2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/39567A detailed study of the solar neutrino vacuum oscillation was made taking into account three neutrino flavours and the seasonal effect. This analysis was established for a range of the mixing parameter sin^2(2ϕ), that is concerned with the electron-tau neutrino oscillations, from 0 to 1. We obtained the allowed mass regions versus mixing angles by fitting only the rates of the five solar neutrino detectors in activity and we compared with the fits including the recoil-electron spectrum of the Kamiokande and Super-Kamiokande experiments. The averaged survival probabilities for electron neutrinos as a function of the neutrino energy are also obtained, showing that the solutions for sin^2(2ϕ) greater than 0.50 with the maximum exclusion of Be7 neutrinos and the minimum exclusion of pp neutrinos give a better explanation for the suppression rates of all detectors.11 pages, 5 .ps figures, some modifications on the tables and figures with better definitionHigh Energy Physics - Phenomenologytext