The PADME detector

To search for the production of a dark photon (A') in the process e+e- → A'γ, the PADME apparatus has been built at the INFN Laboratori Nazionali di Frascati. It is a small-scale detector consisting of an active target, a beam monitor system, a spectrometer to measure charged particle momenta in the range 50-400 MeV, a dipole magnet to deflect the primary positron beam out of the spectrometer and allow charged particle momentum analysis and an electromagnetic calorimetric system to detect signal and background photons produced in the annihilations with high accuracy. Each element has specific requirements that are stringent and sometimes at the limit of present technology.