ИСТИНА

A fast registration system for a neutron monitor (NM) is developed in PGI. It records to a file time of neutron coming into NM with accuracy 1 mcs. The number of NM tube is fixed too. So the output data consist of exact time and generation place each of billion pulses of NM. The system is set on a row of NMs (Spitsbergen, Apatity, Moscow and Northern Caucasus). It is used in studying of multiplicity in NM and other short-time effects. Under a processing of data by the separating it is possible to modify conventional NM to a device of different design, i.e. creating virtual NMs according to a task. Without NM stopping, moving or breaking different design NM is possible. There were developed a row of virtual NMs with different distance between tubes (from a one omitted tube up to 15 tubes). Undraw function (dependence on spacing) was carried out. With increase of spacing between operating tubes pulse coincidence falls down firstly than becomes constant till spacing of 15 tubes. There were detected events of large number coincidence, i.e. multiplicity in NM. All events were checked on interference origin. These events could be produced by a nucleon atmospheric showers. The size and structure of the showers are carried out too.