| The objective of this project was the synthesis and densification of lutetium oxyorthosilicate (LSO) powder for the purpose of creating LSO ceramic scintillators. The powders were created using a novel combustion synthesis procedure. Many different alterations to the process, as well as the use of varying precursor materials, were explored in an attempt to lower the amount of resulting impurity phases. It was found that highly pure LSO powders can be synthesized using the combustion method in a furnace at 1000°C with a fuel-to-oxidizer ratio of &phis; = 1.333.;Densification of the powders was attempted by sintering in low pressure (10-1 atm) as well as in an air atmosphere. The low-pressure sintering was done at high temperatures (∼2000°C) and led to good specimen translucency, but all of the silica was lost in the process creating Lu2O3. Subsequent air sintering experiments confirmed that the oxygen pressure helped maintain the silica in the system, but high sintering temperatures could not be obtained because the specimens began deteriorating during the sintering process as the temperature was increased above 1675°C. This deterioration was found to be directly related to the silica content in the material. It is proposed that a sintering atmosphere between that of low pressure and air can balance the reported negative effects and produce high quality LSO compacts for scintillation applications. |
