Use of proportional counters in X-ray diffraction

IN X-RAY diffraction, the data are obtained by measuring the intensities diffracted at any given angle by a sample. In Fig. 1 is shown a typical experimental arrangement in which the beam from the X-ray tube target is diffracted at an angle 2¿ from its original direction into the measuring device. This device can be moved from 0 to 165 degrees 2¿ by a suitable mechanism as shown in Fig. 2, illustrating a present-day diffraction unit. Then, if the intensity is plotted on a chart as a function of the angle 2¿, a typical diffraction pattern is obtained as shown in Fig. 3. The information directly obtained from this chart concerns the spacing of the atomic planes within the tiny individual crystals present in the sample and the relative (uncorrected) intensities of diffraction associated with those planes. These spacings and intensities can be interpreted to give detailed information about the crystalline characteristics of the sample.