BEAM POSITION MONITOR DEVELOPMENT FOR ITHEMBA LABS CYCLOTRON BEAM LINES*

At iThemba LABS intense proton beams, accelerated in a K=200 MeV separated-sector cyclotron with a K=8 MeV solid-pole injector cyclotron, are utilized for the production of radioisotopes and particle radiotherapy. Low intensity beams of light and heavy ions as well as polarized protons, pre-accelerated in a second injector cyclotron with a K-value of eleven, are available for nuclear physics research. Beam position measurement and alignment are done semi-destructively with profile grids at beam intensities of less than 1 µA. A prototype beam position monitor and associated computer-controlled electronic equipment have been developed for non-destructive alignment and continuous display of the beam position in the beam lines for the more intense beams used for therapy and the production of radioisotopes. iThemba LABS developed and manufactured the four section strip-line monitor chamber. The electronic equipment was developed at the Forschungszentrum Jülich-IKP, as part of the work done under a Scientific and Technological Agreement between Germany and South Africa. The equipment, consisting of an RF signal processing module (BPM-RF) and a data acquisition and control module (BPM-DAQ), sequentially measures and processes the monitor signals and delivers calculated horizontal and vertical beam position data via a serial network