Visible optical spectra of [MATH]-irradiated uranium - doped ZBLAN fibres

Actinides, particularly uranium, are again of interest because these elements provide a broad spectroscopic tunability and open a new field of fibre laser applications. The uranium ion possesses many oxidation states, the most stable being U4+ and U6+. U3+ is an unusual oxidation state in fluorides. U3+ is of interest because it can provide an efficient laser emission of between 2 and 2.7 µm. We report visible absorption and fluorescence spectra of pure and γ-irradiated uranium - doped ZBLAN fibres. We show that γirradiation leads to a high reduction of U4+ into U3+, which is stable over a few years. Strong absorption bands of U4+ and U3+, centered at 650 nm and 860 nm respectively, enable us to estimate the change of the uranium oxidation state

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Carte Echelle 1/50 000 (48°40'N), Ifremer, Issy-les-Moulineaux

Multi-scale morphologic variability of the North Fiji Basin ridge (Southwest Pacific)

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Imaging exhumed lower continental crust in the distal Jequitinhonha basin, Brazil

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