Measurement of activity of the predominant gamma-emitting radionuclides in activated components of a medical cyclotron plan

An identification and activity evaluation of the predominant gamma-emitting radionuclides in activated parts of a medical cyclotron plant by high resolution gamma-ray spectrometry were performed. The use of LaBr3:Ce scintillation and HPGe detectors was examined in order to solve the measurement problems due to high activity of some components used inside a plant provided with an IBA CYCLONE 18/9 cyclotron. For each component, the identification of some key-radionuclides allows to evaluate the surface dose behaviour as function of decay time. The largest activity values are related to radionuclides with half-life of 70-80 days, while radionuclides with higher half-lives represent less than 10 per cent of the total activity. The surface dose rate will be reduced to about 1/1000 of the starting value after a decay period of approximately 3 years, with a relatively safety at product disposal work.