New generation of 3D detectors for X-ray polarimetry: simulation of performances

New generations of 3D gas detectors are today available and applied, e.g., for tracking particles in the vertex detectors of accelerators. They apply the concept of Time Projection Chambers to 2D devices. TimePix3, or the most recent TimePix4, when coupled with a gas system, allows for 3D track reconstruction. Such capability promises to improve by far the sensitivity of the present 2D Gas Pixel Detector (GPD) on board the Imaging X-ray Polarimeter Explorer (IXPE), also solving the issue of its large dead time thanks to its parallel read-out. In this frame, we are developing a simulation software tool based on Geant4 to be used to develop these devices as a new generation of X-ray polarimeters for astrophysics. Moreover, a new read-out software capable of obtaining a 3D track reconstruction, taking advantage of the TimePix3 time capabilities and using the IXPE GPD legacy, has been developed, which helps improve the polarimetric sensitivity in view of future X-ray missions having on board this kind of detectors.