The existence of the positron was verified more than 40 years ago by Anderson but only in the 1950\u27s was much attention given to its usefulness in terms of understanding the electronic structure of solids. As more workers became involved in the 1950\u27s and 1960\u27s work began to appear on metals, gasses and insulators and it was realized that positrons were sensitive to lattice defects. This realization has caused a new burst of interest in experimental and theoretical work using the positron as a probe for defects. Advantages of the positron technique are that it is nondestructive, very fast (106 counts in about 10 minutes), and highly sensitive to very low defect concentrations
