Positron annihilation in radiation chemistry

Hirade, Tetsuya  

There are some advantages of using positrons for radiation chemistry research. One of these is annihilation. A positron annihilates with one of the electrons in condensed materials. The lifetimes of positrons in condensed materials are 100ps to 10ns. Therefore the positron annihilation will provide the information of reactions over these time scales. The second advantage is the bound state of a positron and an electron. It is called positronium (Ps). The formation of Ps is quite similar to the recombination of cations and free electrons. Hence it can provide information on very fast reactions. There have been many interesting researches performed with these advantages. The basic knowledge for positron experiments and some of these researches will be introduced in this chapter.