Thermal spike analysis of low energy ion tracks

The theoretical track diameter of low energy ions in organic materials is u sually estimated through the model of dose deposition by delta rays, with r esults remarkably lower than the experimental values obtained via a replica method and electron microscopy. The track detector used here is Makrofol-E and the ions studied have specific energies between 1.4 and 100 keV/n. To evaluate the problem from another point of view, thermal effects for track formation, a modified version of the "liquid drop model" for insulators was applied. The electronic as well as nuclear energy deposition by an individ ual ion are considered and the thermal spike evolution is studied. The mode l allows for the formation of ion tracks in a range of energies previously considered as "forbidden". There still exists a discrepancy between the exp erimental data and the track diameters predicted by the model, and although this difference is smaller than the obtained with previous calculations, i t suggests the necessity of further adjustments.