Source and shielding calculations at a PET cyclotron and possible activation in the soil

This presentation summarizes the results of the Monte Carlo simulation of the shielding calculations and estimates of the soil activation for the new cyclotron of the HZDR (Helmholtz-Zentrum Dresden-Rossendorf). The dose values were determined on base of the resulting neutron flux at the 18F production. The calculations were carried out with the Monte Carlo code MCNP5. The neutron source was used both calculated with ALICE-91 code (manufacturer) and calculated with MCNP6. The comparison of the sources shows that ALICE-91 produced significantly fewer neutrons. The calculation of the soil activations was performed with FLUKA. In addition the effects of the energy increasing of the protons from 24 to 28 MeV were evaluated.
It could be shown that the expected total dose rate in the public area is about 0.1 mSv/h and thus significantly below the permissible value of 0.5 microSv/h. The activities generated in the soil are mainly determined by radionuclides with short half-life. After 5 years of continuous beam operation and a subsequent decay time of 30 days, the allowable value is used up only to 0.2%.