Catapult neutrons from neck snapping in fission

TL;DR

This study proposes a mechanism where rapid surface healing in fission fragments can produce high-energy neutrons, with simulations indicating a few percent efficiency.

Contribution

It introduces a new dynamical mechanism for neutron emission during fission based on surface healing of fragments.

Findings

High-energy neutrons can be produced by surface healing in fission fragments.

Simulations suggest a neutron emission level of a few percent.

Fragments resemble collinear pear-shaped structures post-scission.

Abstract

Dynamical fission calculations show that the post-scission configurations resemble two collinear pear-shaped fragments whose juxtaposed surface bulges subside relatively quickly, as the fragments acquire smoother shapes. The associated rapid speed of the healing bulge surface may boost nucleons in the fragment to energies sufficient for emission. The present study explores this mechanism by following the fate of nucleons that are reflected off the inwards moving bulge surface. The simulations suggest that the mechanism may produce high-energy neutrons at the level of a few per cent.