research papers
A general normal-beam equatorial diffractometer, with no restrictions on the orientations of the goniometer axes, such as collinearity of the axes and , or and , is described. The geometries of this type of unrestricted equatorial normal-beam diffractometer can be unequivocally defined by four angular parameters. Analytical solutions of the goniometer equation and intergeometrical angle transformations, as well as a routine reflection-scan procedure, unaffected by the goniometer offsets, are presented, along with aplications of the unrestricted normal-beam equatorial diffractometer.