Measurement of the o-Ps decay rate using an energy and time spectrometer

A spectrometer for direct positronium annihilation measurements (lifetime as well as energy distribution of annihilation photons) has been built, based on an existing energy spectrometer1 presented by our group. A time branch has been added which allowed us to measure the o-Ps lifetime. We found the decay rate to be 7.0458±0.0279 μs−1.