title: Hybrid diamond-silicon angular-dispersive x-ray monochromator with 0.25-meV energy bandwidth and high spectral efficiency.
abstract: We report on the design, implementation, and performance of an x-ray monochromator with ultra-high energy resolution (ΔE/E ≃ 2.7 × 10(-8)) and high spectral efficiency using x rays with photon energies E ≃ 9.13 keV. The operating principle of the monochromator is based on the phenomenon of angular dispersion in Bragg back-diffraction. The optical scheme of the monochromator is a modification of a scheme reported earlier [Shvyd'ko et al., Phys. Rev. A 84, 053823 (2011)], where a collimator/wavelength selector Si crystal was replaced with a 100-μm-thick type IIa diamond crystal. This modification provides a very-small-energy bandwidth ΔE ≃ 0.25 meV, a 3-fold increase in the aperture of the accepted beam, a reduction in the cumulative angular dispersion rate of x rays emanating from the monochromator for better focusing on a sample, a sufficient angular acceptance matching the angular divergence of an undulator source (≈ 10 μrad), and an improved throughput due to low x-ray absorption in the thin diamond crystal. The measured spectral efficiency of the monochromator was ≈ 65% with an aperture of 0.3 × 1 mm(2). The performance parameters of the monochromator are suitable for inelastic x-ray spectroscopy with an absolute energy resolution ΔE < 1 meV.
authors: S
authors: S
authors: Stoupin
authors: Y V
authors: YV
authors: Shvyd'ko
authors: D
authors: D
authors: Shu
authors: V D
authors: VD
authors: Blank
authors: S A
authors: SA
authors: Terentyev
authors: S N
authors: SN
authors: Polyakov
authors: M S
authors: MS
authors: Kuznetsov
authors: I
authors: I
authors: Lemesh
authors: K
authors: K
authors: Mundboth
authors: S P
authors: SP
authors: Collins
authors: J P
authors: JP
authors: Sutter
authors: M
authors: M
authors: Tolkiehn