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

S0 Status Lutz Lilje DESY 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

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).

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KEK 9 cell cavity status TESLA shapeLL shape BL#1 in module 20.8MV/m, Q=1.8x10 10 MHI I9#1(LL#0) no coupler 29.3MV/m, Q=1.0x10 10 Kuroki BL#2 in module 29.4MV/m, Q=2.0x10 10 MHI I9#2(LL#1) module tested 19.0MV/m, Q=0.4x10 10 Kuroki BL#3 in module 20.5MV/m, Q=1.5x10 10 MHI I9#3(LL#2) 12.4MV/m, Q=1.2x10 10 Kuroki BL#4 in module 20.2MV/m, Q=2.0x10 10 MHI I9#4(LL#3) for tuner test --- Kuroki BL#5 under EP process --- MHI I9#5 no coupler, KEK, JLab tested 22.0MV/m, Q=2.0x10 10 (at KEK) 35.0MV/m, Q=0.8x10 10 (at JLab) Kuroki BL#6 under EP process --- MHI I9#6(PAL) no coupler, now in PAL --- Korea BL#7 under contract ---I9#7 new Ichiro 14.0MV/m, Q=0.7x10 10 Kuroki BL#8 under contract ---I9#8 new Ichiro --- Kuroki BL#9 under contract ---I9#9 new Ichiro under plan ---

S0 Status Lutz Lilje DESY Global Design Effort 6 KEK Data: TESLA-Type KEK TESLA-shape cavities

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

S0 Status Lutz Lilje DESY Global Design Effort 8 DESY 4th: Field Emission Analysis

S0 Status Lutz Lilje DESY Global Design Effort 9 DESY 4th: Field Emission Analysis Optical Inspection done Z110 Z111

S0 Status Lutz Lilje DESY Global Design Effort 10

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

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

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

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

S0 Status Lutz Lilje DESY Global Design Effort 15 DESY Current Production: Comparison of Final Treatment

S0 Status Lutz Lilje DESY Global Design Effort 16 DESY 4th: Field Emission Analysis

S0 Status Lutz Lilje DESY Global Design Effort 17 DESY Current Production: Comparison of Final Treatment Optical Inspection next

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 : 2 nd EP-1 (100 um), Total removed about 25 um 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

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

EP-1 ( um removed) After FabricationEP-1 (25 um removed) Comparison with each treatment #2 cell equator, Z=286mm, t=198 deg 12 3

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

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

S0 Status Lutz Lilje DESY Global Design Effort 23 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

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.

JLab LDM with T-map

JLab LDM Analysis 5/1/08, Rongli Geng JLab/KEK/FNAL S0 meeting ACCEL8 (32 MV/m) Equator 4 th Cell from FPC ACCEL8 (32MV/m) Equator 2 nd Cell from FPC

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.

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

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

S0 Status H. Hayano Global Design Effort 30 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.