Subthreshold fission and barrier effects
A review is given of the various ways in which the detailed shape of the fission barrier affects fission probabilities and cross sections. Special emphasis is given to neutron induced fission because of the very good energy resolution obtainable with neutrons, thus allowing investigation of fine details of the reaction mechanism. The narrow intermediate structure observed in (n,f) cross sections is described in some detail, including a discussion of the reaction mechanism and of extracted information on barrier parameters. As an example of the strong vibrational resonances observed in light actinides, data on the resonance in 230Th(n,f) are discussed in the light of the assumed third minimum of the deformation potential for reflection asymmetric deformations. Finally, the effect of symmetries of the nuclear shape at the different saddle points on the absolute magnitude of fission cross sections and on fragment mass distributions are addressed.
Bibliographic Reference: Paper presented: Fifty Years with Nuclear Fission, Gaithersburg, Maryland (US), April 25-28, 1989
Availability: Available from (1) as Paper EN 34722 ORA
Record Number: 198910544 / Last updated on: 1994-12-01
Original language: en
Available languages: en