Monte Carlo calculation of shielding parameters for fast neutrons in newly developed heavy concretes

Introduction: The role of radiotherapy as a part of cancer management increases every year around the world. Thus, Radiation protection in the design of radiotherapy rooms are of great importance.   Materials and Methods: In present study using Monte Carlo method, MCNPX code, fourteen types of developed high density concretes with densities ranging from 2.45 to 5.11 g were cm3 simulated and the neutron shielding properties of these heavy concretes with different thickness investigated. The dosimetry parameters were calculated. The neutron shielding performance of the developed heavy concrete samples are tested by using neutron spectra of Am-Be and 18 MeV photon beam of the Varian linac. Some results of simulation were compared with available published results.     Results: The results relate to neutron shielding indicated that chemical compositions, composing elements (heavy elements such as Pb, Fe and light elements including hydrogen) and amount of these elements in concrete have important role in attenuation, capture of neutron and neutron protection.   Conclusion: It was concluded that the elemental composition and hydrogen content contribute an important rule for neutrons attenuation. Therefore when concrete is used for neutrons shielding, the water content as crystallization water in mixing ores must be taken in consideration.