Measurement and Monte Carlo simulation of γ-ray dose rate in high-exposure building materials

Abstract

Natural radioactivity radionuclides in building materials, such as 226Ra, 232Th and 40K, cause indoor exposure due to their gamma-rays. In this research, in a standard dwelling room (5.0 m × 4.0 m × 2.8 m), with the floor covered by various granite stones, was set up to simulate the dose rates from the radionuclides using MCNP4C code. Using samples of granite building products in Iran, activities of the 226Ra, 232Th and 40K were measured at 3.8–94.2, 6.5–172.2 and 556.9–1529.2 Bq kg−1, respectively. The simulated dose rates were 26.31–184.36 nGy h−1, while the measured dose rates were 27.70–204.17 nGy h−1. With the results in good agreement, the simulation is suitable for any kind of dwelling places.