Mu2e Superconducting Solenoids

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Mu2e Superconducting Solenoids. Michael Lamm Fermilab TD/Magnet Systems Dept. Mu2e/Comet Joint Workshop January 24, 2009. Talk Outline. Mu2e Magnet System Description Present State of Magnet Design for Mu2e Design Issues Possible collaboration with COMET collaboration. - PowerPoint PPT Presentation

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<ul><li><p>Mu2e Superconducting SolenoidsMichael LammFermilab TD/Magnet Systems Dept. </p><p>Mu2e/Comet Joint WorkshopJanuary 24, 2009</p><p>Mu2E/COMET Joint Workshop</p></li><li><p>Talk OutlineMu2e Magnet System DescriptionPresent State of Magnet Design for Mu2eDesign IssuesPossible collaboration with COMET collaboration</p><p>Mu2E/COMET Joint Workshop</p></li><li><p>History of Muon System DesignMu2e baseline is the the MECO solenoid systemConceptual Design completed in 2002Cost and schedule as well as technical detailsSeveral incremental improvements to design 2002-2005Documented in reviews and internal notesBut CDR was never updatedCDR and subsequent design improvements were favorably reviewed several times</p><p>Mu2E/COMET Joint Workshop</p></li><li><p>Magnet System by Cryostat and PoweringProduction SolenoidSingle Cryostat: pool-boilingSingle power supplyTransport SolenoidTwo cryostats: Indirect coolingFour power suppliesNo iron shielding envisionedKapton windowDetector SolenoidSingle Cryostat: Indirect coolingSingle Power supplyDesigned for independent cooling and powering</p><p>Mu2E/COMET Joint Workshop</p></li><li><p>Mu2e Coil DesignSystem consists of 96 coil units (~80km of SSC cable)Fields 1-5 T, Aperture 1-2 meters, 1.5-4 kA excitationVery large operating margin in current density, field and temperatureConductorSSC cable soldered into a half hardened copper barInsulated with glass tape and KaptonStabilizer is sized for Production, Transport and Capture target requirementsStructureepoxy vacuum impregnatedouter mandrel for hoop stressCoils series-connected through soldered splice joints</p><p>Copper BarSSC cableLDX Coil </p><p>Mu2E/COMET Joint Workshop</p></li><li><p>Mu2e Quench ProtectionDigital Quench Protection with analog backupInputCalculated Inductance Matrix and Splice ResistanceMonitor voltage across each coil, power supply current I(t)Upon quench (deviation from expect voltage over long integration time)Extract current from quenched magnet through external dump resistorOther magnets brought down in orderly fashionDesign peak voltage to ground (1kV)Design peak spot temperature ~150K</p><p>Mu2E/COMET Joint Workshop</p></li><li><p>Mu2e and the MECO Magnet SystemMu2e is studying the Meco designFace to face meeting with magnet designers(MITGA)Developing proposal with General Atomics (GA) to assemble and documents to produce an updated CDRTime frame: 4 monthsWe will use this time to investigate ways to make the Mu2E solenoid system more efficient i.e.:Produce more capturable muons/incident proton, less backgroundFor less money and as quickly as possible (since the magnet system seems to be the cost and schedule driver for the experiment)</p><p>Mu2E/COMET Joint Workshop</p></li><li><p>Areas of Investigation from Baseline Mu2ePunt on the reflected pions/muons in the production solenoidEliminate highest field solenoidForward production is swept from the magnets: less nuclear heatingIndirect cooling then may be possibleGo away from SSC conductor to wider cable Higher current, but less turns, lower inductanceMay be easier to buildSub-divide magnet system into smaller units for poweringMore effective extraction, reduce the amount of stabilizerWith HTS leads, helium consumption penalty is substantially reducedHave to weigh against added cost of HTS leads, extraction circuits, PS etc.Use of other conductorsFor e.g., use of Aluminum stabilized conductor. Related to this..Look for synergies with COMET experiment</p><p>Mu2E/COMET Joint Workshop</p></li><li><p>Possible Areas of Mu2e/Comet Magnet CollaborationWhile there are several commonalities in the magnetic design.Common goal of maximizing clean capturable muonsthere are significant differences in the actual magnet designsA large driver is the conductor choice which greatly influences mechanical and quench designsConductor development (Aluminum stabilized conductor) is a logical place to consider collaborationCould have significant benefits for Mu2e designBut need to make clear case for moving away from baselineCOMET has some concerns that need to addressed about the availability and affordability of the aluminum stabilized conductor on the market todayVendors who will bid on magnet fabrication may have a preference towards a particular technology Most detector solenoids in recent times built with stabilizer AlShould be prepared to consider all reasonable proposals</p><p>Conductor development</p><p>Mu2E/COMET Joint Workshop</p></li><li><p>Areas of Collaboration IIUnder discussion is a proposal under the US-Japan agreement to study muon beamline magnetsIn particular, the parts of the proposal addressing Al stabilized NbTi, are very well aligned with the near term interests of both Mu2E and Comet. Hopefully this program, if approved, will produce conductor in the 2010 that would be timely for Mu2e/Comet tests and prototypes. The immediate need for a realistic detailed conductor specificationIn the case of Mu2e, conceptual design studies with Al stabilizer should be performed in parallel with the Meco CDR updates (i.e. in the next 6 months)Therefore, we should develop as soon as possible a conductor specification with realistic attainable Jc and good structural propertiesAligned with US-Japan agreement Near term need for practice conductorWe would ask that in the very near future, some conductor is identified, either from surplus or available from industry that could be used to practice winding coils in the near future. If possible this conductor should be as close as possible to the future base line conductor. </p><p>Mu2E/COMET Joint Workshop</p></li><li><p>Focus on Design of Pion-Production Solenoid</p><p>Recognizing similarities in function of Pion-Production Solenoids for Mu2e/COMETUsing common conductor designSelect a few design studies of mutual interestsPossible topics:Quench protection of coupled solenoids under various power schemesHeat load studies on production solenoids from particle production under various shielding scenarios. This would require coordination with particle production models, particle interaction models like MARS as well as the magnet quench codes, which would be a good cross check on the two experiments.Agree on sensible thermal and quench margins, safe differential thermal contractions due to quenches, based on previous detector practices. There are probably other studies that could be proposed. </p><p>Mu2E/COMET Joint Workshop</p></li></ul>

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