On the parameters affecting the track opening geometry in biotite mica

Abstract

The bulk etch rate parallel to the cleavage planes of biotite mica increases exponentially with the concentration of the etchant (HF). The track opening shape in biotite can be changed by altering the crystallographic structure of mica by means of external irradiations prior to the irradiation of the sample with fission fragments or heavy ions. For alpha particles and electron doses of greater than 3 × 10 8 Gy the openings of the normally incident fission tracks become circular, as compared with the hexagonal track openings in unirradiated samples. It is shown that the track opening geometry also depends on the amount of radiation damage present in the track core.