Teste | Abstract: 93-1 | ||||
Abstract:Gamma radiation is a highly penetrating form of ionizing radiation that plays a fundamental role in various fields such as medicine, industry, and scientific research. Originating from the radioactive decay of unstable atomic nuclei, gamma radiation consists of high-energy photons capable of penetrating solid materials and deeply interacting with living matter. Due to its high energy and penetrating capability, measuring gamma radiation is a complex task that requires specific equipment and sophisticated techniques. Thermoluminescent dosimeters (TLDs) can measure the absorbed dose to which materials or individuals have been exposed. The One Trap One Recombination (OTOR) model can describe these detectors' operating principles. After being exposed to ionizing radiation, they store energy due to the interaction of radiation photons with the material by means of electron-trapping processes. When heated the electrons are released and they release the energy excess in the form of light. The amount of light emitted is proportional to the absorbed radiation dose, allowing for precise measurement. Due to their sensitivity and precision, TL dosimeters are essential for monitoring radiation exposure in various applications. Radiometric characterization of environments, such as irradiation chambers used in laboratories, is crucial to ensure accuracy and safety in gamma radiation applications. This process includes determining essential parameters such as absorbed dose and absorbed dose rate. The absorbed dose refers to the amount of energy deposited by radiation in a unit mass of material, while the absorbed dose rate is the absorbed dose per unit of time. In this study, calibrated and traceable thermoluminescent dosimeters were used to quantify and analyze the absorbed dose values in the labyrinth of an irradiation chamber. These dosimeters were analyzed using specific equipment to read and obtain the absorbed dose values. Dosimeter calibration was carried out according to international standards, ensuring traceability and measurement accuracy. The results showed that the absorbed dose values and absorbed dose rate decreased with increasing distance from the irradiation chamber. This behavior was expected since gamma radiation interacts with the labyrinth walls through Compton scattering, a process in which radiation photons collide with electrons in the walls, losing part of their energy with each interaction. As a result, the photons' energy decreases as they move away from the radiation source, leading to a reduction in the absorbed dose. Quantifying the absorbed dose in irradiation environments is fundamental to ensuring the safety and effectiveness of gamma radiation applications. The use of thermoluminescent dosimeters allows for precise and reliable measurements, essential for the radiometric characterization of irradiation chambers. The results of this study confirm that the absorbed dose and absorbed dose rate decrease with distance due to Compton scattering occurring in the walls of the labyrinth of the Gamma Irradiation Laboratory (LIG). Keywords: Dosimetry, thermoluminescent, Dosimetric characterization, Industrial Irradiator |