Luminescent defects induced by sintering of silica nanoparticles

Luminescence properties induced by sintering of silica nanoparticles

The effect of sintering on the optical properties of silica nanoparticles, a mean diameter of ~14 nm, are investigated by absorption and luminescence experiments. The sintering is induced by a thermal treatment of 1000 °C for 272 hours; after that the sample is transparent, and emits a bright luminescence under UV excitation. Time resolved photoluminescence spectra excited by a tunable laser source allows to evidence four bands around 2.0 eV, 2.4 eV, 2.7 eV and 3.4 eV, peculiar to defects induced by the sintering.

Radiation and Hydrogen-Loading effects on Raman fiber-based temperature sensors

We present experimental studies on how Raman based temperature sensors undergone two different treatments: gamma-radiation and H-loading. Unfortunately, gamma radiation and hydrogen release in harsh nuclear environment can affect the temperature measurements based on this technology of sensor, limiting the sensor performances. Moreover, the Raman device response in both cases changes with the different classes of multimode fibers that are used by the engineers.