Characterization of the Qualification Modules with Polarized Gamma-Ray Beams for the biggest Spaceborne Polarimeter POLAR-2

POLAR-2 is a dedicated gamma-ray polarimeter currently foreseen to be launched towards the China Space Station in 2027, based on the success of its predecessor POLAR. It aims to measure the polarization of the Gamma-ray Burst (GRB) prompt emission polarization with unprecedented precision in the 30−800 keV energy range. Thanks to its high sensitivity to the gamma-ray polarization, as well as its large effective area, POLAR-2 will provide a more complete picture for modeling the astrophysical processes responsible for GRBs. The detector consists of a segmented array of plastic scintillator bars, each one of which is read out by a Silicon PhotoMultiplier (SiPM) channel. For this test proposal, 9 qualification modules (whose design passed the space qualification tests) will be used. The goal will be to characterize the detector performance, with polarized gamma-ray beams, including the frontend electronics firmware and data acquisition system.