Investigation of the Absorption of Annihilation Quanta in Solid and Liquid Ga and BiSn Alloy

Absorption of positron annihilation quanta in Ga and Bi$\text{}_{40}$Sn$\text{}_{60}$ alloy in the solid and the liquid phase was investigated. It was found that the mechanism of absorption of annihilation quanta changes on passing from the solid to the liquid state. Results of measurements for Ga and Bi$\text{}_{40}$Sn$\text{}_{60}$ alloy show that for metals changing their density at the melting point the photopeak profiles are modified: their centers of gravity in liquid phase are displaced with respect to those in the solid phase and the number of counts under the photopeak changes, too.