Lifetime Spectra of Positrons in ZrO2

Lifetime spectra of positrons for variously prepared ZrO 2 are described essentially by a single parameter, a particle size. A simple model to describe τ 1 , τ 2 , τ 3 , and I 3 is developed. There is a discrepancy between a particle size obtained by an x-ray diffraction pattern and that deduced from a lifetime spectrum for a sample at the initial stage of the crystallization.