Low-lying levels of ${}_{}{}^{100}{}_{}{}^{}\mathrm{Tc}$ have been investigated with the reaction ${}_{}{}^{100}{}_{}{}^{}\mathrm{Mo}(p,n\gamma ){}_{}{}^{100}{}_{}{}^{}\mathrm{Tc}$ in the energy range $4 \mathrm{MeV}\le E_p\le 6.8 \mathrm{MeV}$. Gamma-ray cascades have been studied by means of $\gamma -\gamma$ coincidences. Two isomeric states have been identified, namely the 200.6 keV ($4^{+}$) state with ${\tau }_m=11.8\mathrm{}\pm 0.1$ μs and the 243.9 keV ($6^{+}$) state with ${\tau }_m=4.7\mathrm{}\pm 0.3$ μs. An upper limit ${\tau }_m\le 4$ ns has been assigned for the mean life of seven other levels.

NUCLEAR REACTIONS ${}_{}{}^{100}{}_{}{}^{}\mathrm{Mo}(p,n\gamma )$, $E_p=4\mathrm{}-6.8$ MeV, pulsed beam; measured $E_{\gamma }$, $\gamma -\gamma$ coincidences, delayed $\gamma$. Two ${}_{}{}^{100}{}_{}{}^{}\mathrm{Tc}$ isomers observed, deduced life-times. Enriched target.

• Received 2 July 1979

DOI:https://doi.org/10.1103/PhysRevC.21.116