muon Detection
Muons in the atmosphere, a component of cosmic rays
Atmospheric muons are an essential component of cosmic ray showers. When a high energy primary particle coming from space collides with a nucleus of the upper atmosphere, it generates a spray of particles which later interact in their turn. Among these secondary particles are short lived positive or negative pi mesons that decay into positive or negative muons.
The average lifetime of a muon is 2 microseconds (millionth of a second).This 2 microsecond lifetime may seem extremely short, but it is sufficient to allow muons to travel long distances in the atmosphere. Indeed most of the cosmic muons have a high energy and travel at speeds close to 300 000 km / second the speed of light in vacuum.