High energy γ-ray detection with the AMS-02 electromagnetic calorimeter

The electromagnetic Calorimeter (ECAL) of the AMS-02 experiment is a fine grained lead-scintillating fibers sampling calorimeter that allows for a precise 3-dimensional imaging of the longitudinal and lateral developement of electromagnetic showers. With a total thickness of 17X0, electromagnetic showers are well contained and the energy resolution is 2% up to 1 TeV. ECAL provides a high discrimination between electromagnetic and hadronic showers; furthermore, together with the rest of the AMS-02 detector, it is able to identify the subdominant (≃10−6) photon flux from GeV up to TeV energies. Thanks to its high granularity ECAL has an excellent pointing capability (0.5o at high energies) that offers an unusual possibility of drawing sky maps with the calorimeter standalone.