Distribution of mass, kinetic energy, and neutron yield in the spontaneous fission ofFm254

Abstract

The mass distribution for spontaneous fission of '"Fm was determined for both preand post-neutronemission fragments. The post-neutron-emission (final) mass distribution was deduced from radiochemical measurements of 24 mass yields. Starting with an assumed distribution of neutron yield versus fragment mass, the pre-neutron-emission (initial) mass distribution and neutron-yield distribution were derived from the kinetic-energy measurements of the fragments and the final-mass distribution by an iterative method. These distributions together with distributions of fragment kinetic energy, total kinetic energy of both fragments, and average kinetic energy and average total kinetic energy as functions of fragment mass are presented. The results are discussed in terms of a scission-point model of fission.NUCLEAR REACTIONS, FISSION +Fm{sf); measured radiochemical mass yields, fragment E; deduced neutron yields, fragment mass and energy distributions.

Characteristics of two fission modes

“…6b; the path leading to the symmetric fission valley has a thicker barrier to penetrate and reaches scission with a less compact shape compared to the one in 258 Fm, and the other path leading to the asymmetric fission valley has a thinner barrier and ends with an elongated scission shape. The result is consistent with the experimental observation of a double-humped asymmetric mass-yield distribution for SF of 254 Fm [21].…”

The Periodic Table Possible Coincided with an Unfolded Shape of Atomic Nuclei

“…This view is also illustrated in Fig. 1 of Unik et al, (1973) (Konecny, Specht, & Weber, 1973), and from 254 100+114+40 Fm c- 4443-4443,b-2222,a-1111 (sf, asymmetric) (Gindler, Flynn, Glendenin, & Sjoblom, 1977) Vol. 9, No.…”

Structure properties ofTh226andFm256,258,Dubray1, Goutte2, Delaroche3 2008Phys. Rev. C119131161View full textAdd to dashboardCite

“…From a theoretical point of view, microscopic self-consistent methods appear to be well suited to study structure effects in fissioning systems, where the sole input is the nucleon-nucleon force. Many studies based on mean field approaches using Gogny or Skyrme forces have recently been devoted to the different fission modes, as for example in 256−258 Fm isotopes [2,3,4,5,6,7], where bimodal fission has been experimentally identified [8,9,10,11,12,13,14,15,16,17] and analyzed [18,19]. Furthermore, two-dimensional timedependent calculations have also been performed for the 238 U isotope in the elongation-asymmetry plane, where it appears that fragment mass and total kinetic energy distributions are well reproduced.…”