A shielding concept for the MedAustron facility

MedAustron is a synchrotron based accelerator facility for cancer therapy and research in Wiener Neustadt. The facility will provide protons up to kinetic energies of 250 MeV and carbon ions up to 400 MeV/n for ion beam therapy. Additionally, protons up to 800 MeV kinetic energy will be used in a dedicated room for non-clinical research. In order to obtain a shielding concept for this facility a detailed geometry of the accelerator facility was implemented into the Monte-Carlo code FLUKA and shielding simulations were performed. In order to account for uncertainties of the Monte-Carlo simulations and the fact that incorporation of radionuclides is contributing to the accumulated effective dose, all simulation results are evaluated with a safety factor of 10. We have followed an iterative process for optimizing shielding. The wall thicknesses were adapted to our demands, according to the simulation results. Then the geometry was adapted and simulations were repeated until the dose map met the requirements of legal dose limits. A detailed analysis of the radiation field compositions clearly shows that neutrons are the main contributors to ambient dose equivalent rates outside but also inside the shielding walls of MedAustron