Fiber Bragg Grating Sensor as Valuable Technological Platform for New Generation of Superconducting Magnets

ABSTRACT New generation of superconducting magnets for high energy applications designed, manufactured and tested at the European Organization for Nuclear Resear ch (CERN) require the implementation of reliable sensors able to monitor the mechanical stresses affecting th e winding from fabrication to operation in magnetic field of 13 T. This work deals with the embedding of Fiber Bragg Grating sensors in a short model Nb 3 Sn dipole magnet in order to monitor the strain developed in the coil during the cool down to 1.9 K, the powering up to 15.8 kA and the warm up, offering perspectives for the replacement of standard strain gauges. Keywords: Superconducting coil, fiber optic sensor, FBG, dipole, Nb 3 Sn, strain 1. INTRODUCTION The development of a new generation of magnets for the Hi gh Luminosity upgrade of the Large Hadron Collider (HL-LHC) at the European Organization for Nuclear Research (CERN) requires the use of the more challenging superconductor Nb 3 Sn which has a higher magnetic field capability than the presently used NbTi. The goal is to allow a larger bore of the insertion magnets of the LHC within the same allowed space, leading to larger forces and larger magnetic fields in the magnets. A dedicated magnet, the Short Model Coil (SMC), was designed, manufactured and tested at CERN with the aim to study the applications of Nb