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arXiv · 2303.16738

Application of Distributed Fiber Optic Strain Sensors to LMQXFA Cold Mass Welding

M. Baldini·S. Krave·R. Bossert·S. Feher·T. Strauss·A. Vouris
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Abstract

The future High Luminosity upgrade of the Large Hadron Collider (HL-LHC) at CERN will include the low-beta inner triplets (Q1, Q2a/b, Q3) for two LHC insertion regions. The Q1, Q3 components consist of eight 10 m-long LMQXFA cryo-assemblies fabricated by the HL-LHC Accelerator Upgrade Project. Each LMQXFA Cold mass contains two Nb3Sn magnets connected in series. A stainless-steel shell is welded around the two magnets before the insertion into the cryostat. There is a limit on how much coil preload increase induced by the shell welding is allowed. Distributed Rayleigh backscattering fiber optics sensors were used for the first time to obtain a strain map over a wide area of a Nb3Sn magnet cold mass shell. Data were collected during welding of the first LMQXFA cold mass and the results confirm that the increase of the coil pole azimuthal pre-stress after welding do not exceed requirements.

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M. Baldini, S. Krave, R. Bossert, S. Feher, T. Strauss, A. Vouris. 2023-03-29. Application of Distributed Fiber Optic Strain Sensors to LMQXFA Cold Mass Welding. https://doi.org/10.1109/tasc.2023.3258904

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