EXPERIMENTS ON NUCLEAR-FISSION INDUCED BY RADIOACTIVE BEAMS

The cross sections of Bi-209 nuclear fission induced by secondary beam s of He-6 and He-4 are measured under identical conditions. The experi mental data are in good agreement with earlier results on the fission cross section of the He-4 + Bi-209 reaction. The measured values of th e cross section of Bi-209 fission induced by He-6 ions are much higher than the cross sections of fission induced by alpha-particles. It is found that the fission threshold for the He-6 + Bi-209 reaction is shi fted as compared to that of the He-4 + Bi-209 reaction. Various factor s that can be responsible for the observed peculiarities in the Bi-209 fission induced by the He-6 ions are analyzed.