TEM observations on palladium samples aged up to 8 years under tritium.

Transmission electron microscopy (TEM) experiments were carried out on aged under tritium palladium powder samples. The experiments were devoted to the study of the evolution of 3He bubbles (size, density) appearing during aging. The study, using a new sample preparation, was focused for the first time on long aging time, up to 8 years. The TEM results indicated the presence of nanometer size bubbles (2 - 3 nm in diameter) with densities close to 5x10^23 m-3.