DISTRIBUTION OF DAMAGE ALONG AN MEV ION TRACK

It is well known that at low values of dE/dx the damage along the path of an ion in a dielectric solid is not uniform. This distribution of 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 Y3Fe5O12 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 of the process. For such materials the energy loss of the ion is primarily to electronic excitation of the material and is typically in the keV/nm range.