Characterization of the scission point from fission-fragment velocities

TL;DR

This study measures the velocities and isotopic yields of fission fragments from 240Pu and 250Cf to analyze the scission point properties, providing new insights into the fission process at different energies.

Contribution

It introduces a novel experimental approach to directly derive scission configuration properties, including proton- and neutron-number sharing, from inverse kinematics measurements.

Findings

Determined the distance between fragments at scission.

Measured the total kinetic energy and neutron multiplicity.

Analyzed how scission properties vary with fragment atomic number.

Abstract

The isotopic-yield distributions and kinematic properties of fragments produced in transfer-induced fission of 240Pu and fusion-induced fission of 250Cf, with 9 MeV and 45 MeV of excitation energy respectively, were measured in inverse kinematics with the spectrometer VAMOS. The kinematic properties of identified fission fragments allow to derive properties of the scission configuration such as the distance between fragments, the total kinetic energy, the neutron multiplicity, the total excitation energy, and, for the first time, the proton- and neutron-number sharing during the emergence of the fragments. These properties of the scission point are studied as functions of the fragment atomic number. The correlation between these observables, gathered in one single experiment and for two different fissioning systems at different excitation energies, give valuable information for the understanding and modeling of the fission process.