Magnetic measurement of alignment of main LHC dipoles and associated correctors

We discuss the method developed for the verification of alignment of magnetic elements contained in the LUC cryodipole cold mass during series tests at CERN. First, we outline motivations and requirements and then we focus on test strategy, equipment and procedures. Our goal is to express the magnetic field of the dipole and of its associated correctors w.r.t. the reference beam line, not accessible during cryogenic tests. To do so, we use traveling harmonic coil probes ("moles") that allow simultaneous measurement of the field and of the coil position. A laser tracker is used to relate these measurements to fiducials. In the dipole, the axis of the quadrupole configured dipole is used as an intermediate reference for the transfer. We provide details on the devices used for measurements in warm and cold conditions, some results from prototypes and pre-series dipoles and an assessment of the precision expected for the series tests.