Measurements and Interpretation of the Intensity of X-Rays Reflected from Sodium Chloride and Aluminum

Measurements of the intensity of x-rays reflected from sodium chloride have been made by three methods: (1) Reflection from a single crystal, (2) Reflection from a plate of powdered crystals, (3) Reflection from a powdered plate using the transmission method. The results from single and powdered crystal measurements are not in agreement, showing that there is possibly an uncorrected extinction effect in the single crystal measurements. The results from both powdered crystal methods are in very close agreement.Using the Fourier series formula for the electron distribution derived by Compton, electron distribution curves for sodium and chlorine have been obtained. The difference in the electron distribution curves for powdered and single crystals indicates that the absolute intensity measurements must be made accurate to within 1 percent before confidence can be placed in the results. It is also shown that the portion of the experimental curves extrapolated to large angles of reflection is very important.Similar measurements and curves have been obtained for aluminum. The distribution curve and also the F curve are more satisfactory than those obtained for sodium and chlorine, showing that the experimental values for aluminum are probably more accurate than the rock salt measurements.