  We propose new nanotargets as nano-layered flat-top cone targets to be used
for future laser-ion acceleration experiments at ELI-NP. We study their
behaviour at the interaction with an ultra-high intensity laser pulse by
performing Particle-In-Cell simulations. We analyze spatio-temporal the
electromagnetic field based on the finite-difference time-domain method for a
complementary description. We find the optimum diameter of the nanospheres and
the proper nano-flat-top foil thickness for which one can obtain monoenergetic
beams of very energetic ions with low angular divergence.
