Monte Carlo simulations for the design of the treatment rooms and synchrotron access mazes in the CNAO Hadrontherapy facility.

The Italian National Centre for Hadrontherapy is based on a synchrotron capable of accelerating protons and carbon ions up to 250 MeV and 400 MeV u(-1), respectively. The present work describes some Monte Carlo simulations performed to verify the design of the treatment rooms and synchrotron access mazes. The different shielding efficiency and induced activations of the common concrete and the baryte concrete were analysed. In such a radiation field, i.e. with high-energy neutrons, the baryte concrete gains twice the activation than the common concrete without any relevant dose reduction. Moreover, the simulations have stressed, again, the discrepancies between H*(10) and E in such cases where the neutron radiation field is the dominant component and, particularly, in the medium-high energy range.