Biological effects of the Los Alamos meson beam on cells in culture.

Preliminary measurements of the biological effects of negative pions on cells in culture are reported. Cell survival as a function of depth was obtained by using gelatin to suspend the cells. The results indicate that the effects are more pronounced at the peak portion of negative pions. Cell-survival curves were also obtained under oxygenated and hypoxic conditions. The biological effectiveness at the peak was found to be a factor of 2.0 higher than at the plateau. The oxygen enhancement ratio was 1.5 at the peak. No significant differences in biological effects were observed above 14 mm in the peak region.