Avaliação dosimétrica de areia monazítica e de uma rocha de urânio e tório por meio de simulação computacional utilizando o Método Monte Carlo

Abstract

Humans are exposed to different sources of natural radiation. However, due to man-caused factors, this exposure may be above the recommended, and radiological protection measures are necessary for exposed people, together with control/minimization of the radiation source. For this study, the main sources of natural radiation were identified, and a computational simulation was performed using the Monte Carlo Method to determine the dose received by a person exposed to monazitic sand and a uranium and thorium rock. The MCNP 6.2 software was used to perform the simulation. The chemical characteristics of the sand and rock were traced and for the decay series of radionuclides 40K, 232Th and 238U - the main culprits of radiation emission in the employed materials - the highest probability of occurrence and highest amount of emitted energy ones were identified. A radiation source was developed, including the physical space of the laboratory, and two virtual anthropomorphic phantoms representing a woman and a man were added. The data obtained by the simulation were the equivalent and effective dose conversion coefficients. The collected data were evaluated, verifying which organs received the highest dose, and in both cases the breast region presented the highest values for equivalent dose conversion coefficient. The virtual anthropomorphic phantoms exposed to rock had higher radiation doses than those exposed to monazitic sand. It was concluded that using computer simulation to perform a mapping of exposure levels of a given location brings several advantages and possibilities.