The High-Altitude Water Cherenkov Gamma-Ray Observatory

The Gamma/Hadron Separation Game!

Play this game to see how well you can distinguish events created by gamma rays and cosmic rays in the detector. (See Instructions.)

0/0 gamma-ray showers tagged so far
0/0 proton showers tagged so far

Is this a gamma-ray or a proton event?


A simulated event is shown in the plot. Try to guess whether or not the event was caused by a gamma ray or a cosmic ray. The colors show the relative timing of the hits within the event (blue=early, red=late), and the marker sizes indicate the number of photoelectrons (PEs) in each channel. Large markers mean that a channel was hit by many photons due to a very large ground signal.

To identify cosmic rays, you should look for hard-hit channels far from the reconstructed shower core, which is shown as a blue star in the center of a 40-meter blue circle. Isolated hits indicate the presence of penetrating particles in the shower, a hallmark of cosmic-ray events.

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