Application of a Bonner sphere spectrometer for the determination of the angular neutron energy spectrum of an accelerator-based BNCT facility

•Bonner sphere spectrometer is used to determine the angular neutron energy spectrum of an accelerator-based BNCT facility.•The shadow-cone technique is a method used with Bonner sphere spectrometer to remove the neutron scattered contribution.•The response function matrix for the set of Bonner sphere spectrometer is calculated by Monte Carlo code.•Unfolding codes are used to obtain neutron spectra at different neutron emission angles (0°, 40°, 80° and 120°).

Experimental activities are underway at INFN Legnaro National Laboratories (LNL) (Padua, Italy) and Pisa University aimed at angular-dependent neutron energy spectra measurements produced by the 9Be(p,xn) reaction, under a 5 MeV proton beam. This work has been performed in the framework of INFN TRASCO-BNCT project. Bonner Sphere Spectrometer (BSS), based on 6LiI (Eu) scintillator, was used with the shadow-cone technique. Proper unfolding codes, coupled to BSS response function calculated by Monte Carlo code, were finally used. The main results are reported here.