Study of the Extracted Beam Energy as a Function of Operational Parameters of a Medical Cyclotron

Abstract

The medical cyclotron at the Bern University Hospital (Inselspital) is used for both routine 18 F production for Positron Emission Tomography (PET) and multidisciplinary research. It provides proton beams of variable intensity at a nominal fixed energy of 18 MeV. Several scientific activities, such as the measurement of nuclear reaction cross-sections or the production of non-conventional radioisotopes for medical applications, require a precise knowledge of the energy of the beam extracted from the accelerator. For this purpose, a study of the beam energy was performed as a function of cyclotron operational parameters, such as the magnetic field in the dipole magnet or the position of the extraction foil. The beam energy was measured at the end of the 6 m long Beam Transfer Line (BTL) by deflecting the accelerated protons by means of a dipole electromagnet and by assessing the deflection angle with a beam profile detector.