Improving the performance of high-resolution X-ray spectrometers with position-sensitive pixel detectors

A dispersion‐compensation method to remove the cube‐size effect from the resolution function of diced analyzer crystals using a position‐sensitive two‐dimensional pixel detector is presented. For demonstration, a resolution of 23 meV was achieved with a spectrometer based on a 1 m Rowland circle and a diced Si(555) analyzer crystal in a near‐backscattering geometry, with a Bragg angle of 88.5°. In this geometry the spectrometer equipped with a traditional position‐insensitive detector provides a resolution of 190 meV. The dispersion‐compensation method thus allows a substantial increase in the resolving power without any loss of signal intensity.