Effect of vertical divergence on the displacement and breadth of X-ray powder diffraction lines

A treatment is given of the aberrations caused by the extension of the X-ray source, specimen and receiving slit normal to the plane of the camera or spectrometer. A detailed examination is made of the aberrations which occur: ( a ) when the height of the specimen is the sole cause, and ( b ) when the vertical divergence of the X-ray beam is limited by Soller slits, the displacement and profile of the line being determined in each case. It is shown that vertical mis-alinement of a spectrometer can cause an additional broadening of the lines, especially in the back-reflexion region.