Fluorescence lifetime measurements of nano-objects to detect alpha radiation in water

Full description

Objective of the study and challenges: the localization and rapid identification of the source of alpha and beta particle emitted on the surfaces of nuclear installation being dismantled, or to be cleaned up, is a challenge to overcome. The proposed study contributes to developing a concept for remote detection of fluorescence light and its temporal characterization, which will make it possible to attribute the detection to a type of radiation.

Methodology, concept: certain molecules (or nano-objects) in aqueous solution have natural fluorescence under light excitation in the UV-visible range. However, the quantum yields and fluorescence lifetimes of the excited states associated with fluorescence are sensitive to the molecular environment (pH, temperature, solvation, ionic force, electro-magnetic field, etc.). Certain high LET (linear energy transfer) radiation produces very dense ionizations when passing through solution. These typical ionizations of alpha radiation can have an effect on fluorescence lifetimes.

Work required over the duration of the internship: molecules and nanoparticles candidates for forming fluorescent products and sensitive to the density of ionization and radicals produced in tracks at very short times, will be identified by guided bibliography work, then tested and compared by measurements. Spectral measurements and fluorescence lifetimes of the corresponding fluorescent species will be carried out by using the multichannel (16 channels) TCSPC (Time Corelated Single Photon Counting) method in the laboratory on the FLUME laser platform of LIDYL at CEA Orme des Merisiers.

A continuation of the thesis study (in particular using ionizing radiation: beams of protons, particles in general, but also from sealed sources) is possible and financed by the CEA dismantling program.

Location

CEA-Saclay, 91 Essonne, France

Internship conditions

• Internship duration: 6 months
• Level of study: Bac+5
• Training: Master 2
• Continuation in PhD thesis: Yes
• Application deadline: 3 mars 2025

Useful methods and technics:
UV-visible spectroscopy, fluorescence spectroscopy
CSPC (time correlated single photon counting)
Ultrafast Laser Spectroscopy

Computer languages and software:
Microsoft suite

Supervisor

Gérard BALDACCHINO
Phone: +33 1 69 08 57 02
Email :

Head of the laboratory LIDYL / DICO

Gérard Baldacchino
Phone: +33 1 69 08 57 02