Observations by electron microscopy of tracks of heavy particles in cellulose triacetate

Tracks of heavy charged particles have been observed in cellulose acetate by conventional electron microscopy (100 kV) and by high voltage microscopy (1, 2 MV). The tracks are formed of successive islets following each other at distances of 70 to 150 A. With the evolution of the diameter of these zones is shown the existence of a highly perturbed cylindrical volume (diameter 400 A for the case of krypton) corresponding to regions in which free radicals have been created. The different techniques used do not allow observation of the latent track because of the complications of energetic phenomena: the electron beam current density being limited, the contrast is small and hence the resolution is restricted