FLUKA Monte Carlo calculations for the design of the NEPIR fast neutron facility at LNL

The NEPIR (NEutron and Proton IRradiation) project foresees the construction of a fast neutron (En > 1 MeV) irradiation facility at the SPES cyclotron of the INFN Legnaro National Laboratory. The initial configuration of the facility (NEPIR-0) is financed, in an advanced state of design, and construction will start soon. NEPIR-0 will use a relatively simple low power neutron production beryllium target placed inside the existing shield wall that separates the cyclotron hall from the experimental hall. The facility will be immediately used to test microelectronic components and devices and neutron shielding materials. In the final configuration (NEPIR-1) the capability of the facility will be significantly extended by adding an independent target bunker, two new specialized targets (one of which is high power) and a high power beam dump. In this work, the FLUKA Monte Carlo code is used to study the final NEPIR-1 configuration, in particular the propagation, shielding and absorption of the neutrons generated by the new targets and the beam dump. The code is used to evaluate the activation of the air in the experimental hall and the residual dose due to the activation of the targets and surrounding materials. The methods used are then applied to study the imminent initial configuration of NEPIR, in particular the activation of the Be target, the air and the concrete walls of the experimental hall.