Isomer shells in the cross section of deep subbarrier photofission of heavy nuclei
Zhuchko V. E. , Ignatyuk A. V., Ostapenko Yu. B., Smirenkin G. N. , Soldatov A. S., Tsipenyuk Yu. M.
For the isotopes 232Th, 237Np, and 238U, in the deep subbarrier region, we observed an abrupt decrease of the slope of the energy dependence of the photofission cross section, called the isomer shelf. An investigation of this phenomenon uncovers a number of new possibilities for the refinement of our concepts concerning the structure of the fission barrier of heavy nuclei.