''2 theta correction due to displacement of capillary from centre of circle in Debye-Scherrer geometry macro DS_Capillary_SD(x_offset, x_val, y_offset, y_val) { local x_offset x_val local y_offset y_val th2_offset = ((Rad x_offset * Sin(2 Th)) - (Rad y_offset * Cos(2 Th))) / Rs; }