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S0 Status High-Gradient cavities

04Sep2008 EC meeting@KEK. S0 Status High-Gradient cavities. Lutz Lilje DESY. supplement by H. Hayano. Where are we?. America and Asia New vendors and new preparation setups Europe Previous production cycle Current production cycle Preliminary data. Reference;

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S0 Status High-Gradient cavities

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  1. 04Sep2008 EC meeting@KEK S0 Status High-Gradient cavities Lutz Lilje DESY supplement by H. Hayano Global Design Effort

  2. Where are we? • America and Asia • New vendors and new preparation setups • Europe • Previous production cycle • Current production cycle • Preliminary data Global Design Effort

  3. Reference; R. L. Geng et al., Proc. SRF2007, Beijing, WEP28 (2007). R. L. Geng et al., Proc. LINAC08, Victoria, Canada, in preparation. C. M. Ginsburg (FNAL), private communication. W. J. Ashmanskas and H. S. Padamsee, Proc. SRF2007, Beijing, WEP39 (2007).

  4. KEK 9 cell cavity status

  5. KEK Data: TESLA-Type KEK TESLA-shape cavities Global Design Effort

  6. LL #5 S0 Studies at JLab Ultrasonic Cleaning with degreaser much effective to reduce Field Emission

  7. DESY 4th: Field Emission Analysis Global Design Effort

  8. DESY 4th: Field Emission Analysis Z110 Optical Inspection done Z111 Global Design Effort

  9. Global Design Effort

  10. TESLA cavity Z110: #8 cell equator #8 equator, t=288 ~ 299 deg T-map data in test 2, 14.2 MV/m t=292 deg Quench location #8 equator 250 ~ 300 deg 10mm t=297 deg group of beads(?) with 10mm wide were observed. Similar beads group were also observed in several places. see following slides. 1mm

  11. TESLA cavity Z111: #6 cell equator #6 equator, t=193 ~ 204 deg T-map data in test 2, 16.0 MV/m t=198 deg 1.5mm Quench location #6 equator 175 ~ 225 deg t=199 deg group of beads(?) with 1.5mm wide were observed. 1mm

  12. Z110 summary 08/05/12 #9 Iris #8-#9i #8 #7-#8i cell equator #7 #6-#7i #6 #5-#6i #5 #4-#5i Group of spot #4 #3-#4i Scratch #3 Iris #2-#3i equator #2 #1-#2i T-map Heat spot #1 0 90 180 270 360 deg

  13. Z111 summary 08/05/15 #9 Iris #8-#9i #8 #7-#8i cell equator #7 #6-#7i #6 #5-#6i #5 #4-#5i Group of spot #4 #3-#4i Scratch #3 Iris #2-#3i equator #2 #1-#2i T-map Heat spot #1 0 90 180 270 360 deg

  14. DESY Current Production:Comparison of Final Treatment Preliminary Global Design Effort

  15. DESY 4th: Field Emission Analysis Global Design Effort

  16. DESY Current Production:Comparison of Final Treatment Preliminary Optical Inspection next Global Design Effort

  17. Camera Inspection Study of the STF TESLA-shape cavity #6 2008/3 : EBW parameter was decided by inspecting dumbbell EBW test samples. 2008/6 : STF TESLA-shape cavities #5 and #6 fabrication was completed. The first inspection by using Kyoto camera (After fabrication) 2008/7 : Pre-EP (5 um) and EP-1 (20 um), Total removed about 25 um. The second inspection by using Kyoto camera (After Pre-EP and EP-1) 2008/8 : 2nd EP-1 (100 um), Total removed about 25 um + 100 um The third inspection by using Kyoto camera (After EP-1) Five cat's eyes pits were found at equator, and Three cat's eyes pits were found at iris at STF TESLA-shape #6 cavity. *STF Baseline #5 cavity will be inspection from Sept. 15

  18. STF Baseline #6 cavity : #2 cell equator, Z=286mm, t=198 deg Measured line 1500 um 1mm

  19. Comparison with each treatment #2 cell equator, Z=286mm, t=198 deg 3 EP-1 (25 + 100 um removed) 1 2 After Fabrication EP-1 (25 um removed)

  20. STF Baseline #6 cavity : #6 cell equator, Z=746mm, t=283 deg Measured line 1500 um 1mm

  21. Comparison with each treatment #6 cell equator, Z=746mm, t=283 deg EP-1 (25 + 100 um removed) After Fabrication EP-1 (25 um removed)

  22. Where are we? • Production issues • Low-gradient cavities show defects found by temperature map and optical inspection • Training of manufacturers is mandatory • Preparation issues • Have less impact currently • Rinses developped within ILC R&D are successful • Ethanol (DESY), Ultrasound (JLab), Short EP (KEK) • Clear path forward • Apply high resolution inspection systematically to improve weld quality • Apply optimum surface preparation e.g. ethanol rinse Global Design Effort

  23. Inspection Camera Status KEK: 2 camera fabricated proto-type: under upgrading production-type #1: 1 year loan to DESY ( now at DESY ) ( 1 camera for US was proposed to US-JPN budget supplement, however it was not approved. ) production company contact was published to key players. JLab: LDM system ( Questar telescope + mirror system ) was developed.

  24. JLab LDM with T-map

  25. ACCEL8 (32MV/m) Equator2nd Cell from FPC JLab LDM Analysis ACCEL8 (32 MV/m) Equator4th Cell from FPC JLab/KEK/FNAL S0 meeting

  26. Guided Repair Development Status KEK: Local mechanical grinding Try to apply Ultrasonic tooling, micro-powder grinding, micro-powder buffing, to sample Nb plate. Insertion Mechanics is under design. JLab: Surface re-melting by EBW from outside. Try to apply re-melting to sample Nb plate with intentional pits.

  27. Rinse Development Status DESY: Ethanol Rinse JLab: Degreaser with ultrasonic KEK: Ethanol Rinse, Degreaser, H2O2 rise system are under developing. Sponge wipe is under evaluating by JLab collaboration. Mechanics is under design. preliminary sample test Sample#1 Sample#2 (sponge wipe applied) wipe test for sample in single-cell Significantly reduced Nb-O particles Lots of Nb-O particles (white)

  28. ILC S0 Feedback Loop Cavity Incoming QC Feedback: Improve Specification/QC Huge Irregularities eg. Scratches Standard Cavity Preparation Cycle Countermeasure (Guided Repair) Witness Samples Standard Vertical Test Cavity < XX MV/m Identify Irregularities eg. pits > XX MV/m Understand nature of high gradient limitation e.g. does minor EP move quench location Additonal Processing Cycle Standard Vertical Test Cavity Samples Single Cells Horizontal Tests or Module Assembly 4.4.2008 Lutz Lilje ILC Project@DESY Global Design Effort Global Design Effort 29

  29. Summary of S0 status 1. Cavity tests with optical inspection are come to standard procedure in KEK, JLab and DESY. 2. QC of EBW is recognized as important and inevitable. ( KEK has already started to instruct company. ) 3. Guided repair tools are under developing. 4. Rinse studies are under progressing. Global Design Effort

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