Abstract
Positron lifetimes have been measured in Teflon (P.T.F.E.), polyethylene, nylon-6, polypropylene and paraffin wax. Using equipment of good resolution, W1/2 = 0.7 nsec, wide range, 30 nsec, and a highly linear response, three components of the lifetimes are found in each case. These are about 0.3 nsec, 0 6-1.1 nsec and 1.7-4.1 nsec. Two components only have been reported so far.
A connection is found between the observed intensities of the longer components and the degree of crystallinity of the polymers, and an explanation is offered. The intensities of the long components vary according to the previous heat treatment of the polymer, especially in Teflon, in a way which depends on the physical structure of the solid. The identification of the three components should permit a useful re-examination of positron lifetimes in `molecular materials'.