Accurate Displacement Measurements During the Powering of High Field Superconducting Magnets

Strain gauges have been the technique of choice for experimental stress analysis in superconducting magnets since the emergence of this magnet technology. Since then, important efforts have been taken to prevent and delimit strain measurement errors caused by magnetic fields and temperature changes. The maturity and relative simplicity of this technique has permitted the development of several force and displacement sensors that are able to work in the harsh conditions in which superconducting magnets operate, such as intense magnetic fields and cryogenic temperatures. This paper describes the methodology followed to develop and characterize a tailor-made displacement sensor and presents a successful application of this technology for the determination of displacements in the High Luminosity-Large Hadron Collider (HL-LHC) beam screen magnet quench testing campaign.