Development of the x-ray polarimeter by using pixel-readout µ-PICs (micro pixel chambers)

We developed the new readout system for the pixel-readout μ-PIC (micro pixel chamber), which is one of the micro-pattern gas detectors that have been developed as a X-ray polarimeter so far. By using this system, we succeeded in achieving the sensitivity predicted by the simulation, i.e, the modulation factors, which is one of the most important factors for X-ray polarimeter as defined later in this paper, 0.24±0.08 at 8 keV, 0.18±0.07 at 15 keV in the neon-based gas mixture, and 0.18±0.04 in the argon-based gas although there still remain problems such as the pitch size among pixels and the non-uniformity of the response.