The P3^3 Experiment: A Positron Source Demonstrator for Future Lepton Colliders

The PSI Positron Production (P$^3$ or P-cubed) experiment is a demonstrator for a e+ source and capture system with potential to improve the state-of-the-art e+ yield by an order of magnitude. The experiment is driven by the FCC-ee injector study and will be hosted in the SwissFEL facility at the Paul Scherrer Institute in Switzerland. This paper is an overview of the P$^3$ design at an advanced stage, with a particular emphasis on a novel e+ capture system and its associated beam dynamics. Additionally, a concept for the experiment diagnostics is presented, as well as the key points of the ongoing installation works