Alpha-recoil track formation on muscovite and measurement of recoil-range using 252Cf-sources

A Monte-Carlo calculation of the size distribution of latent alpha-recoil tracks in phlogopite: Implications for the recoil-track dating method

“…This presents a problem for the determination of recoil track ages from measurements of surface (zero etch time) track densities ART (0). The likelihood that a fraction of the tracks, in particular, resulting from single decays, is not observed Katcoff, 1969;Hashimoto et al, 1980;Hashemi-Nezhad and Durrani, 1981) presents an equally serious problem. The present calculations show that, in particular, in samples of < 1 Ma, the fraction of tracks below a given threshold size depends again on the age and composition (Th/U-ratio) of the sample and that even for moderate threshold values of the order of a single average recoil range, ART (0) can be underestimated several tens of percent in samples of < 100 ka.…”

“…The relationship between ART and N ART could be complicated by the fact that earlier studies have indicated that all or a fraction (Katcoff, 1969;Hashimoto et al, 1980;Hashemi-Nezhad and Durrani, 1981) of the tracks resulting from a single recoil are not etched. The results of the present calculations show that these tracks make up a variable but in some cases significant part of the recoiltrack population.…”

“…stated that a single alpha decay does not produce an etchable track. Later, Katcoff (1969), Hashimoto et al (1980) and Hashemi-Nezhad and Durrani (1981) concluded that etchable tracks are formed by single alpha recoils with an efficiency of 80% (Katcoff, 1969) or 95% (Hashimoto et al, 1980). Katcoff (1969) observed a relationship between the recoil energy and the density of etched tracks.…”

Annealing behavior of alpha recoil tracks in phlogopite

“…The recoiled nuclei transfer energy to the crystal lattice of the mineral through nuclear collisions, forming a radiation damage zone that becomes observable as alpha recoil tracks (ARTs) (Fig. 1) under an optical microscope after chemical etching (Huang and Walker, 1967;Hashimoto et al, 1981;Hashemi-Nezhad and Durrani, 1981;Gögen and Wagner, 2000). The damage from an individual alpha recoil is much less severe than the massive disruption produced by fission fragments, but overall alpha damage in a mineral is much more extensive due to the large number of alpha decays relative to fission.…”