Caracterização física de partículas de radiação através de uma câmara de nuvens de difusão

Abstract

Nuclear radiation is a phenomenon linked to the quantum nature of the processes occurring in the atomic nucleus, which leads to the release of various particles, aiming to bring nuclei to a state of lower energy. The energy scales involved in this process are on the order of 106 eV, so the particle that emerges from the decay carries this magnitude of energy. Due to the diverse applications and risks associated with the interaction of such particles with the environment and living beings, characterizing the emissions of radioactive nuclides is of immense importance. This work sought to build a diffusion cloud chamber, allowing the observation of trails left by the passage of radiation particles through the medium. To arrive at a functional version of the chamber, different arrangements of the apparatus, cooling agents and substances for cloud formation were tested. The radiation sources used in this work were collimated alpha radiation, from americium-241, and beta radiation, from cesium-137. The particle characterization was performed qualitatively through analysis of recorded images of their tracks, which showed significant differences in the energy deposition rates, as well as mass, between alpha and beta particles. Using literature data on the energy deposition rates of these particles in a medium similar to that of the chamber, it was also possible to calculate the initial kinetic energy of the alpha particles, whose frequency distribution for small time intervals resembles that expected for the quantized energy levels of the americium-241 nucleus, with apparent energy loss over the operating time of the apparatus possibly due to the particles’ interactions with the changing chamber environment.