“Cascades begin with a high energy electron, positron, or gamma ray being created in/near the detector.  The simulation of a 80 GeV electron in Lead-Glass at right shows what occurs as the particle passes through the matter. After a short distance the single particle undergoes an interaction which creates other high energy particles.  This continues in an exponentially increasing manner until the particles no longer posses the energy to produce new particles via electron-positron pair production. The shower then gradually thins out as the particles are absorbed by the medium. In the simulation the colors indicate the energy of the particle. Blue/black indicates low energy, red indicates medium energy and yellow indicates high energy. In ice, the length of such an interaction takes place in about 10 m. Note that as the particles move away from the core of the particle shower their energy tends to decrease and their direction becomes less associated the direction of the original particle.  As long as a charged particle remains above the Cherenkov threshold it will emit radiation. This means that the emission profile of a cascade is the super-position of many misaligned Cherenkov cones with a slight preference towards the direction of the Cherenkov cone of the original particle.“
