An exponential curved crystal: design and performance for high-resolution X-ray spectroscopy

Based on the principles of Bragg diffraction and the Rowland circle geometry, we developed a novel, to the best of our knowledge, curved-crystal spectrometer featuring an exponentially shaped surface. This design facilitates high resolution and high photon collection efficiency over a broad energy range. Crucially, all image points for various X-ray energies lie precisely on the Rowland circle, and the lines connecting these image points to the source point are collinear. The spectrometer achieved a spectral resolution exceeding 18,000 in theoretical and simulation studies, which remained above 3,100 under experimental validation. This innovative and adaptable design offered promising potential for applications in plasma diagnostics and high-energy-density physics research.