Like fission-track dating

alpha-recoil track (ART) dating is based on the accumulation of nuclear particles that are released from natural radioactivity and produce etchable tracks in solids. ARTs are formed during the alpha-decay of uranium and thorium as well as of their daughter nuclei. When emitting an alpha-particle

the heavy remaining nucleus recoils 30—40 nm

leaving behind a trail of radiation damage. Through etching the ART tracks become visible with the aid of an interference phase-contrast microscope. Under the presupposition that all tracks are preserved since the formation of a sample their total number is a measure of the sample’s age. The research for etching model is to accurately determine ART volume density

i.e.

the number of ARTs per unit volume. The volume density of many dots in many layers may be determined on a sample using this etching model

and as decreasing the error and increasing the accuracy.