Induction-coil transducers for measuring transversal field harmonics in accelerator magnets

The following thesis deals with the mathematical development, the numerical validation, the design, and the metrological characterization of an innovative sensor for magnetic measurements based on rotating coils. The developed mathematical model, linking experimental data and the field description in the aperture of magnets for accelerator, was numerically validated using simulated data. The validation results made it possible to check the correlation between measurements and the mathematical model itself. Furthermore, the numerical validation allowed to satisfy the constraints for the design and manufacturing tolerances of the sensor. The sensor that is required to perform local field distribution measurements along the magnet axis, must be not sensitive to the z-field component (namely to the field in the direction of beam travelling in the particle accelerator magnet). For this reason, the coil design is based on a certain number of loops placed on the same radius. This particular geometry has been called "Iso-perimetric". The sensor production, the transducer design, an innovative methodology for the sensitivity coefficients calculations and for the calibration procedure were carried out. Finally, the experimental results of the proof of principle of the first prototype, the design of the second prototype, and the measurements results are reported.