Hybrid detection telescope array
Cosmic ray composition
Extensive air shower
As the cosmic rays' energy increases, the particle frequency decreases sharply. Once at the Earth, the path of the rays experiences less bending in the magnetic field resulting in a deeper penetration into the atmosphere. Particles with intermediate energy levels, called Very High Energy cosmic rays, occur with a frequency of one per square meter per year. The highest energy cosmic rays — levels above 1016 eV — occur at a rate of one per square kilometer per century.