STUDY AND EXPERIMENTAL ANALYSIS OF AN INNOVATIVE METHOD FOR QUENCH LOCALIZATION IN SUPERCONDUCTING HIGH ORDER MAGNETS
Tesi di Dottorato
Data di Pubblicazione:
2021
Citazione:
STUDY AND EXPERIMENTAL ANALYSIS OF AN INNOVATIVE METHOD FOR QUENCH LOCALIZATION IN SUPERCONDUCTING HIGH ORDER MAGNETS / S. Mariotto ; supervisor: M. Sorbi ; coordinator: M. Paris. Università degli Studi di Milano, 2021 Mar 23. 33. ciclo, Anno Accademico 2020. [10.13130/mariotto-samuele_phd2021-03-23].
Abstract:
This Ph.D. thesis concerns the study of the quench propagation in the new High Order corrector superconducting magnets for the Large Hadron Collider upgrade project, called High Luminosity LHC, and the development of a magnetic field measurement system for their characterization. To better introduce the work performed on these types of superconducting magnets, a brief introduction to particle accelerators, and in particular particle accelerator colliders, is reported in Chapter 1. The introduction describes the basic concepts to further understand particle physics at high energy scales and the rules which govern particle interactions and their properties. It focuses mainly on the description of the magnetic field produced by a superconducting magnet and how the magnetic field quality can be measured and qualified. The new magnetic field measurement system, which has been used to measure and characterize the High Order corrector magnets, has been developed in a collaboration framework between INFN Milan and the CERN magnetic field measurement system department. This device is based on the classical rotating coil measuring system design with 5 PCB coils to achieve high levels of accuracy. A brief description of the theoretical frame of the rotating coil method for the magnetic measurement system is introduced in Chapter 1 highlighting the correlation between the magnetic field harmonics and the Fourier decomposition of the voltage induced in the rotating coil PCB. An introduction to the High Luminosity LHC upgrade project is reported in Chapter 2 to better describe the motivation and the requirements for the development of these new NbTi superconducting magnets on which this thesis work is performed. A detailed analysis of the magnet electromagnetic and mechanical designs is reported together with the description of the development of the new magnetic measurement system installed at the INFN-LASA laboratories in Milan. Being able to measure different types of HO corrector magnets in parallel during the same cryogenic test, the high rotational order of the magnets represents a challenge both for the calibration of the measurements and their accuracy. To optimize the design of the new magnetic measurement system, a set of electromagnetic 3D simulations have been performed on the final magnet configuration and assure that the cross-talking between the magnet during the cryogenic powering tests is negligible. The same set of simulations has been performed also for the configuration of the magnet when installed in the LHC lattice, to evaluate the performances in the final configuration, giving the same negligible cross-talking result. Finally, examples of real data of magnetic field quality, taken during the last phase of the prototype development and the first batch of the magnet series, are compared with the 3D electromagnetic simulations showing very good performances of the produced magnets. The quench protection study of the HO corrector magnets is reported in Chapter 3. A brief introduction to superconductivity is reported together with the description of the main problems which have to be faced during a quench development inside a superconducting magnet. The quench development and propagation inside the superconducting coils of the magnets have been studied focusing, at first, on the analysis of the coil material properties to reproduce experimental data. The superconductor wire and all the coil properties are described together with the comparison of the calculated differential inductance of the magnet with real data taken from the powering of corrector magnet prototypes. The simulations of the real quench that happened during both the prototype development phase and the series production, are in very good agreement with the simu
Tipologia IRIS:
Tesi di dottorato
Elenco autori:
S. Mariotto
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