Speaker
Description
The nuclear fission is one of the most complex yet fascinating phenomena in nuclear physics. Scientific curiosity regarding the fission process encompasses a broad spectrum of research areas, spanning from fundamental investigations into nuclear structure and dynamics, and nuclear astrophysics to practical applications, such as harnessing nuclear energy, the genesis of medical isotopes for diagnosis and therapy. In this work, we measured the prompt neutrons (PFN) and prompt $\gamma$-rays (PFG) in coincidence with fission fragments emitted from the $^{252}$Cf(sf) source using the ELIGANT-GN detector array setup [1]. This measurement employs an upgraded experimental setup based on our previous measurement [2] with three 16 × 16 double-sided silicon strip detectors (DSSSD) mounted at angles 40$^\circ$, 0$^\circ$, -40$^\circ$ used for the detection of fission fragments. The angular distribution of fast neutrons in the energy range $\sim$ 1 to 10 MeV relative to fission fragments direction (n-f) was determined. The angular distribution is compared with predictions from FREYA model calculations. Both show enhanced yields in forward and backward directions, indicating preferential neutron emission along the fission axis in the fragment direction. Further, neutron velocity density distributions, $\rho(v,\theta$), and neutron-neutron-fragment (n-n-f) correlations are investigated. These observables provide additional constraints on theoretical models. Such models can then be used directly to extrapolate the behavior of neutron rich nuclei in r-process nucleosynthesis calculations, where fission recycling strongly influences the production of the heaviest elements [3].
The authors gratefully acknowledge the financial support provided by the Romanian Ministry of Research, Innovation and Digitalization under Contract PN 23 21 01 06 and by the ELI-RO Program under Contract No. ELI-RO/RDI/2024-007 ELITE.
[1] P.-A. Söderström et al., NIM A 1027,166171 (2022)
[2] S. Dhuri et al., submitted to EPJ Web of conferences
[3] G. Martinez-Pinedo et al., Prog. in Part. and Nucl. Phys. 59, 199 (2007)