  In the present work we propose to study neutrino oscillations employing
sources of monoenergetic neutrinos following electron capture by the nucleus.
Since the neutrino energy is very low the smaller of the two oscillation
lengths, L23, appearing in this electronic neutrino disappearance experiment
can be so small that the full oscillation can take place inside the detector
and one may determine very accurately the neutrino oscillation parameters.
  Since in this case the oscillation probability is proportional to theta13,
one can measure or set a better limit on the unknown parameter theta13. This is
quite important, since, if this mixing angle vanishes, there is not going to be
CP violation in the leptonic sector. The best way to detect it is by measuring
electron recoils in neutrino-electron scattering. One, however, has to pay the
price that the expected counting rates are very small. Thus one needs a very
intensive neutrino source and a large detector with as low as possible energy
threshold and high energy and position resolution. Both spherical gaseous and
cylindrical liquid detectors are studied. Different source candidates are
considered.
