  The goal for future neutrino facilities is the determination of the
$[U_{e3}]$ mixing and CP violation in neutrino oscillations. This will require
precision experiments with a very intense neutrino source. Here a novel method
to create a monochromatic neutrino beam based on the recent discovery of nuclei
that decay fast through electron capture is discussed. The boost of such
radioactive ions will generate a monochromatic directional neutrino beam when
decaying at high energy in a storage ring with long straight sections. We show
that the capacity of such a facility to discover new physics is impressive, so
that the principle of energy dependence in the oscillation probability of the
$\nu_e \to \nu_{\mu}$ channel is operational to separate out the two parameters
of the mixing $\theta_{13}$ and of the CP-violating phase $\delta$.
