DECO is a citizen science project that enables users around the world to detect cosmic rays and other energetic particles with their cell phones and tablets. The recorded events are automatically uploaded to a central database. In addition to detecting particle events, users can analyze the data produced by their own or other users’ phones.
Cosmic rays are energetic subatomic particles produced by powerful cosmic accelerators, such as black holes and exploding stars. When they hit the top of the atmosphere, they produce showers of secondary particles, including electrons, photons, neutrinos, and muons. Many of these muons, which are similar to electrons but heavier, reach the ground at sea level and are a great tool for studying cosmic rays because they are easy to detect.
Digital camera sensors detect muons in much the same way that they detect photons when we take a picture of friends or a landscape. When a cosmic-ray muon hits the camera sensor, it liberates some electrons. The accumulated charge tells us about the amount of energy particle deposited, while the distribution of this charge in our sensor, the shape, tells us about the kind of particle that has produced it.
You can download a guide to get started with DECO here.