On the decay of Rb lightest isotopes

β-decay of the lightest isotopes of rubidium 77Rb, 76Rb, 75Rb is studied. Rb isotopes are obtained in the BEMS-2 mass-separator. 50Cr target (thickness is approximately 2 mg/cm2, enrichment approximately 90%) was irradiated by a beam of 32S ions accelerated in the U-300 cyclotron. Detector unit of the mass-separator includes a Ge(Li) spectrometer (volume is 23 cm3, resolution 4.0 keV for 60Co), surface-barrier β-counter and proton detector. Gamma spectrum is obtained for the decay of 77Rb and for 77Kr daughter nucleus. Energies and relative intensities are presented in a table. The results are in good agreement with data of other papers. Half-life of 76Rb β-activity is refined; it is 39.1+-0.6S. Gamma spectrum is presented. A most intensive line 423.5 keV corresponds to the 2+ population. Emission of delayed protons predicted in other papers is not found 75Rb half-life is refined; it makes 17.6+-1.6 S. Within the errors it is in agreement with data of an other paper. In the range of 60-700 keV only one γ-line with the energy of 178.8+-0.5 keV is distinct