| This dissertation describes the development of the Gamma Ray Polarimeter Experiment (GRAPE), which is designed to measure the polarization of astronomical sources from 50 keV to 500 keV, and presents the Crab observation results from the successful 2011 balloon campaign. The successful balloon flight of this instrument took place on September 23rd and 24th, at Fort Sumner, New Mexico (Flight N624). The instrument was at float altitude for twenty-six hours. The Crab Nebula/Pulsar, Cygnus X-1, and the Sun were observed within the collimated field of view of GRAPE. A polarization fraction of 55.3% +/- 35.6% and a polarization position angle of 87.8° +/- 28.2° for the off-pulse phase of the Crab was recorded. |
