Fission fragment mass and total kinetic energy distributions of spontaneously fissioning plutonium isotopes

Abstract

Abstract. The fission-fragment mass and total kinetic energy (TKE) distributions are evaluated in a quantum mechanical framework using elongation, mass asymmetry, neck degree of freedom as the relevant collective parameters in the Fourier shape parametrization recently developed by us. The potential energy surfaces (PES) are calculated within the macroscopic-microscopic model based on the Lublin-Strasbourg Drop (LSD), the Yukawa-folded (YF) single-particle potential and a monopole pairing force. The PES are presented and analysed in detail for even-even Plutonium isotopes with A = 236-246. They reveal deep asymmetric valleys. The fission-fragment mass and TKE distributions are obtained from the ground state of a collective Hamiltonian computed within the BornOppenheimer approximation, in the WKB approach by introducing a neck-dependent fission probability. The calculated mass and total kinetic energy distributions are found in good agreement with the data.

Mass Yields of Fission Fragment of Pt to Ra Isotopes

“…The present research is a continuation and extension of our previous works [3][4][5][6]. The fundamental idea of the fission dynamics discussed in this work is that the relatively slow motion towards fission, mainly in q 2 direction, is accompanied by the fast vibrations in the "perpendicular" q 3 and q 4 collective variables.…”

“…The results obtained in Ref. [6] for Pu isotopes have encouraged us to investigate the possibilities of extend-FIG. 3: Potential energy surface cross-sections of 184 Hg on the plane (q3, q4).…”

“…In Ref. [6], the parameter d = 0.15R 0 was adjusted to reproduce the experimental fragment mass yields measured in the low energy fission of 236−244 Pu isotopes. On the other hand, zero-point energy parameter E 0 = 1 MeV related to the q 3 and q 4 degrees of freedom is kept constant.…”

“…The nonadiabatic and dissipative effects in low energy fission were taken into account in a similar way as in Refs. [3][4][5][6]. The potential energy surface (PES) is obtained by the macroscopic-microscopic (mac-mic) method, where the Lublin-Strasbourg Drop (LSD) model [7] has been used for the macroscopic part of the energy, while the microscopic shell and pairing corrections have been evaluated through the Yukawa-folded (YF) single-particle levels [8,9].…”

Deformation Parameters and Collective Temperature Changes in Photofission Mass Yields of Actinides Within the Systematic Statistical Scission Point Model

“…This model has been developed in many branches, such as the Gaussian model [3,4] and modified scission point models [6][7][8][9][10][11][12][13]. The time-dependent model has been significantly developed by Randrup [14][15][16] and others [17][18][19][20][21][22] to predict the shape of mass yields (symmetric or asymmetric modes). Because all of them have sophisticated computations, a systematic method is needed to evaluate the mass distribution of fission fragments in an easy way.…”