  We analyze in the framework of pQCD the properties of the single spin
asymmetry in heavy flavor production by linearly polarized photons. At leading
order, the parallel- perpendicular asymmetry in azimuthal distributions of both
charm and bottom quark is predicted to be about 20% in a wide region of initial
energy. Our analysis shows that the next-to-leading order corrections
practically do not affect the Born predictions for the azimuthal asymmetry at
energies of the fixed target experiments. Both leading and next-to-leading
order predictions for the asymmetry are insensitive to within few percent to
theoretical uncertainties in the QCD input parameters: $m_{Q}$, $\mu_{R}$,
$\mu_{F}$, $\Lambda_{QCD}$ and in the gluon distribution function. We estimate
also nonperturbative contributions to azimuthal distributions due to the gluon
transverse motion in the target and the final quark fragmentation. Our
calculations show that nonperturbative corrections to a $B$-meson azimuthal
asymmetry are negligible. We conclude that measurements of the single spin
asymmetry would provide a good test of pQCD applicability to heavy flavor
production at fixed target energies.
