  An investigation on stochastic deflection of high-energy charged particles in
a bent crystal was carried out. In particular, we investigated the deflection
efficiency under axial confinement of both positively and negatively charged
particles as a function of the crystal orientation, the choice of the bending
plane, and of the charge sign. Analytic estimations and numerical simulations
were compared with dedicated experiments at the H4 secondary beam line of SPS
North Area, with 120 GeV/$c$ electrons and positrons. In the work presented in
this article, the optimal orientations of the plane of bending of the crystal,
which allow deflecting the largest number of charged particles using a bent
crystal in axial orientation, were found.
