Experimental validation of the neutron transport within a AlF3 and MgF2 neutron moderators for medical applications

At present, the design of a clinical BNCT facility based on a 5 MeV, 30 mA radio frequency quadrupole proton accelerator is underway in Italy, in the frame of the ANTHEM project, and requires an accurate determination of the materials to be used in the Beam Shaping Assembly. The interaction of protons with a beryllium target produces a high flux of neutrons, which are then filtered, moderated and collimated to ensure the desired clinical beam. Here we propose an experimental characterization of Li-containing AlF3, AlF3 and MgF2 moderators at the VESUVIO spectrometer, in order to extensively characterize the neutron transport properties in the moderator and benchmark Monte Carlo simulations. In particular, we plan to use neutron transmission to obtain the total cross section of the moderating material over a wide neutron energy range, from meV to keV energies, together with neutron diffraction and elemental analyses investigation. Finally, deep inelastic neutron scattering will provide a determination of the nuclear kinetic energy of fluorine, which represents a useful parameter in the approximation of thermal scattering laws at thermal-to-epithermal neutron energies in the free-gas model of neutron simulations. Experiments will be performed within the range of operating temperatures, between 373K and room temperature, as well as base temperature, to better assess the importance of zero-point energies.