Dynamic evolutions of swift heavy ion induced latent tracks under electron bombardment from TEM

Dynamic evolutions of morphology and size of swift heavy ion (SHI) induced latent tracks in muscovite mica were explored using in situ transmission electron microscopy (TEM) in this paper. Prior to the measurements, muscovite mica sheets were irradiated with Kr and Bi ions with electronic energy loss (dE/dx)e of 5.9 keV/nm and 31.5 keV/nm, respectively. It is observed in TEM micrographs that the latent tracks in mica are continuously along the cross section view of the ion tracks. The track profile is not found dramatically uniform but rather it is found slightly fluctuating for similar (dE/dx)e values. In situ TEM observation clarify that atoms in the track halo are unstable compared with the lattice atoms in the vicinity of the track. Point defects induced by the electron bombardment are generated preferentially around the track core, which results in the increased diameter of the track.