Résumé
In this work, the spatial profile of a very high-energy 208 Pb ion beam using two-dimensional detector arrays is characterized. The detector arrays are developed for quality assurance in radiotherapy with the capability of measuring two-dimensional dose distributions of patient treatment plans. The detector array Octavius Detector 1600 SRS (OD 1600 SRS) consists of liquid-filled ionization chambers suitable for low-intensity beams, whereas the Octavius Detector 1600 XDR (OD 1600 XDR) contains vented ionization chambers suitable for higher-intensity beams. Both detector arrays were implemented at the CHARM facility to characterize the spatial profile of a 208 Pb heavy ion beam that has been extracted from the CERN LHC with initial energies of 650 MeV/u, 750 MeV/u, 1 GeV/u and 2 GeV/u. Thereby, the stability of beam dimensions and shape at various energies and flux rates were quantified. The results were compared to those recorded by the multi-wire proportional chamber integrated into the beam line. Additionally, the time-dependent structure of beams at different settings has been investigated.