Speaker
Description
One Best 35p Cyclotron is planned to be assembled and subsequently operated at CGN Mianyang, Sichuan in China. As a previous preparation for the arriving of this commercial accelerator, it is required to perform shielding calculations in order to verify and or improve the current proposed design for the facility — this proposed design is the one suggested by the manufacturer of the machine. This kind of nuclear installation is supposed to be used to produce a considerable wide range of typical and emergent medical isotopes used in the nuclear medicine area. Among them, we can mention gallium-68, germanium-68, technetium-99m, fluorine-18, etc. Different types of target materials and target physical states such as solid, liquid and gas can be employed at the target stations. This depends of the specific requirements to the use of medical radioisotope of the end user in the city. This cyclotron has the possibility of holding four irradiation beam lines. Then four irradiation routines can be carried out for different purposes at the same time.
In this work, we replicated the entire facility model given by the manufacturer using two CAD-based software. This replica contains exact information of the real dimensions to be executed during the construction of the installation. As we aim to use some Monte Carlo codes for the shielding calculations, this model is exported to SuperMC code in order to assign the materials of the facility and the materials of the shielded parts of the cyclotron. These shielded parts of the cyclotron include the different layers of the machine which are covering the accelerating cavities. SuperMC allows us to exactly export the concerning cards related to materials and geometrical aspect to Monte Carlo software such as PHITS, FLUKAs, etc. We plan to use the recent version of PHITS, and the recent versions of FLUKA by the current developers, namely CERN & SLAC. Therefore, we will be benchmarking three codes for the radiation shielding calculations. Physics quantities of interest and to be calculated with the three software include: ambient dose rate during the irradiation routine, ambient dose rate after some cooling time of the target, neutron flux during the irradiation routine, and long half-life activation products in the target after the bombarding process. This information at key physical points inside the entire facility will help us to verify and or correct some dimensions and materials for walls and doors. These outcomes will also give us insights the level of radiation exposure the workers will receive during the daily routines.