Feasibility studies for imaging e+e− annihilation with modular multi-strip detectors

Studies based on imaging the annihilation of the electron ( e - ) and its antiparticle positron ( e + ) open up several interesting applications in nuclear medicine and fundamental research. The annihilation process involves both the direct conversion of e + e - into photons and the formation of their atomically bound state, the positronium atom (Ps), which can be used as a probe for fundamental studies. With the ability to produce large quantities of Ps, manipulate them in a long-lived Ps states, and image their annihilations after a free fall or after passing through atomic interferometers, this purely leptonic antimatter system can be used to perform inertial sensing studies in view of a direct test of Einstein's equivalence principle. It is envisioned that modular multi -strip detectors can be exploited as potential detection units for this kind of studies. In this work, we report the results of the first feasibility study performed on a e + beamline using two detection modules to evaluate their reconstruction performance and spatial resolution for imaging e + e - annihilations and thus their applicability for gravitational studies of Ps.