In the experimental section of this project, the energy spectrum of fast neutrons is measured, after being passed through large blocks, approximately lm3 each, of graphite, aluminium, water and paraffin. Neutrons were produced via 7Li(p,n)7Be reaction by bombarding a Lithium target with 25 or 30 MeV protons of the cyclotron at the Nuclear Research Centre for Agriculture and Medicine in Karaj. Measurements are done using a 76 × 76mm NE-213 scintillator detector, in two points outside the blocks, one in the direction of proton beam and the other normal to it. In analyzing the results of the experiments, SCINFUL and RESPMG computer codes are used to produce the response matrix and the response function of the detector, respectively. FORIST code was, then, used to unfold the neutron spectrum from the pulse height spectrum of proton.   In the theoretical section, the neutron energy spectrum is calculated, in Monte Carlo method, using MCNP-4C code. Finally the results from two sections are compared.


تحت نظارت وف ایرانی