Imaging X-ray crystal spectrometer for laser-produced plasmas

X-ray Thomson scattering (XRTS) is a powerful technique for measuring state variables in dense plasmas. In this paper, we report on the development of a one-dimensional imaging spectrometer for use in characterizing spatially nonuniform, dense plasmas using XRTS. Diffraction of scattered x-rays from a toroidally curved crystal images along a one-dimensional spatial profile while simultaneously spectrally resolving along the other. An imaging spectrometer was fielded at the Trident laser at Los Alamos National Laboratory, yielding a FWHM spatial resolution of < 25 μm, spectral resolution of 4 eV, spectral range of 350 eV, and spatial range of > 3 mm. A geometrical analysis is performed yielding a simple analytical expression for the throughput of the imaging spectrometer scheme. The SHADOW code is used to perform a ray tracing analysis on the spectrometer fielded at the Trident Laser Facility understand the alignment tolerances on the spatial and spectral resolutions. The analytical expression for the throughput was found to agree well with the results from the ray tracing.