Ground based measurements

Ground based cosmic ray detectors measure secondary cosmic rays, i.e. the different components produced in air showers in the Earth's atmosphere. The detectors can be divided into subgroups according to the components they measure: nucleonic (protons and neutrons), meson (muons) and electromagnetic (photons, electrons, etc) components. In the following we will discuss the subgroup of ground based detectors known as neutron monitors (NMs)