Radiation damage in ABO4 minerals

Katja Ruschel
2011 unpublished
This work summarises several individual studies on radiation-damaged ABO4 minerals that address aspects of the quantification of the radiation damage, its effects on material properties, and commonly occurring, subsequent alteration processes. Many natural minerals are characterised by structural damage that results from the radioactive decay of actinides. Such radiation damage is typically associated with property chances, including generally reduced physical stability and increased chemical
more » ... activity. The insights gained are relevant for the Earth sciences as well as the materials sciences. Two individual studies have focused on the ability of light-spectroscopic techniques to characterise the lattice disorder. For monazite–(Ce), a method to distinguish between effects of the chemical composition and the structural disorder on the Raman spectrum was developed. This method will be the indispensable premise for the Raman-spectroscopic estimation of the degree of radiation damage of natural monazite–(Ce). In the case of zircon, the spectroscopic evaluation of the radiation damage is a well-established method that has proved useful in many cases already. In a DAC (diamond anvil cell) study it was verified that the degree of the radiation damage in zircon can be quantified based on spectroscopic parameters even if samples are affected by high pressures. In another study, a natural monazite–(Ce) sample that showed moderate radiation damage but heavy secondary alteration effects, was characterised in detail. It was found that a significant fraction of the thorium was released during the chemical alteration process, and re-deposited in fracture fillings. This leads to a critical assessment of the performance of orthophosphates as potential host materials for the storage of radioactive waste. By contrast, the ability of fergusonite–(Y) for the long-term immobilisation of radionuclides could be supported based on two detailed studies. The highly radiation-damaged fergusonite–(Y) samples investigated showed only a low mo [...]
doi:10.25365/thesis.17044 fatcat:5dwqkjbrrfdenhgbpoymxtnhna