Positron annihilation Lifetime measurements in collagen biopolymer

Lifetime measurement in Positron Annihilation Spectroscopy (PAS) is applied to the study of free-volume collagen characteristics as a function of conc entration. The lifetimes of positrons were measured by a conventional fast- fast coincidence system. All lifetime data are fitted in three components b y using the computer program POSITRON-FIT and resolved. For each concentrat ion, lifetime distributions were analyzed in order to obtain the different components, thus we have observed three components of which one long compon ent tau(3). This long lived component can be associated with a pick-off ann ihilation of ortho-positronium (o-Ps) trapped in free volumes of amorphous region. This investigation shows the potential of positron annihilation spe ctroscopy in the study of biopolymer microstructures.