Use of higher-order reflection from mica crystals in x-ray spectroscopic investigations at 0.1 — 0.3 nm

Crystallographic and dispersion characteristics of mica at high (V — XI) reflection orders were investigated for the first time. Even the order-XI integral reflection was sufficiently strong to be used in experiments. High-precision bending of a mica crystal along a spherical surface with a small radius R = 100 mm and the use of such crystal analysers in focusing spectrographs with one-dimensional and two-dimensional spatial resolution made it possible to record low-intensity spectra of multiply charged ions in laser and Z-pinch plasmas. The method provides exceptional spectral resolution λ/Δλ ≈ 6000 — 10 000 in a wide spectral range (0.15 — 1.8 nm).