Energy Dependence of Defect Production in Displacement Cascades in Silver

Proton damage rates in Ag measured below 10 K show good agreement with calculated defect-production cross sections for low-energy recoils. A substantial decrease in damage efficiency (from $\overline{\xi }=1\mathrm{}$ to $\overline{\xi }\approx 0.6$) occurs as the energy and/or mass of the incident particle increases and displacement cascades are produced. Preliminary results are consistent with cascade efficiencies near $\xi =0.3\mathrm{}$ and an effective transition from $\xi =1\mathrm{}$ to $\xi =0.3\mathrm{}$ centered near recoil energies between 1 and 3 keV.