Prsentation PowerPoint

May 28th 20121

A RD 05:SURFACE PREPARATION STUDIESFOR SUPERCONDUCTIVE CAVITIES

F. Eoznou, T. Saeki- F. Eozenou / T. Saeki - A_RD_05CEA DSM IrfuCEA DSM Irfu

May 28th 2012 - F. Eozenou / T. Saeki - A_RD_052CONTEXT

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May 28th 2012- F. Eozenou / T. Saeki - A_RD_053MembersIrfuKEKLeader: Eoznou FabienLeader: Takayuki SaekiVisentin BernardHitoshi HayanoBerry StphaneKen WatanabeAntoine ClaireShigeki KatoMasashi YamanakaMotoaki SawabePARTICIPANTS

Visit Saeki San & Yamanaka San @ Saclay in March 2012CEA DSM Irfu

May 28th 2012- F. Eozenou / T. Saeki - A_RD_054SURFACE TREATMENTS FOR LARGE SCALE CAVITY PRODUCTIONInternational Linear Collider~16000 Superconductive Niobium cavities > 31.5 MV/m

Improvement of the preparation of the SC Nb cavitiesCleaning of the surfaceReparation of defectsIncrease in the reprocubility of the processCost reductionIndustrialization

Cavity tratment/exchange programSample treatments/analysis

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May 28th 2012- F. Eozenou / T. Saeki - A_RD_055EXAMPLES OF CONTRIBUTION WITHIN TYL

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May 28th 2012- F. Eozenou / T. Saeki - A_RD_056LOCAL GRINDING AT KEK

CCD cameraLEDHead : Diamond seat Motor (3000 rpm)Grinding machine

Scratches on iris After grinding

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6May 28th 2012- F. Eozenou / T. Saeki - A_RD_057

Recovery of the cavity after local grinding of the defects at iris.grindingIMPROVEMENT AFTER GRINDING OF DAMAGED CAVITY

RF test of damaged 1CellTest after grinding and EPCEA DSM Irfu

May 28th 2012- F. Eozenou / T. Saeki - A_RD_058

Poly-Ethylene (PE) spongewipe handleSponge mechanicsInsertionSponge ExpansionandWipe by rotationUPW + detergent inletUPW + detergent outlet

PE spongeSET-UP FOR SPONGE WIPING ON SINGLE-CELL

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8May 28th 2012- F. Eozenou / T. Saeki - A_RD_059RESULTS ACHIEVED WITH SINGLE-CELLTest with a good cavity (Eacc>35 MV/m, no FE)Sponge wipe at KEKVT at SaclayThe performance of the cavity is maintainedThe process do not deteriorate performance

Tests in challenging conditions (FE limited cavity)No improvement achievedBut suspicious cleaning sequenceExperiment will be repeated

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May 28th 2012- F. Eozenou / T. Saeki - A_RD_0510Field flatness degradation experimentally observed at KEK after electropolishing,How can modelling help us understand (and solve) the problem?

Fluid velocity[HF] at 4 000 s[HF] at 20 000 s Good electropolishing of central cell #5

Electro-polishing will depend on the cell location for others

Electropolishing needs to be improved in the other cells

HFmol/m3Velocity m/sTESLA CavitiesMODELLING OF ELECTRO-POLISHING (Saclay)

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May 28th 2012- F. Eozenou / T. Saeki - A_RD_0511SURFACE CONTAMINATION ANALYSIS OF SAMPLESSamples EPed at KEK & SaclayAnalysis at KEKSame contaminants found (S, F, C)More sulfur @ KEKInfluence of anode-cathode distance?

Experiments to be continued

Surface Analyses (XPS)Surface Analyses (Auger/AES)Surface Analyses (SIMS)

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May 28th 2012- F. Eozenou / T. Saeki - A_RD_0512NEW EQUIPMENTS, NEW CHALLENGES

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May 28th 2012- F. Eozenou / T. Saeki - A_RD_0513VERTICAL EP (VEP) AT CEA SACLAY

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May 28th 2012- F. Eozenou / T. Saeki - A_RD_0514

3 cm

EVOLUTION OF EP @ CEA SACLAY2004: Experiments on flat samples:2006: Operation of 1Cell Horizontal EP set-up2011: Operation of Vertical EP Set-up

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May 28th 2012- F. Eozenou / T. Saeki - A_RD_0515

September 2011: Commissioning, Tests with waterOctober 2011: Connections to exhausts, tests with acid in novemberJanuary 2012: Area closed. Final configuration.EVOLUTION OF THE VEP SET-UP

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- F. Eozenou / T. Saeki - A_RD_0516

