Ar. Lang, THE LATTICE-PARAMETER COMPARATOR - A SYMMETRICAL AXIALLY REVERSIBLE MOUNTING FOR 2 GONIOMETER HEADS, Journal of applied crystallography, 28, 1995, pp. 355-357
A rigid highly symmetrical rectangular frame (physical symmetry m m m)
can carry two goniometer heads coaxially, but opposed apex to apex; t
he frame itself is axially reversible. Used with monochromatized synch
rotron radiation, it permits quick inversion of crystal orientations b
y 180 degrees rotations about the diffraction vector, as is required f
or comparison of lattice parameters in different parts of a single cry
stal or between two separate crystals.