?-irradiation of quenched gold

Abstract
Thin foils of quenched gold containing tetrahedra were irradiated with α-particles of maximum energy of 3·2 MeV to doses in the range 1 to 15 × 1014 cm−2. The foils were examined by electron microscopy before and after irradiation. A fraction, approximately proportional to dose, of the tetrahedra collapsed to form Frank loops; in no case was shrinkage of the tetrahedra observed. The collapse is explained as the radiation-activated collapse of a metastable defect to its stable form. Double tetrahedra also collapsed to form planar loops at a rate twice that for single tetrahedra.