Hard X-Ray Polarimetery With Hx-Pol

X-ray polarimetry offers a unique vantage to investigate particle acceleration from compact objects and relativistic outflows. The HX-POL concept uses a combination of Si and Cadmium Zinc Telluride (CZT) detectors to measure the polarization of 50 keV - 500 keV X-rays from cosmic sources through the azimuthal distribution of Compton scattered events. HX-POL would allow us to measure the polarization degrees of Crab-like sources well below 10% for a one day balloon flight. A longer (15-30 day) flight would improve the polarization degree sensitivity to a few percent. In this contribution, we discuss the sensitivity of a space-borne HX-POL payload, and present new results from laboratory tests of the HX-POL Si and CZT detectors.