HORIZONTAL VS VERTICALPros:Good evacuation of gases (cavity half filled)Demonstrated efficiencyLarge range of parametersCons:Complicated processRotary sealsSwitching of the cavityLow removal ratePros:Simple processLow floor surfaceImproved safetyHigher removal rateCons:Sensitive to fluid dynamicsProper parameters to be determinedVoltage and fluid velocityMay 28th 2012

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rZ

VERTICAL CONFIGURATION AND MODELLINGCathodeFzConfiguration simpler in VEP case:Symmetry according to z-axis

2D axisymmetry model

Fluid velocity[HF] at 4 000 s[HF] at 20 000 s Modelling of horizontal EP:Difficult: no symmetryHints for non uniform polishing- F. Eozenou / T. Saeki - A_RD_05May 28th 2012

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Gravit est invariant en rotation autour de laxe z15 volts appuy entre la cavit et la cathode

1718EXAMPLE OF MODELLING

Modelling (COMSOL) with rod cathodeArea close to the cell poorly swept with SPL cavitiesNeeds improvement

Electrolyte velocity: m/sFlow profile from the cathode to the cavity:Fluid velocity m/s Vs xFluid velocity m/s - F. Eozenou / T. Saeki - A_RD_05May 28th 2012

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19Modified Cathode Shape (SPL cavity)VEP WITH CIRCULATING ACID SHOULD NOT BE CELL DEPENDENTSHAPED CATHODE MAKE IT POSSIBLE TO IMPROVE THE FLOW

Example of fluid modelling with alternative shapeFluid velocity m/sFluid velocity m/s Vs xFluid velocity m/s - F. Eozenou / T. Saeki - A_RD_05May 28th 2012

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20

Parameters for 1st VEP sequence:

- 3 hours VEP- Shaped and masked cathode- 8 L/min acid flowrate, Nitrogen blowing- 20 V- Temperature < 26C

FIRST VEP WITH 1CellBenefits from VEP: operator friendly!

No flaw observed during the first VEP sequenceEasy preparation of the cavity (time saved + security)More efficient rinsing procedures Very stable process Adapted to industry - F. Eozenou / T. Saeki - A_RD_05May 28th 2012

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Bright SurfaceBrighter on top half-cell but bubble traces

20 V = Oxygen generationRESULTS AFTER EPV A 20VAcid flow (8L/min) not sufficient to stir the gas- F. Eozenou / T. Saeki - A_RD_05

+Ar Baking 3hx145CMay 28th 2012

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22EPV WITH LOWER VOLTAGE (12V)

No obvious bubble trace at the upper cellBrightening of the surfacePromising Voltage

Waiting for the RF Test of the cavity- F. Eozenou / T. Saeki - A_RD_05May 28th 2012

1Cell Vertically EPed at 12V. Improvement of the surface.CEA DSM Irfu

- F. Eozenou / T. Saeki - A_RD_0523NEW CAVITY FABRICATION FACILITY AT KEKMay 28th 2012

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Introduction of KEK activitiesThe fabrication-cost reduction of superconducting cavity is not enough for future project like ILC. We have constructed a new superconducting Cavity Fabrication Facility (CFF) at KEK for the study of cost-effective mass-production of cavity.All the necessary equipment for the cavity fabrication were installed in the CFF at KEK.We have fabricated 9-cell cavity KEK-00 (without HOM) in CFF. The fabrication process of KEK-00 and the vertical test result of KEK-00 will be shown.Future plan of CFF will shown as well as the plan of FJPPL collaboration between Saclay and KEK.2425Main Equipments of Cavity Fabrication FacilityInspection equipment for Nb surfaceEBW room Installation of EBW machine started from April 2011.Vertical lathePress machine (servo control)

Measuring system for half cell shape (Under developing)Chemical Polishing room

30 June 20114 Dumbbell, 8 Dumbbell EBW at Job-shop (June 2011 July 2011)

BeamBeam8 July 20116 July 201126

Fabrication of KEK-00 Cavity (w/o HOM)

Center cells (Nb) / EBW at job shopDumb-bell (Nb)Beam-pipe (Nb)End-cells (Nb)

Input-port pipe (Nb)

End-Plates (Ti) + Nb ringBeam-pipe (Nb)End-Plates (Ti) + Nb ringFlanges (Nb-Ti alloy)27Final EBW at Equator of End-Cell at Job Shop1 Dec. 2011Failure in the EBW at the equator of end-cell (cell#1)/ 120 kV, 30 29 mA.

VoltageBeamCurrentPosition of hole

Cell#128

The setup of EBW of KEK-00 to repair the hole of cell#1. Repair of 9-cell cavity KEK-00 by EBW30 Jan. 2012 (Mon.)

