Radiation Monitoring Experiment Using Thermoluminescent Dosimeter for the Tr 19 Cyclotron Area in Nuclear Research Institute

The core of Radiopharmaceuticals Research Centre, CCR, is represented by a TR19 cyclotron (Advanced Cyclotron Systems Inc.), a versatile and fully automated and computer controlled machine. This cyclotron accelerates negative ions (H), on a vertically arranged plane, up to 19 MeV energy, and is provided with two external beam lines and dual extraction capabilities. The main use is for the production of positron emitting radionuclide namely F, O, N and C. The pharmaceuticals labeled with these radioisotopes are used for positron emission tomography (PET) imaging. The radiation levels were measured in the facility at different locations namely cyclotron vault, control console, radiochemistry laboratory, beam extension room and the stack using a comprehensive computerized monitoring system. The thermoluminescent dosimeter, TLD, LiF: Mg, Cu, P are commonly used for the radiation dose measurements to determine the ambient dose equivalent, which are part of passive systems of environmental radioactivity monitoring. In this work TLD were distributed for a period of 87 days in 12 points of interest according to the map of the cyclotron area and were read out to determine the corresponding activities. All measured values were higher than those obtained in IFIN-HH nuclear research units so, at cyclotron vault point the ambient dose equivalent rate was 56 695 nSv/h.