LargE Area burst Polarimeter (LEAP)

S. Gunji, M. McConnell, J. Gaskin, T. Nakamori, S. Kishimoto, T. Mihara, K. Hayashida, H. Takahashi, K. Toma, Y. Kishimoto, Y. Saito, T. Sakamoto, Y. Yatsu, D. Yonetoku, and LEAP Team

To elucidate the radiation mechanism of the gamma-ray bursts through the observation of the gamma-ray polarization, we plan to install the large area burst polarimeter on International Space Station. It is the LEAP. It is constructed by nine identical polarimeters which is called leap polarimeter module (LPM). The LPM consists of 86 pieces of plastic scintillator and 60 pieces of CsI(Tl) which are coupled by each small photomultiplier. It can obtain the information on the polarization utilizing the dependency of the scattering angle on the polarization vector of the incident gamma rays. We had some computer simulations for the LEAP and then investigated the performance. We will present the status of the LEAP and the performance.