Positron annihilation in AgBr microcrystals

Abstract

Positron decay rates have been measured in pure silver bromide microcrystals subjected to various surface treatments before and after exposure. Two distinct decay rates are observed in most samples. The results show no difference between the positron decay spectra in microcrystals exposed to uv light relative to unexposed samples, indicating that the chemical transitions induced on the surfaces of silver halide grains by the photographic process are in too low concentration to be detectable by the positron-lifetime technique.