Ion Explosion Spike Mechanism for Formation of Charged-Particle Tracks in Solids

TLDR

Massive charged particles create intense damage tracks in insulating materials, while in some polymers light projectiles such as α particles also produce tracks. The study proposes an approximate model of an ion explosion spike to explain track formation. The model posits that mutual repulsion of positive ions ejects them into the lattice, forming an ion explosion spike. The tracks arise from a positively charged region created by ionization, the model aligns with diverse experimental data, and in polymers the tracks mainly consist of broken bonds from decaying excited electrons.

Abstract

Massive charged particles create regions of intense damage (tracks) by passing through bulk samples of insulating materials. These tracks are shown to result from the positively charged region created by ionization. An approximate model of an ``ion explosion spike'' is proposed in which the mutual repulsion of the positive ions ejects them into the surrounding lattice. This model is shown to be generally consistent with a wide range of experimental fact. An additional damage mechanism appears to apply to polymers, in some of which tracks are produced by light projectiles such as α particles. The data here are shown to be consistent with tracks consisting primarily of broken bonds caused by decay of directly excited electrons.