HX-POL - A Balloon-Borne Hard X-Ray Polarimeter

• Main Authors: Krawczynski, H., Garson, A., Li, Q., Beilicke, M., Dowkontt, P., Wulf, E., Kurfess, J., Novikova, E., De Geronimo, G., Baring, M. G., Harding, A. K., Grindlay, J., Hong, J. S.
• Format: Text
• Language: unknown
• Published: arXiv 2008
• Subjects: Astrophysics astro-ph; FOS Physical sciences; Antarc*; Antarctica
• Online Access: https://dx.doi.org/10.48550/arxiv.0812.1809; https://arxiv.org/abs/0812.1809

We report on the design and estimated performance of a balloon-borne hard X-ray polarimeter called HX-POL. The experiment uses a combination of Si and Cadmium Zinc Telluride detectors to measure the polarization of 50 keV-400 keV X-rays from cosmic sources through the dependence of the angular distribution of Compton scattered photons on the polarization direction. On a one-day balloon flight, HX-POL would allow us to measure the polarization of bright Crab-like sources for polarization degrees well below 10%. On a longer (15-30 day) flight from Australia or Antarctica, HX-POL would be be able to measure the polarization of bright galactic X-ray sources down to polarization degrees of a few percent. Hard X-ray polarization measurements provide unique venues for the study of particle acceleration processes by compact objects and relativistic outflows. In this paper, we discuss the overall instrument design and performance. Furthermore, we present results from laboratory tests of the Si and CZT detectors. : Contribution to the 2008 Nuclear Science Symposium, Medical Imaging Conference and 16th Room Temperature Semiconductor Detector Workshop, 19 - 25 October 2008, Dresden, Germany, Paper R4-6, published in Transactions on Nuclear Science