Please use this identifier to cite or link to this item: https://www.um.edu.mt/library/oar/handle/123456789/67332
Title: The development and optimisation of the B-train system for the ELENA ring
Authors: Grech, Christian
Keywords: Synchrotrons
Magnetic fields
Magnetic fields -- Measurement
Issue Date: 2020
Citation: Grech, C. (2020). The development and optimisation of the B-train system for the ELENA ring (Doctoral dissertation).
Abstract: In synchrotrons, the vertical magnetic field produced by dipole magnets guides charged particles along a closed horizontal orbit, determined by the equilibrium of the centripetal force and the Lorentz force. As a result, the knowledge of the magnetic field value in real-time is essential to control the trajectory of the particles. Subsequently, a direct magnetic field measurement inside a reference magnet, known as a B-train, is used to derive an estimate of the average magnetic field in the ring. As part of a site-wide consolidation project, all the B-train systems at CERN are being replaced with upgraded electronics, software, and sensors. The Extra Low ENergy Antiproton (ELENA) ring is a new decelerator being built at CERN; hence a B-train system is required to be installed and commissioned. The ELENA ring presents challenges to magnetic field measurement systems, such as very low magnetic field and long cycle times. The aim of this thesis is to commission a measurement model for the ELENA B-train, as well as validating and optimising the instrumentation. A measurement model is thus developed in this thesis, and applied to identify the ring and reference magnets, the sensors, as well as the electronic acquisition chain. An uncertainty estimation helps identify the biggest sources of error in the measurement, providing an insight on potential improvements in the measurement system. The ELENA B-train system is validated through a series of tests, characterising the behaviour of the sensors, the stability and the accuracy of the instrument in operating conditions, confirming a relative reproducibility and accuracy better than 2 units (10−4). A potential improvement in the measurement by changing the position of the local field sensors is investigated, and the feasibility of applying a displacement is discussed for the ELENA B-train. A magnetic field model based on the decomposition of the field into different components is finally proposed. The model is tested using the ELENA magnetic cycles, exhibiting a relative accuracy of 1 unit, giving confidence in its prediction ability in low-energy synchrotrons.
Description: PH.D.
URI: https://www.um.edu.mt/library/oar/handle/123456789/67332
Appears in Collections:Dissertations - FacICT - 2020
Dissertations - FacICTMN - 2020

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