MICE RFCC Module and 201 MHz Cavity Update Steve Virostek Lawrence Berkeley National Lab MICE CM23...

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MICE RFCC Module and 201 MHz Cavity Update Steve Virostek Lawrence Berkeley National Lab MICE CM23 at ICST, Harbin January 15, 2009
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Transcript of MICE RFCC Module and 201 MHz Cavity Update Steve Virostek Lawrence Berkeley National Lab MICE CM23...

  • MICE RFCC Module and 201 MHz Cavity UpdateSteve VirostekLawrence Berkeley National LabMICE CM23 at ICST, Harbin January 15, 2009

  • Engineering design of the RFCC module has been under way at LBNL since early last yearPreliminary and final design reviews were conducted last yearCoupling coil design and fabrication is being provided by ICST at Harbin (following talks)MICE cavity design is heavily based on the successful MuCool 201 MHz prototype RF cavityFabrication techniques and post processing Engineering design of the RF cavity is complete Cavity fabrication contract to be placed soonSignificant progress on RFCC module engineering designComplete CAD model of the cavity, tuners, support and vacuumInterfaces, shipping, assembly and installation (earlier talk)Overview

  • RFCC Module

  • RFCC PDR and FDR completed during CM21 and CM22201 MHz cavity detailed design and analysis is completeQualification of three cavity fab vendors completed late last yearRFP for cavity fab released by LBNL this week (responses due 1/30)Copper cavity material to arrive at LBNL next weekCavity tuner RF & structural analyses and CAD model are completeStructural analyses of cavity suspension system is completeRF coupler based on design previously developed for MuCool cavityCoupling coil interface agreed upon with ICST (a few details remain)Cavity cooling water feedthrough concept has been developedConceptual design and CAD model of module vacuum vessel, vacuum system and support structure is completeShipping, assembly and installation presented earlier this weekProgress Summary

  • Eight 201-MHz Cavities for MICEEight 201-MHz RF cavitiesRFCC modules

  • MICE RF Cavity SummaryDesign based on the successful US MuCool prototypeA slight reduction in cavity diameter to raise the frequency has been specified and analyzedThe fabrication techniques used to produce the prototype will be used to fabricate the MICE RF cavitiesFinal cavity design was reviewed at CM22 at RALCopper cavity material will arrive at LBNL next weekAn RFP for cavity fabrication has been released, and a contract is expected to be placed next monthThe first 5 cavities to be delivered by end of CY2009

  • MICE RF Cavity Design3-D Microwave Studio RF parameterized model including ports and curved Be windows to simulate frequency, Epeak, etc.Frequencies variation between cavities should be within 100 kHz ApproachSlightly modify prototype cavity diameter Target a higher cavity frequencyTune cavities close to design frequency by deformation of cavity body (if needed)Tuners operate in the push-in mode only lower frequency

  • Cavity Design ParametersThe cavity design parameters Frequency: 201.25 MHz = 0.87Shunt impedance (VT2/P): ~ 22 M/mQuality factor (Q0): ~ 53,500Be window diameter and thickness: 42-cm and 0.38-mmNominal parameters for MICE and cooling channels in a neutrino factory 8 MV/m (~16 MV/m) peak accelerating fieldPeak input RF power: 1 MW (~4.6 MW) per cavity Average power dissipation per cavity: 1 kW (~8.4 kW)Average power dissipation per Be window: 12 w (~100 w)

  • 201 MHz Cavity ConceptSpinning of half shells using thin copper sheets and e-beam welding to join the shells; extruding of four ports; each cavity has two pre-curved beryllium windows, but also accommodates different windows

  • Cavity FEA AnalysisRF, thermal and structural cavity analyses carried out using a single ANSYS modelThe thermal solution provides the temperature distribution throughout the cavity and Be windowHeat fluxes on inward curving windows are 60% higher than for outward curving windows (with correspondingly higher DT)Peak temperature occurs at center of inwardly curved beryllium window (86 C) using Nominal Neutrino Factory parameters (MICE is 4 times lower)Cavity RF FEA ModelTemp plot w/windowTemp plot w/o windowCavity Body FEA Model

  • RF Cavity Fabrication OverviewCavity half-shells will be formed using a metal spinning techniquePrecision computer controlled milling of large parts (1.2 m diameter) Precision turning of mid-sized parts (0.6 m diameter)Precision manufacture of smaller partsTo prevent annealing and maintain cavity strength, e-beam welding will be used for all cavity weldingweld joints: cavity equator, stiffener rings, nose rings, port annealing and port flangesCavity inside surfaces are finished by mechanical smoothing and electro-polishingEngineering CAD Model of the RF CavityPrototype RF CavityThe same fabrication techniques used to successfully fabricate a prototype cavity will be used to fabricate the MICE RF cavities

  • Cavity Fabrication DrawingsDetailed fabrication drawings are completeAll steps of cavity fabrication process are detailedDrawings provided to vendors for bidding process

