On X-ray polarization splitting with a Baronova-Stepanenko-type crystal

Summary form only given. Polarized X-ray spectra can contain unique information about the anisotropy of plasmas as e.g., produced by picosecond laser pulses. Plasma polarization spectroscopy is particularly difficult on single-shot plasmas because the two polarization directions are traditionally dispersed and polarized separately (by Bragg reflection under 90 degrees), each with its own crystal. These crystals can not be in the same place at the same time, so that the X-rays may come from different parts of the plasma and their polarized spectra can not be directly compared. Recently, Baronova and Stepanenko pointed out that certain crystals, notably quartz, can separate and disperse two linear polarizations at the same time, and they determined some X-ray energies for which this works. The present paper discusses the Baronova-Stepanenko crystal on the basis of well-known physics principles only, viz., geometry for polarization splitting and interference for dispersion. The analysis suggests various other crystals that could become the core of an X-ray spectropolarimeter.