Parrella, Alessandro (2018) Magnetic material characterization and magnet axis displacement measurement for particle accelerators. [Tesi di dottorato]

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Item Type: Tesi di dottorato
Lingua: English
Title: Magnetic material characterization and magnet axis displacement measurement for particle accelerators
Creators:
CreatorsEmail
Parrella, Alessandroalessandro.parrella@cern.ch
Date: 11 December 2018
Number of Pages: 149
Institution: Università degli Studi di Napoli Federico II
Department: Ingegneria Elettrica e delle Tecnologie dell'Informazione
Dottorato: Information technology and electrical engineering
Ciclo di dottorato: 31
Coordinatore del Corso di dottorato:
nomeemail
Riccio, Danieledaniele.riccio@unina.it
Tutor:
nomeemail
Liccardo, AnnalisaUNSPECIFIED
Ramos, PedroUNSPECIFIED
Date: 11 December 2018
Number of Pages: 149
Uncontrolled Keywords: Instrumentation for particle accelerators, characterization of magnetic materials, superconductivity and magnet protection, cryogenic measurements, superconducting magnets.
Settori scientifico-disciplinari del MIUR: Area 09 - Ingegneria industriale e dell'informazione > ING-INF/07 - Misure elettriche e elettroniche
Date Deposited: 22 Jan 2019 22:46
Last Modified: 22 Jun 2020 09:46
URI: http://www.fedoa.unina.it/id/eprint/12661

Abstract

Bending and focusing magnets, both normal- or super-conducting, are crucial elements for the performance of any particle accelerator. Their design requirements are always more tighten regarding components’ misalignment and magnetic properties. This dissertation proposes new solutions for characterizing magnetic materials and monitoring solenoids’ magnetic axis misalignments. A superconducting permeameter is designed to characterize the new-generation superconducting magnet yokes at their operational temperature and saturation level. As proof of principle, the magnetic characterization of ARMCO® Pure Iron was performed at the cryogenic temperature of 4.2 K and a saturation level of nearly 3 T. A case study based on the new HL-LHC superconducting magnets quantifies the impact of the magnetic properties of the yoke on the performances of the superconducting magnets. A flux-metric based method is proposed to identify the relative magnetic permeability of weakly magnetic materials. As proof of principle, the magnetic properties of the ITER TF coils quench detection stainless steel are analyzed. This method is not suitable to test materials with a relative permeability lower than 1.1. Hence, a measurement system based on a new magneto-metric method is conceived and validated employing a standard reference sample. The methods proposed in this thesis are currently employed at CERN’s magnetic laboratory to face an increasing number of requests concerning not only the magnetic characterization of materials for magnets but also for shielding systems and compatibility of various components with high magnetic fields. In this thesis, the results of the evaluation of ARMCO® Pure Iron as the yoke of the new LHC superconducting magnets and CRYOPHY as the magnetic shield for the cryomodule prototypes of HL-LHC Crab Cavities are reported. Finally, a new Hall-sensor method is conceived and implemented for monitoring the coils alignment in multi-coil magnets, directly during their operation in particle accelerators. The proposed method is suitable even for those cases when almost the whole magnet aperture is not accessible. Requiring only a few measurements of the magnetic field at fixed positions inside the magnet aperture, the method overcomes the main drawback of the other Hall sensor-based methods which is having to deal with sturdy mechanics of the moving stages. The method is validated numerically on a challenging case study related to the Solenoid B of the project ELI-NP.

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