Characterization of the neutron flux distribution at the Athens Tandem Accelerator NCSR “Demokritos”

Quasi-monoenergetic neutron beams, in the energy range 7-11.5 MeV, produced via the 2H(d,n) reaction, have been used at the 5.5 MV tandem T11/25 Accelerator Laboratory of NCSR “Demokritos”. The flux variation of the neutron beam is monitored with a BF3 detector, while the absolute flux is obtained with respect to reference reactions. An investigation of the energy dependence of the neutron fluence has been carried out using two independent techniques: by a liquid scintillator BC501A detector and deconvolution of its recoil energy spectra performed by means of the DIFBAS code, as well as via the multiple foil activation technique in combination with the SULSA unfolding code. The neutron facility has also been characterized by means of Monte Carlo simulations with MCNP5.