Investigation of the effect of temperature on the positron annihilation in solid and liquid tin

The temperature dependence of the counting rate, F ( T ), has been measured in tin. A sudden increase in the counting rate, connected with the creation of vast defects acting as positron traps, has been observed on passing through the melting point. Both the F ( T ) and angular correlation curves indicate that the defected areas decay with increasing temperature. The kinetics of this effect has been discussed and the vacancy formation energy, being equal to E ν = 0.50 ± 0.02 eV, has been determined.