*) The dead time is the period during which the registration channel is closed after detecting the next neutron. There are two kinds of Apatity NM count rate data: with Large dead time (LDT) and Small dead time (SDT). The size of LDT, 1200 microseconds, is chosen so that to block the channel on a lifetime of multiplicity neutrons in the neutron monitor. Thus, at use the LDT to each primary neutron there corresponds one pulse. The result is in a better statistical accuracy of registered count rate of neutrons. Compensation of losses because of dead time is provided with a special electronic circuit. The channel with small dead time, 10 microseconds (same as in the original neutron monitor of Charmichael), collects pulses from all registered neutrons, including ones of multiplicity.