Abstract
The neutron-induced fission cross section of has been measured from 1 eV to 20 keV using a lead slowing time spectrometer. The cross section was normalized to the (n,f) subthreshold cross section. In the energy region between 1 and 500 eV the fission cross section has a 1/v shape, and has a small peak near 5 keV. By extrapolation of 1/v the thermal fission cross section of 54±6 μb was deduced. The observed 1/v and small-peaked cross sections were interpreted as the fission through the vibrational states in the second well of a triple-humped fission barrier of .
- Received 19 November 1990
DOI:https://doi.org/10.1103/PhysRevC.43.1824
©1991 American Physical Society