Orateur
Description
Nuclear fission remains a complex quantum many-body process in which several fundamental properties are not yet fully understood. In particular, the origin of the angular momentum of fission fragments is still under debate. Recent experimental results tentatively probed the angular momentum at scission from the measurement of the spin distributions of fission fragments [1]. Their interpretation as a signature of spin being generated predominantly after scission is highly debated [2], [3].
In this context, we investigate the angular momentum generated in fusion–fission reactions using the system 238U + 9Be $\rightarrow$ 247Cm at an excitation energy of 47 MeV [4]. The experiment was performed using the AGATA $\gamma$-ray tracking array coupled to the VAMOS++ spectrometer [5], providing high-resolution spin distributions from the $\gamma$-ray spectra of isotopically identified fission fragments.
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The present results will be compared with previous measurements at lower excitation energies [6], especially through the observable of the average angular momenta of the reaction partners.
Preliminary results from the analysis will be presented and discussed in this talk.
[1] : J.N. Wilson et al. “Angular momentum generation in nuclear fission.”. Nature (2021).
[2] : J. Randrup and R. Vogt. “Generation of Fragment Angular Momentum in Fission”. Phys. Rev. Lett (2021).
[3] : G. Scamps and G. Bertsch. “Generation, dynamics, and correlations of the fission fragments’ angular momenta”. Phys. Rev. C (2023).
[4] Y.H. Kim et al. “Prompt-delayed γ -ray spectroscopy with AGATA, EXOGAM
and VAMOS++”. Eur. Phys. J. A (2017).
[5] Lemasson, A. et al. “Advancements of gamma-ray spectroscopy of isotopically identified fission fragments with AGATA and VAMOS++”. Eur. Phys. J. A (2023).
[6] A. Francheteau et al. “Excitation energy, angular momentum, and deformation of the 118Pd/134Te neutronless fragmentation in 252Cf(sf)”. Phys. Rev. C (2026).