A Two-Dimensional Non-Destructive Beam Monitoring Detector for Ion Beams

Abstract

A two-dimensional beam monitoring detector named π2 has been developed and tested at the Bern University Hospital, using an 18 MeV proton beam provided by a medical cyclotron. This non-destructive device utilises a scintillating compound (P47 phosphor) coated onto a thin aluminium foil that is angled at 45∘ with respect to the beam axis. The scintillating light produced when the beam passes through the foil is captured by a CMOS camera, resulting in a two-dimensional image of the beam profile. Custom software is then used to analyse the image and extract valuable information about the beam’s position, shape, and intensity. The focus of the experimental work was on characterising the performance of the π2 with the 18 MeV proton beam. The linearity of the detector’s output signal was evaluated for proton fluxes ranging from 2·1010cm−2·s−1 to 5·1011cm−2·s−1. Furthermore, the beam profiles measured with the π2 were found to be consistent with reference measurements obtained using alternative beam monitors. Additionally, the experiments also involved studying the beam scattering caused by the foil and scintillating layer. Finally, in a long-term radiation test, the detector demonstrated a stable response up to an integrated proton flux of 3·1015cm−2. The π2 is currently being used at the Bern cyclotron for monitoring beams in the development of new methods for medical radioisotope production and for radiation hardness studies. The π2 has potential applications in several fields that involve the use of accelerated ions, such as cancer particle therapy, medical radioisotope production and radiation hardness studies.