Gas-release measurements and positron beam analysis were performed on amorphized specimens and compared to results on crystalline spinel. The He was released in 2 stages between 575 and 800K in first-order desorption processes with activation enthalpies of 1.9 and 2.7eV and attempt frequencies of about 1013s. The Xe was released between 1050 and 1450K. Positron beam analysis indicated that defect clustering occurred near to the surface at low temperatures and in deeper regions at 950 to 1200K. Recrystallization was observed between 1000 and 1350K and defect annealing was complete at 1600K. Positron beam analysis indicated 2 different damage zones, corresponding to displacement zones with and without Xe.

Helium Behaviour and Defect Evolution in Amorphous Spinel during Thermal Annealing. P.M.G.Damen, A.van Veen, H.Matzke, H.Schut, J.A.Valdez, C.J.Wetteland, K.E.Sickafus: Journal of Nuclear Materials, 2002, 306[2-3], 180-9