The X-Ray Diffracting Power of Copper and Iron for Molybdenum and Copper Radiation

Ionization spectrometer measurements were made of the intensity of reflection of the Kα doublet of Mo and Cu from copper and iron powders. From the relative intensities of reflections from the different planes of the powdered crystals, the relative F values for these reflections were calculated. These relative values were placed on an absolute scale by comparison of the intensity of one reflection with that of the (220) reflection of NaCl, for which the absolute value with Mo radiation has been determined by James and Firth. On the assumption that the atomic scattering factors are independent of the wave-length and are proportional to sinθλ, the same absolute value of F was used for the (220) reflection of Cu Kα from NaCl. Because of the difficulty experienced in making plates of the copper and iron powders sufficiently thin for use in absorption measurements, previously determined values of absorption were used in the calculation of the absolute values. Calculated values of the absorption coefficient for NaCl were used.The absolute values of F are shown as functions of sinθλ. Those for copper radiation do not lie on the same curve as those for molybdenum. The fact that the two curves do not coincide suggests that the assumption that F₂₂₀ for NaCl is the same for copper as for molybdenum radiation may not be justified, and that F is not entirely independent of the wave-length.