Research & Initiatives

Ionizing radiation plays a central role in technological development in several fields. For example, we all enjoy the benefits of radiation, both for diagnosis and radiography and for therapy as a cancer treatment. On the other hand, the world has also witnessed radiation risks in the form of atomic explosions and radiation exposure. Therefore, it is necessary to verify whether the doses absorbed, in environments or by humans, are appropriate for each situation. In addition, it is necessary to develop methods for a quantitative determination of the energy deposited in a given medium by ionizing radiation directly or indirectly, a field of action called dosimetry.

Dosimetric materials are useful for evaluating personal and environmental doses as well as irradiation doses received in medical, spatial, and safety activities. Synthetic dosimeters have the advantage of controlled synthesis and high levels of reproducibility. Particularly, natural dosimeters like minerals find application, e.g., in retrospective dosimetry, geological and archeological dating. Also, natural materials can be a low-cost alternative to synthetic ones and may be more readily available in large quantities.

In general, in Brazil and internationally, the programs for assessing occupational and environmental doses and the various protocols for quality control of equipment have been based on passive solid-state dosimeters. Among these, the luminescent dosimeters stand out. Such dosimeters are composed of radiation-sensitive detector materials, which, after being subjected to a thermal or optical stimulus, emit light with intensity proportional to the radiation dose absorbed by the material. Within this context, as Brazil is one of the largest producers and suppliers of a wide variety of minerals and gems in the world, there is potential in investigating minerals that may be useful for dosimetry. 

The objective of the research is to investigate the effects of ionizing radiation (beta, gamma, and X-rays) and UV light in minerals and other materials using luminescence techniques towards their use as dosimeters. The development of a functional and low-cost radiation detector is one of the goals of this investigation. The potential of materials as a dosimetric material will be investigated by thermoluminescence (TL), radioluminescence (RL), and optically stimulated luminescence (OSL) measurements. TL is the light emitted by some materials upon heating after exposure to ionizing radiation, besides incandescence. OSL is similar to TL but in this case, luminescence is stimulated by the absorption of optical energy instead of thermal energy. Likewise, RL is an important tool for studying luminescence mechanisms. RL corresponds to the luminescence emitted by a material under exposure to ionizing radiation.  The luminescent measurements will be taken in terms of dose-response, repeatability, reproducibility, and signal fading. In addition, materials can be characterized with complementary techniques such as Optical Absorption (UV-Vis) and X-Ray Fluorescence (XRF). It is hoped to identify the defects and investigate the applicability of the Brazilian minerals as a natural dosimeter as well as discovering new materials to obtain future patents.

Finally, the results will bring a great advance in the knowledge of the luminescence of Brazilian minerals and other materials with potential for application in the field of ionizing and non-ionizing radiation dosimetry, such as personal dosimetry, nuclear accident dosimetry, food irradiation control, and luminescence dating. It is envisioned that different materials may have different applications. In addition, this project is an investment in a national resource (minerals) that while little explored in terms of physical properties has great commercial potential.