Measurement of a Magnetic Field in an Analyzing Magnet of Spectrometer NIS

he main goals of NIS (Nucleon Intrinsic Strangeness) experiment are the search of effects of hidden intrinsic polarized strangeness in nucleon and the search and study of exotic baryons (pentaquarks) in $NN$ reactions. The experiment will be performed at the JINR Nuclotron (Laboratory of High Energies) on the extracted beam with kinetic energy from 1 up to 4 GeV. The electromagnet 1SP-40-4V of the spectrometer has the external sizes 3.20$\times$3.26$\times$4.48 m with aperture of 2.74$\times$0.68 m. Measurement of the magnetic field was carried out with the use of a three-component Hall probe in the online mode. The measured field volume is of 1.03$\times$0.60$\times$3.92 m. The description of the measuring equipment and procedure of measurements are presented. Results of the measurements are given. The results are being used for the Monte-Carlo simulation of the experiment and will be used for analysis of the physical data