We developed an instrument design capable of measuring linear X-ray
polarization over a broad-band using conventional spectroscopic optics. A set
of multilayer-coated flats reflects the dispersed X-rays to the instrument
detectors. The intensity variation with position angle is measured to determine
three Stokes parameters: I, Q, and U -- all as a function of energy. 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 > 50% over the entire 0.2 to 0.8 keV band. This instrument
could be used in a small orbiting mission or scaled up for the International
X-ray Observatory. Laboratory work has begun that would demonstrate the
capabilities of key components.Comment: 6 pages, 3 figures (2 color); to appear in proceedings of "The Coming
of Age of X-ray Polarimetry
