No evidence for the neutrinoless double-$\beta$ decay of ${}^{100}$Mo has been found in a search using a segmented Si(Li) detector with source foils enriched to 97% ${}^{100}$Mo. From an exposure of 0.2664 mole years, and using Bayesian statistics to calculate confidence levels, we find a 68% lower limit on the half-life for the $J^p{=0\mathrm{}}^{+}\to 0^{+}$ transition of $0.22\times {10}^{23}$ yr. The measured half-life of the two neutrino double-$\beta$ decay is ${0.76}_{-0.14}^{+0.22\mathrm{}}\times {10}^{19}$ yr.

• Received 24 April 1996

DOI:https://doi.org/10.1103/PhysRevC.55.474