TE-MSC Group representative at ASC #1



Carlo Petrone (CERN)

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TE-MSC Seminar
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Carlo Petrone
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Sonja Sandell
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    • 1
      Status of the MQXFB Nb3Sn quadrupoles for the HL-LHC

      The cold powering test of the first two prototypes of the MQXFB quadrupoles (MQXFBP1, now disassembled, and MQXFBP2), the Nb3Sn inner triplet magnets to be installed in the HL-LHC, has validated many features of the design, such as field quality and quench protection, but has found performance limitations. Both magnets showed a similar phenomenology, characterized by very reproducible quenches in the straight part inner layer pole turn, with the absence of training and limiting the performance at 93% (MQXFBP1) and 98% (MQXFBP2) of the nominal current at 1.9 K, required for HL-LHC operation at 7 TeV. Microstructural inspections of the quenching section of the limiting coil in MQXFBP1 have identified fractured Nb3Sn filaments in strands located at one specific position of the inner layer pole turn, allowing to determine the precise origin of the performance limitation. In this seminar, we outline the strategy that has been defined to address the possible sources of performance limitation, namely coil manufacturing, magnet assembly, and integration in the cold mass.

      Speaker: Susana Izquierdo Bermudez (CERN)
    • 2
      Assembly and test results of the RMM1a,b magnet, a CERN technology demonstrator towards Nb3Sn ultimate performance

      As part of the High Field Magnet technology development carried out at CERN, demonstrators are under construction to explore the full potential of Nb3Sn. The Racetrack Model Magnet (RMM) is one of them, building upon the successful Enhanced Racetrack Model Coil (eRMC) eRMC1a magnet, which reached a 16.5 T peak field or 16.3 T bore field at 1.9 K. The RMM1a,b magnet is composed of the same two previously tested eRMC coils and an additional middle RMM coil. This central racetrack coil features a closed cavity with a diameter of 50 mm and a total length of 526 mm. The coil pack is assembled in the same shell-based support structure as eRMC1a, using bladders and keys to allow for precise control of the preload with minimal spring back and conductor overstress. The magnet was preloaded with a conservative approach limiting the peak stress in the coil blocks below 150 MPa. It was then successfully tested up to 16.7 T peak field, or 16.5 T bore field at 1.9 K. This seminar describes the assembly of the RMM1a,b magnet, relying on Finite Element Analysis (FEA) and mechanical instrumentation, as well as the powering test results at 4.2 K and 1.9 K.

      Speaker: Emma Gautheron (CERN)