Polarimetry with a soft X-ray spectrometer - art. no. 701129

An approach for measuring linear X-ray polarization over a broad-band using conventional spectroscopic optics is described. A set of multilayer-coated flats reflect the dispersed X-rays to the instrument detectors. The intensity variation as a, function of energy and position angle is measured to determine three Stokes parameters: L Q and U. By laterally grading the multilayer optics and matching the dispersion of the gratings, one may-take advantage of high multilayer reflectivities and achieve modulation factors over 80% over the entire 0.2 to 0.8 keV hand. A sample design is shown that could be used with a small orbiting mission.