL CAVITY - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  11. CHEMICAL REACTIONS DURING EP: SULFUR IS GENERATED H2 - SO42- S Al 3+ H+ Nb5+ + - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  12. FIELD EMISSION IS STILL A MAJOR ISSUE Field Emission → Necessary to improve contaminants removal on cavities - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  13. SET-UP FOR SPONGE WIPING ON SINGLE-CELL UPW + detergent outlet Sponge mechanics Insertion PE sponge UPW + detergent inlet Poly-Ethylene (PE) sponge wipe handle Sponge Expansion and Wipe by rotation - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  14. SPONGE-WIPE TESTED ON « GOOD » CAVITY Does Sponge-Wipe induce Field-Emission? →Tested on 1DE1 which quenches without FE. - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  15. SPONGE-WIPE RECIPE AT KEK • Poly-Vinyl-Chloride (PVC) sponge was set to the sponge-wipe tool. (Poly-Ethylene sponge was used in the fitting test of sponge-wipe tool in 2008.) • Insertion of sponge-wipe tool into the cavity (D1DE1). • Filling FM-20 (5%) into the cavity. • Rotation of sponge-wipe tool (clockwise 20 times + anti-clockwise 20 times) x 2 === In the fitting test in 2008, we only performed clockwise rotation. Anti-clockwise rotation was applied for the first time and this caused a failure in this test. === • Draining FM-20 (5%) from the cavity • Running U.P.W. into the cavity and rotation of sponge-wipe tool (clockwise 20 times + anti-clockwise 20 times) x 2. • Draining U.P.W. from the cavity. • Removing the sponge-wipe tool from the cavity. • Running U.P.W. into the cavity in a Ultrasonic hot-water bath at 500C for 1 hour. • HPR for 1 hour. • Drying the cavity in the clean-room. - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  16. SPONGE-WIPE TOOL SCRATCHED THE IRIS Mistake occured during 1DE1 Sponge-Wipe Cleaning - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  17. DETERIORATION OF THE SURFACE Iris EBW seam. Scratched part. + Aluminum traces BP side Cell side - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  18. ORIGINS OF THE SCRATCH Screw joint was unscrewed during anti-clockwise rotation of sponge-wipe tool. After sponge-wipe process, we found that the lower part of sponge-wipe tool axis had been unscrewed and been disassembled inside the cavity during the wiping process. - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  19. What happened during the sponge-wipe process UPW + detergent outlet Sponge mechanics Insertion UPW + detergent inlet This iris part was scratched by the aluminum structure of sponge-wipe tool. wipe handle This end was free during the sponge-wipe process. Sponge Expansion and Wipe by rotation - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  20. SULFURIC ACID RINSING AS A CURE? Field Emission A part of the aluminum has been removed, but not sufficient to cure the cavity. → Local Grinding of the cavity (Cavity shipped to KEK). - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  21. LOCAL GRINDING AT KEK Head : Diamond seat Motor (3000 rpm) CCDcamera＋LED Scratches on iris After grinding Grinding machine - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  22. (PARTIAL) RECOVERY AFTER LOCAL GRINDING OF THE CAVITY Field Emission → Needs additional treatment for further improvement (EP?) → Cavity is sent back to KEK - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  23. ANALYSIS OF 1DE1 CAVITY Temperature-Mapping was done during Test. Feb. 2010 at Saclay T-map heating location = Equator marked position KEK Optical Inspection setup - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  24. INSPECTION OF THE HEATING ZONE AT KEK 9mm No suspicious deffect is found at the heating zone. → Additional EP at KEK for total performance recovery 12mm - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  25. STAIN PROBLEM AT STF/KEK AFTER EP Brown spot and traces are sometimes observed at KEK after Horizontal EP Typical stains observed after EP (Kyoto-camera inspection) picture examples using new LED illumination Problem with the rinsing protocol? Problem due to the fresh EP mixture? - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  26. ID number 1 STAINS PROBLEM ON 1DE1 downstream Iris ~270degree clear brown stain 1.3 mm faint brown stain cell side beam pipe side EBW seam - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  27. STAIN RECORD of 1DE1-cavity STAIN PROBLEM SOLVED! Stains are removed after refinement of the rinsing procedure. - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  28. SURFACE ANALYSIS ON SAMPLES - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  29. EFFECT OF POTENTIAL ON CONTAMINATION = Theoritical way to reduce Contamination? Reduction Reactions at the Cathode Reduction of H+: 2 H+ + 2 e-→ H2 (Predominant) Reduction of SO42-: SO42- + 8H+ + 6e- → S + 4H2O Does the cathodic overpotential provoked by a too high voltage an increased sulfur generation? Sample A, 20 Volts: 9.18g removed 51 hours EP Sample B, 5 Volts: 9.11g removed 115 hours EP Assumed sulfur contamination + additional undesirable reactions??? - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  30. XPS ANALYSIS AT SACLAY ON CONTAMINATED SAMPLE Additional parasitic reduction likely to happen in HF depleted EP mixture - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  31. KEK-SACLAY EXCHANGE PROGRAM ON SAMPLES • 4 samples electro-polished at Saclay and sent to KEK for surface analysis • High Voltage in Fresh EP Mixture • High Voltage in Aged EP Mixture • Low Voltage in Fresh EP Mixture • Low Voltage in Aged EP Mixture A dedicated transportation box has been designed at KEK to keep the sample under inert gas atmosphere - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  32. TRANSPORTATION BOX (KEK DESIGN) - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  33. XPS ANALYSIS AT KEK (1) - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  34. XPS ANALYSIS AT KEK (2) Numerous components are found at the sample surface - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  35. FIRST CONCLUSIONS Differences are observed between Saclay and KEK samples Sample analysis must be pursued for better understanding of the results - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  36. CONTINUED EXPERIMENTS - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  37. HISTORY OF 1DE1 SINGLE-CELL CAVITY CEA/Saclay KEK/STF Eacc=40MV/m in VT on 28 Oct. 2008 21 Jul. 2009 Failure of sponge-wipe on 12 Aug. 2009 HF rinse, H2SO4 rinse to remove Al at scratch. Eacc~25 MV/m limited by field-emission in VT on 14 Nov. 2009 17 Sept. 2009 3 Dec. 2009 Scratch was removed by Local-grinding + EP(50um) + HPR on 8 Jan. 2010 VT is scheduled on 17 Feb. 2010 Jan. 2010 - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  38. OUTLOOK FOR 1DE1 CAVITY Cavity exchange program will be pursued. (1) send it back to Saclay (2) confirm no FE by VT, sent back to KEK (3) sponge-wipe to prove no-harmful. (4) send it back to Saclay (5) confirm no effect by VT - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  39. COMPLEMENTARY TESTS WITH LOCAL GRINDING • C1-21 Cavity • Goal: Cavity limited by early hard quench (25MV/m). • Recovery after local grinding? • Test with T-mapping (Saclay) • Printing of the surface (Saclay) • Local grinding of the surface + EP (KEK): tbc • RF test (Saclay) - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  40. 1AC3 Cavity This cavity is a pristine one. It will be EP’ed in “undesirable” conditions to evaluate efficiency of sponge-cleaning recipe. Complementary EP (KEK) RF test (Saclay) EP with aged acid mixture and high voltage (Saclay) RF test (Saclay). F.E expected Sponge cleaning recipe (KEK) RF test (Saclay) NEW TEST WITH SPONGE-CLEANING - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

  41. Thank You for your Attention - F. Eozénou, T. Saeki - FJPPL 2010 A_RD_05

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