Correlation between Lifetime and Momentum for Positron Annihilations in Teflon

Abstract

A novel technique has made it possible to correlate the three components in the lifetime distribution of positrons in Teflon with the angle between the $\gamma$ rays resulting from the annihilation. The intensity of the intermediate component was found to be virtually independent of this angle, whereas the intensity of the longest-lived component was greatly enhanced for angles corresponding to higher momentum. Apparently the intermediate component does not result from the annihilation of orthopositronium, because the momentum associated with this component is too small. The intermediate component could be caused by free-positron annihilation or by annihilation of positrons which are bound in Teflon molecules.