  The MARS scanner is designed for the x-ray spectroscopic study of samples
with the aid of computer tomography methods. Computer tomography allows the
reconstruction of slices of an investigated sample using a set of shadow
projections obtained for different angles. Projections in the MARS scanner are
produced using a cone x-ray beam geometry. Correct reconstruction in this
scheme requires precise knowledge of several geometrical parameters of a
tomograph, such as displacement of a rotation axis, x-ray source position with
respect to a camera, and camera inclinations. Use of inaccurate parameters
leads to a poor sample reconstruction. Non-ideal positioning of camera, x-ray
source and cylindrical rotating frame (gantry) itself on which these parts are
located, leads to the need for tomograph alignment. In this note we describe
the alignment procedure that was used to get different geometrical corrections
for the reconstruction. Also, several different estimations of the final
spatial resolution for reconstructed images are presented.
