Measurement of hard cosmic rays in September, 1973 by the Mars-4, Mars-5, Mars-7 automatic interplanetary stations

Characteristics of the equipment and the results of measurements of the intensity of protons, α-particles and nuclei with Z (>=) 15 conducted in September, 1973 are presented. The measurements have been performed by means of gas-discharge counters (Esub(p) > 30 MeV) and the Cherenkov counters (Esub(p) > 500 MeV/nucleon). In the model of spherically symmetric diffusion the course of the increase, which started on September, 7, results in the diffusion coefficient being dependent on distance as kappa=rsup(0.8) for a diffusion path Λ = 0.033 a.u. Since the intensity decrease is governed by N(t) approximately esup(-t/Tsub(0)) law, where Tsub(0) approximately 9 hrs, the diffusion region boundary corresponds to rsub(0) approximately 5 a.u. (usually r0 approximately 2 a.u.). It is possible that the particles from the south hemisphere of the Sun beyond the Earth orbit moved to the North in the region of the automatic interplanetary station location which resulted in the increase of the effective value of r0 by a factor of 2.5. The relation between the amplitudes of particle flux decrease in the space Asub(s) and the Forbush decreases obtained on the basis of data from neutron monitors Asub(nm) is calculated and discussed. With the correlation coefficient being 0.86 +- 0.06 Asub(s) = (1.88+-0.13)Asub(nm)