Recoil radiation damage in tungsten compounds observed using the Moessbauer effect following Coulomb excitation

The short-time effects of irradiation upon WC, WB, W₂B, W₂B₅, WO₃, and WS₂ were studied by observing the M\"ossbauer effect of tungsten nuclei following Coulomb excitation with 6-MeV α particles. Values for the recoilless fraction, hyperfine interaction, and linewidth were determined in the nonirradiated materials using a tungsten-metal target with tungsten-compound absorbers. These parameters were compared to those obtained by observing the M\"ossbauer effect using tungsten-compound targets and tungsten-metal absorbers. Anomalous hyperfine interactions were observed in all irradiated compounds. The recoilless fraction was found to be reduced in most of the materials. In WO₃ it was found that the fractional reduction in recoilless fraction does not depend on the γ-ray energy and is time independent. The data can be understood in terms of the formation of locally amorphous regions associated with the Coulomb-excited nuclei.