Micro-spectoscopy of radiation-damaged minerals

The impact of radioactivity over geologic periods of time may cause intense structural alteration and damages, up to complete amorphization, in certain minerals (such as zircon, ZrSiO4 ). In contrast, other minerals (such as monazite, CePO 4 ) show comparably weak or apparently no notable changes under the same milieu conditions. This is explained by different ratios of two competing processes, namely, accumulation of radiation-induced changes and structural reconstitution. In this project, minerals belonging to both types will be investigated. Samples will be analyzed comprehensively, applying chemical, isotopic, structural, and spectroscopic techniques (preferentially micro-techniques). Experiments are focused on detailed characterization of features of real structure and internal textures of both radiation-damaged and annealed specimens; they will also include annealing experiments and synthesis of doped analogues. These studies aim at improving our knowledge about damage accumulation and damage annealing, with particular consideration of how the ratio between these two processes changes with temperature and from mineral to mineral. The main goal of the project is to contribute to our understanding of causes of the generally decreased chemical resistance of radiation-damaged minerals. This is particularly relevant for geochronology (e.g., interpretation of age determinations based on radioisotopes) and geochemistry/petrology (e.g., alteration of minerals and interpretation of their internal textures). Results will also be of interest for the materials sciences (e.g., performance assessment of host materials for the storage of radioactive waste).

The impact of radioactivity over geologic periods of time may cause intense structural alteration and damages, up to complete amorphization, in certain minerals (such as zircon, ZrSiO4 ). In contrast, other minerals (such as monazite, CePO 4 ) show comparably weak or apparently no notable changes under the same milieu conditions. This is explained by different ratios of two competing processes, namely, accumulation of radiation-induced changes and structural reconstitution. In this project, minerals belonging to both types will be investigated. Samples will be analyzed comprehensively, applying chemical, isotopic, structural, and spectroscopic techniques (preferentially micro-techniques). Experiments are focused on detailed characterization of features of real structure and internal textures of both radiation-damaged and annealed specimens; they will also include annealing experiments and synthesis of doped analogues. These studies aim at improving our knowledge about damage accumulation and damage annealing, with particular consideration of how the ratio between these two processes changes with temperature and from mineral to mineral. The main goal of the project is to contribute to our understanding of causes of the generally decreased chemical resistance of radiation-damaged minerals. This is particularly relevant for geochronology (e.g., interpretation of age determinations based on radioisotopes) and geochemistry/petrology (e.g., alteration of minerals and interpretation of their internal textures). Results will also be of interest for the materials sciences (e.g., performance assessment of host materials for the storage of radioactive waste).