Performance of the POLAR Gamma-Ray Burst Polarimeter

by Dr Silvio Orsi (University of Geneva)

Wednesday Nov 7, 2012, 3:00 PM → 4:00 PM Pacific/Honolulu

417A (Watanabe Hall)

POLAR is a compact detector that will measure the hard X-ray polarization in the prompt emission of Gamma-Ray Bursts. POLAR consists of 25 modular units, each 1600 low-Z plastic scintillator bars, read out by 25 flat-panel multi-anode photomultipliers. The incoming photons undergo Compton scattering in the bars and produce a modulation pattern; the polarization degree and angle can be retrieved from this pattern with the accuracy necessary for pinning down the GRB mechanisms. In 2009 and in 2011 the response of POLAR to high-energy 100% polarized synchrotron radiation was tested at the European Synchrotron Radiation Facility. During the seminar I will describe in detail the experimental setup for such tests, the data analysis, the results and comparisons with GEANT4 Monte Carlo simulations.