  The double beta decays of Mo-100 and Nd-150 were studied in a time projection
chamber located 72 m underground. A 3275 h exposure of a 16.7 g sample of
metallic Mo enriched to 97.4 % in Mo-100 resulted in a two-neutrino half-life
of (6.82 + 0.38 - 0.53 +/- 0.68) * 10**18 y. Similarly, a 6287 h exposure of
15.5 g of Nd2O3 enriched to 91 % in Nd-150 yielded (6.75 + 0.37 - 0.42 +/-
0.68) * 10**18 y. Lower limits on half-lives for neutrinoless decay with and
without majoron emission also have been measured.
