Instrumentation for correlated prompt $n$-$\gamma$ emission studies in coincidence with fission fragments

TL;DR

This paper presents a new integrated detection system combining a twin Frisch-gridded ionization chamber and organic scintillators for studying correlated prompt neutron and gamma-ray emissions in coincidence with fission fragments, enhancing fission physics research.

Contribution

The work introduces a compact, optimized detector setup with a novel ionization chamber design for improved measurements of fission fragment properties and correlated radiation.

Findings

Successful assembly of the detector system

First experimental results demonstrating system capabilities

Potential for detailed event-by-event analysis

Abstract

Recent theoretical and experimental results have brought renewed interest and focus on the topic of fission fragment angular momentum. Measurements of neutrons and $\gamma$ rays in coincidence with fission fragments remain the most valuable tool in the exploration of fission physics. To achieve these scientific goals, we have developed a system that combines a state-of-the-art fission fragment detector and $n$-$\gamma$ radiation detectors. A new twin Frisch-gridded ionization chamber has been designed and constructed for use with a spontaneous fission source and an array of forty \textit{trans}-stilbene organic scintillators (FS-3) at Argonne National Laboratory. The new ionization chamber design we present in this work aims at minimizing particle attenuation in the chamber walls, and provides a compact apparatus that can be fit inside existing experimental systems. The ionization chamber is capable of measuring fission fragment masses and kinetic energies, whereas the FS-3 provides neutron and gamma-ray multiplicities and spectra. The details of both detector assembly are presented along with the first experimental results of this setup. Planned event-by-event analysis and future experiments are briefly discussed.