5-9 September 2016
Prague Congress Centre
Europe/Prague timezone

P2.190 Spinel based optical materials for fusion applications

6 Sep 2016, 14:20
1h 40m
Foyer 2A (2nd floor), 3A (3rd floor) (Prague Congress Centre)

Foyer 2A (2nd floor), 3A (3rd floor)

Prague Congress Centre

5. května 65, Prague, Czech Republic
Board: 190
Poster I. Materials Technology P2 Poster session

Speaker

Eduard Feldbach (Institute of Physics)

Description

Radiation tolerant optical components of future fusion reactors have to withstand radiation of unprecedented intensity. It is widely recognized that spinel lattice of AB2O4 double oxides demonstrates enhanced resistance against neutron irradiation. Therefore, the development of spinel optical materials and understanding of their radiation damage processes is of great importance. One defect type of spinel lattice, the so-called antisite defects, needs special attention because these defects influence both, the sintering process and optical properties of resulting ceramics [1]. Antisite formation in AB2O4 spinels means swapping the positions of A and B cations between tetrahedral and octahedral interstices. The deviation from the perfect (normal) spinel structure caused by this swapping is characterized by the inversion parameter i, defined as (A1-iBi)[AiB2-i]O4, where the parentheses refer to the tetrahedral oxygen coordination and square brackets to the octahedral one. The change in i of ~0.1 modifies the lattice parameter by the value that can be determined by XRD, while optical properties are influenced by very low i values, because, for example, in the case of MgAl2O4 spinel the inversion of i=10-3-3 corresponds to antisite concentration of 1.5×101919 cm-3-3. It is a huge amount in terms of material doping, and these antisite defects cause considerable changes in optical properties. In this study, MgAl2O4 optical ceramics and single crystals irradiated with protons or fast neutrons have been investigated. Besides optical absorption, highly sensitive luminescence methods (cathodo- and thermally stimulated luminescence) have been used to reveal the manifestations of antisite defects and to elaborate the criteria for the determination of a low-level inversion in MgAl2O4. [1] N. Mironova-Ulmane et al, Rad. Meas. in press.

Co-authors

Aleksandr Lushchik (Institute of Physics, University of Tartu, Tartu, Estonia) Eduard Feldbach (Institute of Physics, University of Tartu, Tartu, Estonia;LSPM UPR3407 CNRS, Université Paris 13, 99 avenue J-B. Clément, 93430 Villetaneuse, France) Hugo Mandar (Institute of Physics, University of Tartu, Tartu, Estonia) Jevgeni Shablonin (Institute of Physics, University of Tartu, Tartu, Estonia)

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