Characterization of shaped Bragg crystal assemblies for narrowband x-ray imaging

X-ray imaging using shaped crystals in Bragg reflection is a powerful technique used in high-energy-density physics experiments. The characterization of these crystal assemblies with conventional x-ray sources is very difficult because of the required angular resolution of the order of ∼10 μrad and the narrow bandwidth of the crystal. The 10-J, 1-ps Multi-Terawatt (MTW) laser at the Laboratory for Laser Energetics was used to characterize a set of Bragg crystal assemblies. The small spot size (of the order of 5 μm) and the high power (>10¹⁸ W/cm²) of this laser make it possible to measure the spatial resolution at the intended photon energy. A set of six crystals from two different vendors was checked on MTW, showing an unexpectedly large variation in spatial resolution of up to a factor of 4.