Live stream of Event Display

***** Welcome to the Live Stream of the ALTO prototype events! *****

What you see in the Live Stream are cosmic ray events hitting our gamma-ray detector array prototype at Linnaeus University in Växjö, Sweden. However you see just 3 cosmic ray events per minute, while in reality we record about 200 events per second.

On the right panel you can see the signals detected in the prototype, each colour corresponding to a different detector. Time format is UTC.

The colour green is used to represent the signals seen in the large water Cherenkov detector on the left (Detector 0), while the colour red represents the signals seen in the large water Cherenkov detector on the right (Detector 1). The signals in orange represent those detected in the muon detector below the water tank on the left (Detector 4). The other signals are coming from smaller scintillator detectors located at the top and at the bottom of the water Cherenkov tanks.

You will notice that most of the events are coming from the left water and scintillator tanks, and this is due to the size of the scintillator box, which is larger than the others. We have a trigger logic “two-out-of-eight” meaning that we record the event only if there are two or more detectors “fired” by the cosmic ray. The “triggers” from the left water plus scintillator detectors dominate the event rate, due to the size of the scintillator box.

Most of the events we detect with this trigger condition are solitary muons generated by interactions of cosmic rays, mostly protons, with the nuclei of the atoms composing the atmosphere.