Fission barrier of 209Bi measured by electron induced fission

For ²⁰⁹Bi an electrofission cross section below 10^-36 cm² was measured by the observation of correlated binary fission tracks in mica detectors. From the cross-section data between 28 and 41 MeV electron energy, a fission barrier of 25.5 +/- 1.5 MeV was deduced. The method offers the possibility to measure fission barriers ar low angular momentum and for nuclei not accessible otherwise.