Overview of the detector and its readout on board the imaging x-ray polarimetry explorer

The Imaging X-ray Polarimetry Explorer is the next of the NASA's Small Explorer Missions (SMEX) and it will expand the observation space by simultaneously adding polarization measurements to to energy, time and location. IXPE is comprised of three X-ray telescopes with three X-ray Gas Pixel Detectors (GPD) mounted on the focal plane. The GPD, developed by the IXPE Italian partner (INFN in Pisa together with INAF/IAPS in Rome) is based upon proportional counters with highly pixelated readouts provided by a low noise (∼50 e ^-) CMOS-based ASIC. These detectors operate in a 2-8 keV energy range and it is based on photoelectric effect. Its amplification stage consists on Gas Electron Multiplier (GEM) which allows the detector to make single photoelectron track images. The ASIC has the unique capability of self triggering with automatic ROI selection which allows to have a highly pixelated sensitive area (∼105k pixels, 50 μm pitch), affecting positively the time resolution. These characteristics make the GPD specially suited for astrophysics measurements applications. In this work I will report on the status of the polarimeter and its readout and control electronics.