  X-ray 3D tomography is So far limited to micron resolution because of the
large focusing spot of the focused electron beam on the metal target. Here, we
proposed a nanofocous X-ray 3D tomography system based on focused electrons
from laser-cooled atoms in a nanoscale region of metal target in vacuum useful
for 3D nanotomography and submicron volumetric imaging. We have shown the
system has submicron resolution because of ability of focusing cold electrons
to submicron size, the smaller the X-ray focal spot, the higher the resolution
will be. In our system flux through the specimen of (photons/mm^2/s) can be
improved by sub-micron focusing of X-ray radiation as well. In contrast,
synchrotrons and X-ray tubes provide intense radiation beams, however, these
attributes are not necessary for microtomography and the proposed
sub-microfocus source compares favorably with respect to the radiation flux
because of ability of sub-micron focusing of electrons from near-threshold
photoionizing laser cooled atoms.
