Effects of ionizing radiations on the optical properties of ionic copper-activated sol-gel silica glasses

International audienceStudying the impact of radiations on doped silica glasses is essential for several technological applications. Herein, bulk silica glasses, activated with various concentrations of luminescent monovalent copper (Cu+), have been prepared using the sol-gel technique. Thereafter, these glasses were subjected to X- or γ−rays irradiation at 1 MGy(SiO2) accumulated dose. The effect of these ionizing radiations on the optical properties of these glasses, as a function of the Cu-doping content, were investigated using optical absorption and photoluminescence spectroscopies. Before any irradiation, the glass with the lowest copper concentration exhibits blue and green luminescence bands under UV excitation, suggesting that Cu+ ions occupy both cubic and tetragonal symmetry sites. However, at higher Cu-doping level, only the green emission band exists. Moreover, we showed that the hydroxyl content decreases with increasing copper doping concentration. Both X and γ radiation exposures induced visible absorption due to HC1 color centers in the highly Cu-doped glasses. In the case of the lower Cu-doped glass, the Cu+ sites with a cubic symmetry are transformed into sites with tetragonal symmetry

Verre de silice sol-gel dopé Cérium pour une dosimétrie fibrée de radiations ionisantes

International audienc

Investigation of TSL properties of potential fibered-OSL dosimeter materials

International audienc

Low Dose and Low Dose rate measurements of X-rays using Copper-doped Sol-gel Silica Glass

OralInternational audienc

X-ray Monitoring using Optically Stimulated Luminescence in Cerium-doped Sol-gel Silica Glasses

International audienc

Cerium-activated sol–gel silica glasses for radiation dosimetry in harsh environment

International audienceCerium-doped silica glass has been prepared for ionizing radiation dosimetry applications, using the sol–gel route and densification under different atmospheres. In comparison with the glass densified under air atmosphere, the one obtained after sintering the xerogel under helium gas presents improved optical properties, with an enhancement of the photoluminescence quantum yield up to 33%, which is attributed to a higher Ce3+ ions concentration. Such a glassy rod has been jacketed in a quartz tube and then drawn at high temperature to a cane, which has been used as active material in a fibered remote x-ray radiation dosimeter. The sample exhibited a reversible linear radioluminescence intensity response versus the dose rate up to 30 Gy s−1. These results confirm the potentialities of this material for in vivo or high rate dose remote dosimetry measurements

Doped sol–gel silica glasses for radiation dosimetry in harsh environment

InvitéInternational audienc

Sol–gel silica glasses for radiation dosimetry

PosterInternational audienceIn the field of new techniques for radiotherapy, also in harsh environment such as in nuclear facilities or in space industry, ionizing radiation dosimetry requires monitoring over long distances and/or with high space resolution of the measurement. For these applications, fibered solutions seem particularly adapted, but in this domain, new sensitive materials, able to be drawn into fibers, are needed. Indeed, scintillating fibers already exist, generally made of tissue-equivalent organic materials, which are particularly interesting to remotely measure real-time X-ray doses in radiotherapy applications. However, these plastic optical fibers exhibit rather poor guiding properties and could suffer from radiation in hostile environment. Thereby, increased attenuation losses and degradation of the scintillating dopant may occur in those devices when exposed to high dose rates, which is a problem in nuclear industry where radiation hardening of the safety or radioprotection devices is a crucial point. Inorganic radio-sensitive optical elements, like doped silicate glasses, can overcome these drawbacks. Moreover, compared to their crystalline counterpart, the glassy scintillators show higher mechanical and thermal stabilities, facilitating their shaping as optical fibers. Hence, this presentation will focus on the potentialities of doped sol-gel silica glasses for in-vivo / in-situ or high dose rate remote measurements.This work deals with the spectroscopic and optical properties of a bulk cerium-doped sol–gel vitreous glass, obtained by densification either in air or in helium atmosphere. In comparison with the glass densified under air atmosphere, the one obtained after sintering the xerogel under helium gas presents improved optical properties, with an enhancement of the photoluminescence quantum yield up to 33 %, which is attributed to a higher Ce3+ ions concentration. The second kind of samples are sol-gel silica glasses activated with various concentrations of Cu+ ions. Here again, we show that the densification atmosphere has a decisive impact on the visible luminescence performance of the glass. The exposition of these Cu-doped samples to high doses of X-ray or -radiation induces point defects, a visible darkening and a strong reduction of their photoluminescence quantum yield. However, the materials remain optically active and can be used in a dosimetry setup.Such glassy cylindrical samples have been drawn at high temperature into thin canes, pieces of which have been used as active materials in fibered remote X-ray radiation dosimeters. The samples exhibited a reversible linear radioluminescence intensity response versus the dose rate up to 50 Gy s−1. The optically stimulated luminescence properties of these doped silica rods have also been investigated using the same fibered setup. These results confirm the potentialities of such materials for in- vivo / in-situ or high dose rate remote dosimetry measurements

Projet SURFIN : nouveaux matériaux pour la SURveillance par Fibre optique des Installations Nucléaires

International audienc