Digital Signal Processing Approach for Measurements of Non-Stationary Magnetic Field Through a Rotating Coils System

摘要

High energies physics is nowadays challenging the unprecedented opportunity of studying and investigating the ultimate constituents of matter and their interaction. Thanks to its superior energy level, Large Hadron Collider (LHC), currently under construction at CERN (Geneva), will allow a deep insight into elementary particles world. To create and study elementary particles, it is, in fact, necessary to assure that particles collides with one another with sufficient energy. Particles are kept on stable orbits by means of powerful superconducting dipole magnets, the magnetic field of which is capable of suitably bending particles trajectories; proper measurements of magnetic field turn out to be an advisable and strategic task. Standard procedure, based on the application of traditional DFT algorithm to flux samples acquired through a rotating coils system, has proven to be unreliable when magnets are supplied with non-stationary current ramping up to the value corresponding to the nominal operative magnetic field. The authors present hereinafter a digital signal processing approach to overcome standard procedure limitations. The approach is based on interpolation techniques and allows the evolution versus time of harmonic coefficients of the magnetic field to be accurately reconstructed. Several tests have been conducted on simulated flux samples to assess the performance of the proposed approach. Obtained results are presented and compared to those granted by standard procedure.