The legacy of IXPE: directions towards a new generation of 3D photo-electric x-ray polarimetry missions

IXPE is a mission of great success. It opened a window in X-ray astronomy but it is time to think to the future of this new discipline. IXPE legacy requires larger effective area, better Half Energy Width and larger energy band. New generation of high throughput/high performances X-ray optics are being manufactured making the current IXPE detector design obsolete. IXPE is barely capable to address key scientific cases such as the reflection features in X-ray binaries, from molecular clouds around the Galactic Center and in Radio-Quiet AGNs and imaging of non-thermal emission regions in Supernova Remnants. Polarimetry of jets cyclotron lines in neutron star X-ray binaries and hard tails in magnetars are still inaccessible.To exploit these optics, gaseous detectors with different thickness, pressures and gas mixtures and using ASICs of new generation with parallel readout and simultaneous information on time and charge for each pixel are available allowing for imaging of photoelectron tracks in 3-D. In this talk I will review how the main limitation of IXPE can be solved with current new generation of Gas Detectors discussing possible future X-ray polarimetry mission configurations.