title: Hard x-ray spectroscopy and imaging by a reflection zone plate in the presence of astigmatism.
abstract: The feasibility of an off-axis x-ray reflection zone plate to perform wavelength-dispersive spectroscopy, on-axis point focusing, and two-dimensional imaging is demonstrated by means of one and the same diffractive optical element (DOE) at a synchrotron radiation facility. The resolving power varies between 3×101and 4×102in the range of 7.6 keV to 9.0 keV, with its maximum at the design energy of 8.3 keV. This result is verified using an adjustable entrance slit, by which horizontal (H) and vertical (V) focusing to 0.85 μm(H) and 1.29 μm(V) is obtained near the sagittal focal plane of the astigmatic configuration. An angular and axial scan proves an accessible field of view of at least 0.6 arcmin × 0.8 arcmin and a focal depth of ±0.86  mm. Supported by the grating efficiency of around 17.5% and a very short pulse elongation, future precision x-ray fluorescence and absorption studies of transition metals at their K-edge on an ultrashort timescale could benefit from our findings.
authors.forename: Christoph
authors.initials: C
authors.lastname: Braig
authors.forename: Heike
authors.initials: H
authors.lastname: Löchel
authors.forename: Alexander
authors.initials: A
authors.lastname: Firsov
authors.forename: Maria
authors.initials: M
authors.lastname: Brzhezinskaya
authors.forename: Aljosa
authors.initials: A
authors.lastname: Hafner
authors.forename: Jens
authors.initials: J
authors.lastname: Rehanek
authors.forename: Michael
authors.initials: M
authors.lastname: Wojcik
authors.forename: Albert
authors.initials: A
authors.lastname: Macrander
authors.forename: Lahsen
authors.initials: L
authors.lastname: Assoufid
authors.forename: Alexei
authors.initials: A
authors.lastname: Erko