A beam profile measurement in the ACCEL 250Â MeV medical proton cyclotron

The result of a beam profile measurement in the first turn after the internal ion source of the 250 MeV ACCEL compact medical proton cyclotron is presented and compared to beam profiles obtained by orbit tracking computations. The comparison allows to determine parameters like puller voltage, average start energy of the protons and shape of the plasma boundary by fitting the computed beam contour to the measured profile.