The geometry of etched heavy ion tracks in phlogopite mica; a clear dependence on energy deposited

Abstract

It is shown that the etched track contour geometry in phlogopite mica depends on the extent of the radiation damage present in the track core. At low stopping power values (i.e. low radiation damage), the tracks have triangular (T) geometries while at high damage densities, track contours become polygons which are hexagonal (H) for normally incident fission fragments. For these tracks, the track contour geometry along the track can change from H to T or vice versa due to variations in the extent of radiation damage. Such geometry changes are abrupt and sudden. For fragments with dip angles less than 90°, the track contour geometry can be hexagonal, irregular polygon and triangular. The observed etch figures can be explained on the basis of energy deposited by the heavy ions and thermodynamic quantities of the track-crystal system.