The BSA modeling for the accelerator-based BNCT facility at INFN LNL for treating shallow skin melanoma

The SPES-BNCT ongoing project of the Istituto Nazionale di Fisica Nucleare (INFN) is aimed at the construction at the Laboratori Nazionali di Legnaro (LNL) of an accelerator-based (AB), high-flux thermal neutron beam facility devoted to boron neutron capture therapy (BNCT) experimental treatment of extended skin melanoma, in the framework of SPES (selective production of exotic species) project. The neutron source will be produced via the (9)Be(p,xn) reactions by a 5 MeV, 30 mA proton beam into a thick beryllium target. The resulting neutron spectrum is slowed down using a beam shaping assembly (BSA), for which modeling is in an advanced neutronic design stage. An overview on the BSA current status, based on the Be neutron converter prototype designed and already constructed, is reported.