AMS-02 Positron Excess: 2D Charge-Sign Spectrometer

The Alpha Magnetic Spectrometer (AMS-02) has ridden the International Space Station since 2011, sorting cosmic rays by the sign of their electric charge to hunt for antimatter. This 2D simulator rebuilds its core trick as a side-view beam line: a magnetic field bends electrons and positrons in opposite directions, silicon tracker planes read the curvature, and a running Monte Carlo histogram shows how, particle by particle, the measured positron fraction traces out the real anomalous excess — first flagged by PAMELA and confirmed by AMS-02 — that rises unexpectedly above about 10 GeV instead of falling as ordinary cosmic-ray physics predicts. Drag the beam line to pan and use the zoom slider to inspect the curvature near the magnet.