  We calculate, within the pseudopotential approximation, a one-dimensional
scattering amplitude and effective one-dimensional interaction potential for
atoms confined transversally by an atom waveguide or highly elongated
``cigar''-shaped atomic trap. We show that in the low-energy scattering regime,
the scattering process degenerates to a total reflection suggesting an
experimental realization of a famous model in theoretical physics - a
one-dimensional gas of impenetrable bosons (``Tonks'' gas). We give an estimate
for suitable experimental parameters for alkali atoms confined in waveguides.
