Use of CR-39 films for nuclear radiation shielding efficacy evaluation of lining materials for combat vehicles

Abstract

All materials provide, to a lesser or greater extent, shielding against nuclear radiations. Armoured fighting vehicles (AFVs) have steel as the structural material, which appears to be a reasonably good gamma and neutron shield material but a shield of pure iron would not be equally effective against whole range of neutron energies as it has a few resonances in electron volt range, and it reduces energy of fast neutrons to lower energy neutrons. These neutrons will be absorbed through radiative capture and emit gamma radiations. Thus it is essential that an effective shield should contain a large amount of moderating material, hydrogen being preferred with low atomic number materials (B, C, Li) and lead (Pb) to ensure that the neutrons do not diffuse at intermediate energies in the shield as well as gamma attenuation will also take place.

In order to have a suitable shield material for armoured vehicles which serves as neutron and gamma radiation attenuator, polyethylene polymer with fillers lining materials are preferred. These materials were evaluated against gamma and fast neutrons using radioactive sources for suitability to fitment into combat vehicle as per the requirement of protection factor values. The detector for gamma radiation was used as Nal(Tl) while for neutron, CR-39 film was used.