A mass-spectrometric technique, employing the Chalk River On-Line Isotope Separator at the Chalk River TASCC Facility, has been used to determine the mass ratios between some neutron-deficient isotopes. Two mass doublets ${}_{}{}^{103}{}_{}{}^{}\mathrm{-}_{}^{104}{}_{}{}^{}$In and ${}_{}{}^{104}{}_{}{}^{}\mathrm{-}_{}^{105}{}_{}{}^{}$In and the mass triplet ${}_{}{}^{103}{}_{}{}^{}\mathrm{-}_{}^{104}{}_{}{}^{}$In${\mathrm{-}}^{105}$In have been studied. We have also measured the mass ratio between ${}_{}{}^{72}{}_{}{}^{}\mathrm{Br}$ and ${}_{}{}^{73}{}_{}{}^{}\mathrm{Br}$ to a higher precision than that reported in our earlier work. When combined with the known masses of ${}_{}{}^{103}{}_{}{}^{}\mathrm{In}$, ${}_{}{}^{105}{}_{}{}^{}\mathrm{In}$, and ${}_{}{}^{73}{}_{}{}^{}\mathrm{Br}$ our data yield the atomic mass of ${}_{}{}^{104}{}_{}{}^{}\mathrm{In}$ and improve our earlier value for ${}_{}{}^{72}{}_{}{}^{}\mathrm{Br}$. The measured mass ratios are in good agreement with systematics. Our results for the ${}_{}{}^{104}{}_{}{}^{}\mathrm{In}$ and the ${}_{}{}^{72}{}_{}{}^{}\mathrm{Br}$ masses are 103 918 367 (126) and 71 936 430(294) μu, respectively.

• Received 12 April 1991

DOI:https://doi.org/10.1103/PhysRevC.44.2439