Small Nb piece was made and it was set into the hole.EBW29

EBW with 120kV, 20mA, and 5 mm/s.EBW beadEBW bead

Observation of repaired part and local grindingA picture of repaired part: inner surface of cell#1-equator, theta=237 deg. (1st Feb. 2012)

EBW beadEBW beadArea of EBW for repairing the hole of cell#1Observation by Kyoto camera

Local grinding was done for the inner surface of the repaired part of cell#1 by hand in order to make a smooth surface. (3 Feb. 2012).3031Surface treatment of 9-cell cavity (KEK-00)

Bulk EP (100 um), Degreasing (50 0C, 30 min), HPR (1.5 h), Annealing(4 h, 750 0C), and final EP (20 um).HPR (7 hours)Brushing of beam-pipe and HOM antenna.Degreasing with detergent (FM-20 2%) in hot bath (500C, 30 min).

BrushingVertical Test Result of 9-cell cavity w/o HOM (KEK-00)32

Cell#1 (repaired cell) reached to 42.7 MV/m in the 6pi/9 mode. Limitation in the pi mode might be quench at cell#8, because the T-mapping sensor detected higher temperature in cell#8 in coincidence with the quench at 29 MV/m.Eacc = 29 MV/mQ0 = 9 x 10^933Future Plan of Cavity Fabrication Facility (CFF) ActivitiesFY 2011FY2012 9-cell cavity: KEK-00 without HOMApril 9-cell cavity: KEK-01 with HOMMachining of all parts by KEKEBW of all seams at CFF(KEK)AprilFabrication 9-cell cavities: KEK-02 with HOMSingle-cell cavity for FJPPL collaborationSurface preparation and VTSurface preparation and VTStudy for the high-pressure code applicationThis cavity will be used for the vertical EP test at Saclay.FabricationFabricationSummary of KEK activitiesAll equipment (press machine, CP room, EBW machine, etc) were installed in Cavity Fabrication Facility (CFF).

9-cell cavity KEK-00 (w/o HOM) was fabricated. Center cells were EBWed at job shop and end-groups were EBWed in CFF(KEK).

Final EBW of KEK-00 cavity at the equator of end-cell was failed, but it was repaired. After surface preparation at KEK, KEK-00 reached to Eacc = 29 MVm in vertical test. 9-cell cavity KEK-01 and -02 (w/ HOM) will be fabricated where all seams will be EBWed at CFF(KEK) in FY2012.

We will fabricate a single-cell cavity in CFF at KEK. This cavity will be used for the study of vertical EP at Saclay in the frame-work of FJPPL collaboration.

3434- F. Eozenou / T. Saeki - A_RD_0535OBJECTIVE FOR FY 2012May 28th 2012

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Plan of Collaboration with Single-Cell Cavity36Fabrication of a single-cell cavity at CFF(KEK). This cavity will be used for the study of vertical EP at Saclay in the frame-work of FJPPL collaboration.

Fabrication of single-cell cavity at CFF(KEK).Vertical EP of the cavity and vertical test at Saclay.

May 28th 2012- F. Eozenou / T. Saeki - A_RD_0537

ON-GOING SAMPLES EXPERIMENTS

Same contaminants observedQuantities differ (Sulfur)More sulfur found at iris at KEKElectrodes configuration incriminated EP @ KEK. Rotating Nb samples.EP @ Saclay. static Nb samples.Samples measurements on cavities @ KEK.4 samples will be EPed, 4 different anode-cathode distance (Saclay)Packing in Cleanroom in dedicated boxAnalysis of samples (KEK)

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37May 28th 2012- F. Eozenou / T. Saeki - A_RD_0538

COMPARISON HEP/VEPHEP @ KEKVEP @ Saclay2 advanced equipmentsEfficiency of HEP demonstratedExperience necessary for VEPUnique opportunity for fruitful comparison

KEK HEPed cavity shipped to SaclayVEP @ SaclayVT @ SaclayComparisonCEA DSM Irfu

May 28th 2012- F. Eozenou / T. Saeki - A_RD_0539ON-GOING GRIDING/WIPING EXPERIMENTS

KEK Grinder makes it possible to treat equator and irisNew head under development to reach any part of a cellSaclay Cavity with pits sent to KEKLocal grinding of the defectsCavity shipped back to Saclay for VT

Additional sponge-wiping of contaminated cavity

Saclay cavity with pitsSaclay cavity with FEKEK grinding systemKEK wiping systemCEA DSM Irfu

40THANK YOU FOR YOUR ATTENTION- F. Eozenou / T. Saeki - A_RD_05May 28th 2012

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