  We propose a new method to form very cold neutron (VCN) beams collimated and
monochromatic without usual losses of flux by three or more orders in magnitude
due to narrow line cutting from energy and angular spectra. To this purpose
ultracold neutrons should be accelerated in gravity field to shift their phase
volume in momentum space without volume expansion. The possibilities and
advantages of VCN in studies of nanostructures, the results of modelling of
scattering on various nanoobjects by the real resolution of VCN-diffractometer
are discussed.
