Determination of the tenth and half value layer thickness of concretes with different densities

Abstract

Half value layer (HVL) is the most frequently used quantitative factor for describing both the penetrating ability of specific radiations and the penetration through specific objects. The half value layers (HVL) and tenth value layers (TVL) are defined as the thickness of a shield or an absorber that reduces the radiation level by a factor of one-half and one tenth of the initial level, respectively. The concepts of HVL and TVL are widely used in shielding design. They are photon energy dependent, like the attenuation coefficient. HVL and TVL values provide useful information about the penetration of a specific radiation in a specific material. In this study, TVL and HVL thickness are calculated for concretes with different densities. For this purpose five types of concrete with different density ranges were selected, with densities between 600-1500 kg/m3, called lightweight concrete, 1400-2000 kg/m3, called semi lightweight concrete, 2000-2500 kg/m3 called ordinary concrete, 2500-3000 kg/m3, semi heavyweight concrete and 3000-4000 kg/m3 called heavyweight concrete, respectively. For evaluated TVL and HVL thicknesses, the linear attenuation coefficients μ, were determined from measurements, using a collimated beam of gamma rays from a Cobalt-60 source.