  Spectroscopic studies of two beta-rays from 100Mo are shown to be of
potential interest for investigating both the Majorana neutrino mass by
neutrinoless double beta-decay and low energy solar neutrino's by inverse
beta-decay. With a multi-ton 100Mo detector, coincidence studies of correlated
beta-beta from neutrinoless double beta-decay, together with the large Q value,
permit identification of the neutrino-mass term with a sensitivity of ~ 0.03
eV. Correlation studies of the inverse beta and the successive beta-decay of
100Tc, together with the large capture rates for low energy solar neutrino's,
make it possible to detect in realtime individual low energy solar neutrino in
the same detector.
