Imaging as a tool for the characterization of the gas pixel detector photoelectric polarimeter

The Gas Pixel Detector (GPD) is an X-ray polarimeter exploiting the photoelectric effect both to measure polarization and to obtain the image of astrophysical sources. This detector is on board the IXPE (Imaging X-ray Polarimetry Explorer) mission selected by NASA in the framework of the Explorer program. We report on the imaging capability of the GPD as a tool to perform a full detector characterization. The analysis of a radiation beam penetrating inclined in the gas cell is discussed showing how this measurement can be used to study different properties of the gas.