1. Registration of neutrinos at the Earth's surface.
Basic problem with the registration of neutrinos of cosmic rays at the Earth's surface is a very high background of atmospheric muons, which 20 billion times exceeds the expected flux of muons from neutrino interactions. The criteria of determining the direction of particle motion were developed for the quasi-spherical modules, and the rejection factor for particles, moving in opposite directions was evaluated; for one QSM it is equal to 20.
In order to achieve the rejection factor 2õ1010 it is necessary that not less than 8 QSM would correctly indicate the direction of particle motion. Two neutrino events were found in the analysis of events from the bottom hemisphere, in which zenith angle exceeded 135. Thus, the possibility of registering the neutrinos at the Earth's surface was proven.
2. Remote monitoring of solar and atmospheric processes.
The disturbances of muon flux at the Earth's surface can be caused by different processes, proceeding as on the Sun, so in the upper atmosphere. In contrast to neutron monitors widely used for these purposes, which are capable of recording only a certain integral effect of the disturbances of cosmic radiation, muon hodoscope gives the spatial and temporal picture of the phenomenon. Operative analysis of these disturbances makes it possible to trace the motion of air masses in the atmosphere (for example, hurricanes) and to predict the time of their appearance at a particular point.
3. Muon showers in horizontal flux of the cosmic rays.
Practically all installations for registering the extensive air showers are located horizontally and cannot effectively record showers at large zenith angles. At the same time, the structure of showers and the composition of shower particles rapidly change with increase of zenith angle, they become purely muon showers, and their lateral sizes increase many times. This circumstance makes it possible to record with the NEVOD-DECOR installation the muon showers generated by primary particles with energy 1017 and even 1018 eV at angles more than 70°.