PRELIMINARY-RESULTS OF THE POSITRON-ANNIHILATION IN ZEOLITES - PEAK SHAPE AND 3-GAMMA-DECAY

In many sorts of zeolites long-living positron components are manifest ed, connected presumably with Ps-formation in various kinds of free sp ace in the zeolite structure. Literature values demonstrate, however, a broad scatter of data obtained for assumedly on the same composition of zeolite indicating the possible influence of technology, adsorbate s, impurities, water content, etc. In the present work spectral change s of the 511 keV annihilation peak and its vicinity are evaluated, app lying for the first time a combination of the S and W parameters and t he 3 gamma-specific left plateau region measured in zeolites. To ensur e reproducible experimental conditions, evaluated samples were measure d. The data show individual temperature behaviours of the annihilation parameters in the studied temperature range of 90-450 K for each kind of samples. The temperature dependence becomes reproducible after the first heating run. The results are discussed with respect to the evol ution of long-living positron and positronium components.