  In the framework of the Standard Model with lepton mixing the radiative decay
$\nu_i \rightarrow \nu_j \gamma$ of a neutrino of high ($E_\nu \sim 100 \,
GeV$) and super-high ($E_\nu \ge 1 \, TeV$) energy is investigated in the
Coulomb field of a nucleus. Estimates of the decay probability and ``decay
cross-section'' for neutrinos of these energies in the electric field of a
nucleus permit one to discuss the general possibility of carrying out a
neutrino experiment, subject to the condition of availability in the future of
a beam of neutrinos of these high energies. Such an experiment could give
unique information on mixing angles in the lepton sector of the Standard Model
which would be independent of the specific neutrino masses if only the
threshold factor ($1 - m_j^4 / m_i^4$) was not close to zero. (Published in
Phys.Lett.B 323 (1994) 179).
