In-situ observation of movement of atoms and identification of thorium atoms by core-loss electron imaging

In-situ observation of the process of coagulation and decomposition of long chain molecules of thorium-pyromeritate dispersed on graphite thin films and their crystallization process to small crystals of ThO2 under electron beam irradiation have been recorded by using the TV system which is located behind the fluorescent screen of JEOL 400 kV electron microscope. Identification of thorium (Th) atoms is carried out using only the electrons having suffered an energy loss corresponding to the excitation of the O4,5 level in Th atoms.