  • Cavity Fabrication Process Traveler

  • A series of vendor qualification visits were conductedApplied Fusion - San Leandro, CAe-beam welding, machiningMeyer Tool & Mfg., Inc. - Chicago, ILmachiningRoark Welding & Engineering - Indianapolis, INe-beam welding, machiningSciaky, Inc. - Chicago, ILe-beam weldingACME Metal Spinning Minneapolis, MNcavity shell spinningMidwest Metal Spinning, Inc. Bedford, INcavity shell spinningCavity Vendor QualificationPrimary vendors

  • Meyer Tool & Manufacturing, Inc.4601 W. Southwest HighwayOak Lawn, Illinois 60453

    Meyer uses Sciakys e-beam welding service at the Sciaky factory close to Meyer Tool (Sciaky is a major e-beam welder manufacturer)

    Meyer Tool has the machining equipment necessary to fabricate the complete RF cavity (minus spinning)

    A complete drawing package, specification and request for quote has been presented to Meyer ToolMeyer Tool & ManufacturingSciaky electron beam welding machine

  • C.F. Roark Welding & Engineering Co, Inc. 136 N. Green St. Brownsburg, IN 46112Roark Weldings e-beam welder is a Sciaky machine and it is housed in an isolated room with a positive air flow to help maintain cleanliness

    Roark Welding has the machining equipment necessary to fabricate the complete RF cavity (plus spinning at an outside vendor)

    A complete drawing package, specification and request for quote has been presented to Roark Welding

    C.F. Roark Welding & Engineering Co, Inc.Sciaky electron beam welding machine at Roark

  • Applied Fusion, Inc.Applied Fusion, Inc.1915 Republic Ave.San Leandro, CA 94577

    Applied Fusions e-beam welder is a German made machine

    Applied Fusion has the machining equipment necessary to fabricate the complete RF cavity (minus spinning)

    A complete drawing package, specification and request for quote has been presented to Applied FusionElectron beam welding machine

  • Overall RFCC Module DesignDynamic Cavity Frequency TunersHexapod StrutCavity SuspensionRF Cavity Water CoolingMechanical Joiningof the Coupling Coiland the Vacuum VesselVacuum SystemRF Coupler

  • Progress: Other Module ComponentsDesign and analysis of the cavity frequency tuners is complete, drawings to be done soonA hexapod cavity suspension system has been incorporated in the designThe RF coupler will be based on the SNS design using the off the shelf Toshiba RF window The vacuum system includes an annular feature coupling the inside and the outside of the cavityVacuum vessel accommodates interface w/coupling coilBeryllium window design is complete; windows are in the process of being ordered (8 per module needed)

  • Cavity Tuner ConfigurationTuners touch cavity and apply loads only at the stiffener ringsTuners operate in push mode only (i.e. squeezing)Tuning automatically achieved through a feedback loopSoft connection only (bellows) between tuner/actuators and vacuum vessel shellSix tuners are spaced evenly every 60 around cavityClocking of tuner position between adjacent cavities avoids interferenceNo contact between pairs of close packed cavities

  • Cavity Tuner Components - Section ViewBall contact onlyDual bellowsvacuum sealingTuner actuatorPivot pinFixed (bolted)connectionCeramic contact wear plate between actuator ball end and tuner arm

  • Tuner Component DetailsFixed armPivoting armActuator with integrated bellowsassemblyScrews to attach tuner to the cavity stiffener ringPivot pinCylinder attachment bracketForces are transmitted to the stiffener ring by means of push loads applied to the tuner lever arms by the actuator assembly

  • Tuner Actuator DesignActuator design uses dual bellows vacuum-to-air sealing (no rubber)Actuator is soft mounted to the vacuum vessel with a bellowsCeramic plate on tuner armHemisphere on actuator rod end Senior Aerospace Bellows will supply the actuators (near off the shelf)

  • Cavity Tuning ParametersThe following parameters are based on a finite element analysis of the cavity shell. Tuning range is limited by material yield stress.Overall cavity stiffness: 7953 N/mmTuning sensitivity: +230 kHz/mm per sideTuning range: 0 to -460 kHz (0 to -2 mm per side)Number of tuners: 6Maximum ring load/tuner: 5.3 kNMax actuator press. (100 mm): 1.38 MPa (200 psi)

  • Tuner System AnalysisModel of overall cavity tuning displacementsMaximum distortion of 0.05 mm (0.002) in the stiffener ringOne tuner FEA of 1/6 cavity segmentMaximum cavity stress is 100 MPaCavity will not yield when compressed to full tuning range

  • Cavity Support: Hexapod Strut SystemExample of a hexapod stageDedicated six-strut hexapod system for each cavity will provide kinematic supportThis system spreads the cavity weight across several strutsStrut arrangement provides stiff and accurate cavity supportKinematic mounts prevent high cavity stresses due to thermal distortion and over-constraint

  • Hexapod Strut Cavity MountsCopper mounting block will be e-beam welded directly to the RF cavityThe cavity is very stiff at mounting block locationOpposite end of strut connects to stainless steel mounting block welded to the vacuum vessel

  • Hexapod Strut Mounting to VesselStainless steel strut mounts welded to the inside of the vacuum vesselCopper strut mounts e-beam welded to the outside of the cavity

