We present a fit of a two-flavor neutrino vacuum oscillation scenario to the GALLEX individual run results. The predicted flux variation during exposure is taken into account for every run. Investigating the published 65 GALLEX solar runs performed during a six-year period we found that parameter sets of $\Delta m^2=5.0\mathrm{}\times {10}^{-10\mathrm{}}{\mathrm{eV}}^2$, ${sin}^{2}2\theta =0.85\mathrm{}$ and $\Delta m^2=9.8\mathrm{}\times {10}^{-10\mathrm{}}{\mathrm{eV}}^2$, ${sin}^{2}2\theta =1.0\mathrm{}$ provide the best fits to the results from both GALLEX data analysis methods. A time-constant suppression is also well compatible with the data. The potential of GNO and BOREXINO in this context is outlined.

• Received 8 February 1999

DOI:https://doi.org/10.1103/PhysRevLett.83.1088