New developments of high current beam profile monitors for ion accelerators applied to fusion material research
Today particle accelerators have become key instruments in different areas, from materials science to healthcare. While many more disciplines find in them a tool suited to their needs, they must specialize and adapt to produce new types of particle beams. In the case of ion accelerators, the need fo...
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| Tipo de recurso: | tesis doctoral |
| Fecha de publicación: | 2020 |
| País: | España |
| Institución: | Universidad Complutense de Madrid (UCM) |
| Repositorio: | Docta Complutense |
| Idioma: | inglés |
| OAI Identifier: | oai:docta.ucm.es:20.500.14352/11092 |
| Acceso en línea: | https://hdl.handle.net/20.500.14352/11092 |
| Access Level: | acceso abierto |
| Palabra clave: | 539.1.076(043.2) Aceleradores de partículas Particle accelerators Física nuclear Partículas 2207 Física Atómica y Nuclear 2208 Nucleónica |
| Sumario: | Today particle accelerators have become key instruments in different areas, from materials science to healthcare. While many more disciplines find in them a tool suited to their needs, they must specialize and adapt to produce new types of particle beams. In the case of ion accelerators, the need for higher currents and powers to increase secondary particle production pushes classic diagnostics to their limit. When the beam profile is measured in these high current and power accelerators, the interceptive diagnostics are not capable of withstanding the high power deposition and are destroyed, hence the need for other types of diagnostics, in order to measure and monitor the profile. With high current beams there are different methods, all of them minimally invasive, based on the interaction of the beam with external particles. In this work we will focus on how to use the fluorescence light emitted in the electronic transitions caused by the action of the beam on the atoms and / or molecules of the surrounding gas, either the residual left by the vacuum or injected externally. The present work begins with several introductory chapters on the subject, where a justification of the current needs for accelerators is given, followed by an overview of the different beam diagnoses. Then it focuses on the theoretical and practical aspects of Fluorescence Profile Monitors. The discussion moves to the different effects that produce a distortion of the beam profile, with a special emphasis on the drift of excited particles before decaying to stable levels emitting photons, presenting two approaches to correct the profile measurements. The following chapters deal with about the experimental work done. The results obtained during one of the start-up stages of the LIPAc accelerator injector are presented first, where the profiles acquired with an intensified CID camera and a Doppler spectrometer are analyzed and compared with those obtained with an Allison scanner. Due to the minimal configuration of the ion source, with the diagnostics located just behind the acceleration column, much information could be obtained about the working conditions of the injector. The discussion then moves on to the design of the Fluorescence Profile Monitors for the high radiation areas of the DONES deuteron accelerator, where the high radiation dose and the strict beam requirements push the capabilities of the current Profile Monitors to the limit. Fluorescence. Finally, the design, manufacture and results of an experiment to measure the impact of different gases and lithium vapor on the profiles measured with protons of various energy MeVs are presented, where extensive work has been carried out to guarantee a Safe system due to the presence of liquid metals and compatible with the flexibility required by scientific needs. The thesis ends highlighting the main conclusions of the work carried out. In the profile distortion section, the validity of the method is correct and is in agreement with the results of the simulations when the initial assumptions are fulfilled. The results obtained during the start-up of the LIPAc injector have been of great help, since they showed a misalignment in the acceleration electrodes, as well as inconsistencies between the measurement of the fluorescence profile and that obtained with the EMU. Finally, the conclusions and future steps in the design of the new Fluorescence Profile Monitor for the high radiation areas of DONES are presented, together with the associated experiment, highlighting the importance of the radiation background in the performance of the detector. |
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