  • Cavity Suspension AnalysisStress AnalysisPeak cavity stress due to gravity is the 20-30 MPa (~10% of yield)Deflection AnalysisTotal mass of cavity assembly is ~410 kgPeak deflection: 115 mmModal AnalysisFirst mode frequency: 43 Hz

  • Cavity Cooling SystemSingle circuit water cooling tube for each cavityOne inlet and one outlet8 penetrations in the vacuum vessel

  • Cavity Cooling Water FeedthroughsAll cavity water connections are made outside of the vacuum vesselContinuous water tube wrapped around the cavity Compliance coil inside of the vacuum vesselOne inlet and one outlet per cavity

  • Section View of Water FeedthroughsA conflat flange is welded into the wall of the vacuum vesselEnds of copper tubes are brazed into a 2nd special conflat flange The flange is fastened from the outside of the vacuum vesselVacuum sideAir side

  • Prototype Cavity RF CouplersCoupling loops are fabricated using standard copper co-axParts to be joined by e-beam welding (where possible) and torch brazingCoupling loop has integrated coolingThe RF coupler will be based on the SNS design using the off the shelf Toshiba RF window

  • MICE Cavity RF CouplersA bellows connection between the coupler and the vacuum vessel provides compliance for mating with the cavity

  • MICE Cavity RF CouplersOff the shelf flange V clamp secures RF coupler to cavity

  • Vacuum SystemA NEG pump has been chosen because it will be unaffected by the large magnetic field A vacuum path between the inside and outside of the cavity eliminates the risk of high pressure differentials and the possible rupture of the thin beryllium windowNEG (non-evaporable getter) pump

  • Vacuum Vessel FabricationVacuum vessel material must be non-magnetic and strong therefore 304 stainless steel will be usedThe vacuum vessel will be fabricated by rolling stainless steel sheets into cylindersTwo identical vessel halves will be fabricated with all ports and feedthroughs

  • Two Halves Joined (w/o coupling coil)Central under-cut provides clearance for the coupling coil

  • Vacuum Vessel and Coupling Coil

  • Cross Sectional View with the Coupling CoilGap between the vacuum vessel and the coupling coil provides clearance for assemblyVessel welded around the inside after coupling coil and the second vessel half are in place

  • Vacuum Vessel Interface to Coupling CoilLBNL will weld two 25 mm thick special gussets, which are designed to match the gusset welded to the coupling coil at Harbin, to the vacuum vessel

  • Sixteen gussets will be used, 8 on each side of coupling coilVacuum Vessel Interface to Coupling Coil

  • RFCC Module Support StandBecause a special skid will be used for shipping and moving the RFCC into the experiment hall, the permanent support stand is bolted onto the vacuum vessel (not welded) The support stand will be fabricated of stainless steel

  • RFCC Attachment to Support StandThe vacuum vessel is bolted to a saddle made of stainless steel plates welded to the support standStainless steel bars are welded onto the vacuum vessel for attaching bolted gusset platesBolted gusset mounting bars

  • RFCC Support StandRFCC support stand must withstand a longitudinal force of 50 tons transferred from the coupling coilBolted gussets and cross bracing provide shear strength in the axial direction (analysis will be done to confirm this stand design)

  • Liquid Nitrogen Cooling ConsiderationsSuspension of cavities on struts provides low heat leak from cavity to vacuum vesselBeryllium window FEA thermal analysis will need to be performed with new parametersThe cavity frequency will be shifted (approximately 600 kHz) therefore tuning system or RF power source modifications will be neededInsulators will need to be added to the RF couplersCoaxial LN feedthrough tubes will be needed to insulate the connection outside of vacuum

  • Current Plan Moving ForwardCopper plates (20 each) are to arrive at LBNL next weekVendor bids for cavity fabrication are scheduled to be sent to LBNL on January 30thAssessment of bids and placing of contract to occur in FebruarySelected vendor will deliver two sets of 5 cavities that are complete and ready for interior electropolishingSpinning of shells will be specified and contracted separately by LBNL or optionally by cavity vendorFinal design and detailing of other module components is now starting fabrication of prototype parts to begin soonIntegration of cavities, coupling coils and other module components will take place at LBNL

  • Schedule OverviewRFCC design and fabrication project originally expected to be a 3year project (10/06 to 10/09)Coupling coil effort began in 2006 at ICST (Harbin)Design and fabrication of other RFCC module components was scheduled to begin 10/07Start was delayed due to lack of availability of qualified manpowerEarlier last year, mechanical engineer A. DeMello joined MICE to work on RFCC module design (FTE)Some additional (part-time) manpower now available

  • Manpower SummaryAllan DeMello: lead ME for RFCC Module design & fab3D engineering CAD model, cavity analysis, design & fabFull-time on RFCC module designNord Andresen: design/fab of module subcomponentsCavity tuners, support structure, vacuum vessel, procurementsgeneration of fabrication drawings50% time design/engineering supportSteve Virostek: engineering oversight for MICE at LBNLDerun Li: cavity physics design and oversightMike Green: coupling coil design & interface with module

  • Schedule Summary

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