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Measurement of accidental radiation exposure by radio-induced defects in smartphones screens

Contact: OLLIER Nadège, , nadege.ollier@polytechnique.edu, +33 1 69 33 45 18
Summary:
This internship focuses on the identification and characterization of point defects in irradiated glasses mainly by EPR spectroscopy. It includes a glass synthesis part and characterization of defects. One of the aim is to use smartphone screens (Gorilla Glass) as potential "dosimeters" during accidental exposure to radiations.

Internship duration: 4-6 months
Possibility of continuation in PhD: Oui
Deadline for application:27/03/2020

Full description:
Background: In case of a large-scale radiological emergency, methods are needed to identify individuals in the population who have been exposed and require immediate soins ?. There are no operational methods to date. The glasses of smartphones' touch screens keep in "memory" the trace of an irradiation with ionizing radiations by the formation of so-called "radio-induced" defects. The measurement and quantification of these point defects, in particular by electron paramagnetic resonance spectroscopy (EPR), makes it possible to estimate the dose deposited in the glass and thus to estimate the exposure associated with the irradiation. However, an increased understanding of the nature of the stable defects involved and their stability is necessary. Indeed, the nature of the point defects and their properties are not known, moreover they are very dependent on the generation of Gorilla glass (Corning).

Purpose of the internship: During this internship in collaboration with the IRSN (F. Trompier), various spectroscopic techniques (EPR, photoluminescence, and thermoluminescence) will be applied to identify the signature of the main point defects products under gamma radiation. Then we will study their stability, their thermal relaxation and their sensitivity to UV radiation.
The student will work on different types of "Gorilla glass" irradiated with gamma radiation as well as on simplified glasses, close to the glass type "Gorilla glass" that will be synthesized in LSI and that will serve as a model to help the understanding of the processes and the stabilization of radiation-induced defects.
In addition, P2O5-Na2O binary glasses will also be synthesized, irradiated and characterized by EPR to provide experimental data for ab initio calculations (EPR spectra of some point defects). In fact, in the framework of a bilateral CEA-Slovenia project in collaboration with L. Giacomazzi (University of Nova Gorica), we are seeking to identify the nature and processes of formation of point defects associated with the P atom, such as the P3 center.
Technics/methods used during the internship:
RPE - Phototoluminescence - Thermoluminescence

Laboratory
Tutor of the internship

 

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