Natural radiation damage in minerals: What can we learn? - Lutz Nasdala - 12 janvier 2015

Lutz Nasdala, Institut für Mineralogie und Kristallographie,Université de Vienne, Autriche

Lundi 12 janvier 2015 à 10 h 30

IMPMC, Université P. et M. Curie, 4, Place Jussieu, 75005 Paris

Salle de conférence, 4e étage, Tour 22-23, Salle 1

Abstract

The impact of corpuscular radiation, in minerals mainly due to radioactive decays of instable nuclei, may lead to dramatic changes of physical properties and a general decrease in chemical resistance. For instance, results of U–Th–Pb analyses obtained from radiation-damaged samples are hence often biased; the underlying processes hence need to be understood by geochronologists for sound interpretation of results. Another motivation of studying and understanding radiation-damaged minerals is the need to find suitable host forms for the long-term immobilization of nuclear waste. Phenomena of radiation damage in minerals can be studied in various ways, including the investigation of natural species, annealing experiments, syntheses doped with short-lived emitters, irradiation experiments, and mathematical simulations. This lecture focuses at spectroscopic studies of natural minerals and ion-irradiated synthetic analogues. The lecture starts with an introduction to processes of radiation-damage accumulation in natural minerals. Three research examples are presented in detail: (i) Effects of radiation damage on electron back-scattering studied by Raman and photoluminescence hyperspectral imaging. (ii) Effects of radiation damage on the luminescence of minerals (for the examples of natural and ion-irradiated monazite and diamond). (iii) Heavy-ion irradiation of micrometer-thin lamellae prepared using the focused-ion-beam technique.