Gamma-ray bursts are one of the most powerful explosions in the universe and have been detected out to distances of almost 13 billion light years. The exact origin of these energetic explosions is still unknown but the resulting huge release of energy is thought to create a highly relativistic jet of material and a power-law distribution of electrons. There are several theories describing the origin of the prompt GRB emission that currently cannot be distinguished. Measurements of the linear polarization would provide unique and important constraints on the mechanisms thought to drive these powerful explosions. We present the design of a sensitive, and extremely versatile gamma-ray burst polarimeter. The instrument is a photoelectric polarimeter based on a time-projection chamber. The photoelectric time-projection technique combines high sensitivity with broad band-pass and is potentially the most powerful method between 2 and 100 keV where the photoelectric effect is the dominant interaction process. We present measurements of polarized and unpolarized X-rays obtained with a prototype detector and describe the two mission concepts; the Gamma-Ray Burst Polarimeter (GRBP) for the U.S. Naval Academy satellite MidSTAR-2, and the Low Energy Polarimeter (LEP) onboard POET, a broadband polarimetry concept for a small explorer mission.
Digital Object Identifier (DOI)
Joanne E. Hill ; Scott Barthelmy ; J. Kevin Black ; Philip Deines-Jones ; Keith Jahoda ; Takanori Sakamoto ; Philip Kaaret ; Mark L. McConnell ; Peter F. Bloser ; John R. Macri ; Jason S. Legere ; James M. Ryan ; Billy R. Smith, Jr. and Bing Zhang "A burst chasing x-ray polarimeter", Proc. SPIE 6686, UV, X-Ray, and Gamma-Ray Space Instrumentation for Astronomy XV, 66860Y (September 13, 2007); doi:10.1117/12.734403; http://dx.doi.org/10.1117/12.734403
© (2007) COPYRIGHT SPIE--The International Society for Optical Engineering.