We have measured the internal bremsstrahlung spectrum of the electron capture decay of ${}_{}{}^{71}{}_{}{}^{}\mathrm{Ge}$ in search for a possible mass component of the emitted neutrino. The main relevance of this experiment is given by the collected statistics which is 20 times larger than in a previously published work studying the same decay. Analyses of the data exclude the presence of a massive component of 17.$2_{\mathrm{-}1.1}^{+1.3\mathrm{}}$ keV and (1.6±0.7)% mixing fraction claimed by Zlimen et al. for this same nucleus, at the 99.0% confidence level.

• Received 7 October 1992

DOI:https://doi.org/10.1103/PhysRevC.47.2916