The goal of this project is to test the performance of the novel chalcogenide glass (ChG) phase change temperature sensors under irradiation. This study will reveal the impact of ion irradiation induced defects on device architecture, optical and electrical properties of chalcogenide glass in both amorphous and crystalline phases. Phase change chalcogenide glasses crystallize at certain temperatures, which is dependent on the composition. Changing of phase also changes the optical and electrical properties of the materials. To utilize this phenomenon, from the vast number of chalcogenide glasses, Ge-Se and Ge-S systems have been studied extensively for temperature sensing purpose in high radiation environment. These sensors are typically suitable for the monitoring of components with temperatures up to 500°C, although with specific adjustment of the composition of the material this sensor can become useful for metallic or ceramic SFR reactors where the cladding temperature can reach 650°C. This will provide a measurement method for multiple components in the reactor design domain of multiple reactors. The amorphous phase of ChG can be reversed by application of an electric field, thus facilitating multiple time use of the sensors. Besides, getting knowledge about the performance of the radiation hard waveguides in the reactor environment could extend their application to much more important characterization methods like for light transmission for in situ in-pile Raman spectroscopy. This experiment involves ion irradiation at different temperatures, optical, electrical characterization and transmission electron microscopy to study the effect of interfacial defects on device performance. This will provide crucial data about how the irradiation changes the optical and electrical properties of the material in both amorphous and crystalline phases. Although the amorphous phase under irradiation has been studied widely, not enough data is available for their crystalline phase. Upon satisfactory completion of the experiment, optical and electrical properties of a library of chalcogenide glasses in both phases will be obtained. It will help to understand certain device failure criteria and how the devices are going to perform when structural defects occur.