Distribution of damage along an MeV ion track

It is well known that at low values or dE/dx the damage along the path or an ion in a dielectric solid is not uniform. This distribution or damaged regions versus ion type and energy provides the most direct path to understanding the mechanism that initiates the formation of the damage track. In this report I extract this distribution from recently published data on tracks in Y_3Fe_5O_(12) and compare it with extant data obtained for mica. It is found that these crystalline materials, for which the greatest amount of data exist, provide a virtually identical picture or the process. For such materials the energy loss or the ion is primarily to electronic excitation or the material and is typically in the keV/nm range.