The independent yields of ${}_{}{}^{101}{}_{}{}^{}\mathrm{Tc}$, ${}_{}{}^{103}{}_{}{}^{}\mathrm{Tc}$, ${}_{}{}^{104}{}_{}{}^{}\mathrm{Tc}$, and ${}_{}{}^{105}{}_{}{}^{}\mathrm{Tc}$ have been determined in the thermal-neutron-induced fission of ${}_{}{}^{239}{}_{}{}^{}\mathrm{Pu}$ using fast radiochemical separation techniques followed by gamma-ray spectrometry. The most probable fragment mass $A_p^{\mathcal{’}}$ and mass dispersion ${\sigma }_A^{\mathcal{’}}$ are obtained from the measured independent yields as 108.35±0.45 and 1.80±0.25 mass units, respectively. A comparison of the elemental yield ($Y_z$) of technetium obtained from the present work and the literature for the thermal-neutron-induced fission of ${}_{}{}^{235}{}_{}{}^{}\mathrm{U}$ and ${}_{}{}^{239}{}_{}{}^{}\mathrm{Pu}$ and the spontaneous fission of ${}_{}{}^{252}{}_{}{}^{}\mathrm{Cf}$ shows that the $Y_z$ of technetium in the case of fission of ${}_{}{}^{240}{}_{}{}^{}\mathrm{Pu}$ and ${}_{}{}^{252}{}_{}{}^{}\mathrm{Cf}$ is very high compared to that of ${}_{}{}^{236}{}_{}{}^{}\mathrm{U}$. The enhancement of the yields in the case of ${}_{}{}^{240}{}_{}{}^{}\mathrm{Pu}$ and ${}_{}{}^{252}{}_{}{}^{}\mathrm{Cf}$ is attributed to the proximity of spherical-deformed neutron shells 82–88 in the complementary fragments antimony and cesium, respectively.

• Received 29 March 1985

DOI:https://doi.org/10.1103/PhysRevC.33.969