Tomographical reconstruction of the horizontal phase space of a 3rd order slow resonant extracted proton beam of the MedAustron synchrotron

Abstract

The aim of this thesis is to determine the non-Gaussian particle distribution in the horizontal phase space extracted from a synchrotron accelerator via a slow resonant extraction process referred to as 'bar of charges'. A major issue associated with this undertaking is that a direct measurement of the phase space is not possible, whichin this study was circumvented by using tomographical reconstruction techniques. The required input data for the reconstruction algorithms (for simulations and measurements) were gathered by making use of the Phase Shifter Stepper module - a dedicated magnet setup designed at CERN for transverse phase space adjustments, implemented in the high energy beam transfer line at MedAustron. To date, no other accelerator facility has hosted such a module or has implemented it in such a way. Thus, the empirical evidence of the module's working concept is also presented here.The first section of this paper presents the results of tracking simulations relatingto questions regarding an appropriate measurement procedure, suitable reconstruction settings, meaningful particle distribution quantification parameters and useful data correction mechanisms. The second section presents the results of measurements performed with 250MeV proton beams and the relevant tomographical reconstructions provide visual evidence of the 'bar of charges' and confirm the theoretical descriptions of the slow extraction process. Furthermore, the applicability of the procedure (combination of adapted Phase Shifter Stepper working concept and tomographical reconstruction) is demonstrated by comparison of simulated and measured particle distributions. Finally, the impact of the measurement devices used on the results, limitations of the method itself as well as an outlook on time resolved reconstruction are discussed.