Transmission grating efficiencies for wavelengths between 54 Å and 448 Å

Diffraction efficiencies of 44.8-5.4-A x rays by a free-standing gold transmission grating of 1.0-microm period have been measured, using characteristic line radiation. Partial transparency of the grating affects the efficiency at the shorter wavelengths and causes an increase in the efficiencies for orders m>/=1 over the longwavelength values. Model calculations for a trapezoidal wire cross section are in good agreement with the measured efficiencies and allow the wire cross section to be determined. Gratings of this type have a high efficiency for wavelengths as short as 5 A and are, therefore, well suited for applications both in x-ray and extreme uv astronomy.