Radiation Damage and Recovery in Cu, Ag, Au, Ni, and Ta

Abstract

The electric resistivity changes induced by the 12-Mev deuteron bombardment of Cu, Ag, Au, Ni, and Ta foils were determined as functions of the integrated flux. Bombardments were carried out at about -140\ifmmode^\circ\else\textdegree\fi{}C and -150\ifmmode^\circ\else\textdegree\fi{}C, and differences in the two sets of measurements were traced to a thermal recovery process which was proceeding with measurable velocity even at -165\ifmmode^\circ\else\textdegree\fi{}C. This low temperature reaction was characterized by an activation energy of 0.2,\ifmmode\pm\else\textpm\fi{}0.05 ev for Cu, Ag, and Au, and one of 0.3, \ifmmode\pm\else\textpm\fi{}0.1 ev for Ni and Ta. It is suggested that the migration of vacancy pairs offers a reasonable model for the initial recovery process, although other mechanisms are also discussed.