Design and tests of the hard X-ray polarimeter X-Calibur
  X-ray polarimetry promises to give qualitatively new information about high-energy astrophysical sources, such as binary black hole systems, micro-quasars, active galactic nuclei, and gamma-ray bursts. We designed, built and tested a hard X-ray polarimeter X-Calibur to be used in the focal plane of the InFOCuS grazing incidence hard X-ray telescope. X-Calibur combines a low-Z Compton scatterer with a CZT detector assembly to measure the polarization of 10-80 keV X-rays making use of the fact that polarized photons Compton scatter preferentially perpendicular to the electric field orientation. X-Calibur achieves a high detection efficiency of order unity. 
M. Beilicke, M.G. Baring, S. Barthelmy, W.R. Binns, J. Buckley, R.   Cowsik, P. Dowkontt, A. Garson, Q. Guo, Y. Haba, M.H. I...
astro-ph.IM