The spectral widths of the Cu K${\alpha }_1$ and Cu K${\alpha }_2$ x-ray lines have been determined from a series of x-ray diffraction profiles. All profiles were obtained using a two-crystal Ge (111) monochrocollimator and a single (100) GaAs study crystal. The dispersion of the monochrocollimator was determined from the measured separation of the K${\alpha }_1$ and K${\alpha }_2$ peaks. The known dispersion was then utilized to calculate the natural widths of the Cu x-ray lines from the observed diffraction profile widths. The Cu K${\alpha }_1$ and K${\alpha }_2$ lines have full widths at half maximum of 0.000 461(9) and 0.000 61(4) Å, respectively.

• Received 26 August 1987

DOI:https://doi.org/10.1103/PhysRevA.37.2404