Speaker
Description
Prompt and delayed gamma ray spectroscopy of nuclear reactions inducing fission can reveal a wealth of important information. Gamma ray spectroscopy of the de-exciting fragments after fission occurs not only allows study of the nuclear structure of neutron-rich nuclei, but also provides essential information on the fission process itself [1][2]. Conversely, study of delayed gamma emission can be used to extract isomeric yield ratios [3] and probe rare phenomena such as the population and back-decay of the fission shape isomers – metastable states with very large deformations which sit on the pathway to fission [4].
This presentation will give an overview of recent results on the gamma ray spectroscopy of fission with the nu-Ball2 spectrometer [5] at the ALTO facility of IJC Lab. Several open questions are currently being addressed, such as the evolution of fragment yield distributions in the sub-actinide region [6], the emission of high energy gamma rays in nuclear fission with potential population of collective excitations (PDR, GDR, etc.) in the emerging fragments [7]. The experiments have also explored other outstanding questions, such as the angular momentum carried away by neutron emission [8] and angular correlations between the spins of fission fragment partners and measurements of angular distributions of gamma rays with respect to the fission axis [9][10][11]. An overview of these new studies from the ν-Ball2 experimental campaign will be given and selected results will be presented along with future perspectives.
References
[1] S. Leoni, B. Fornal, N. Mărginean and J.N. Wilson, Eur. Phys. J. Spec. Top. 233, 1061–1074 (2024)
[2] J.N. Wilson et al., Nature 590, p566–570 (2021)
[3] D. Gjestvang, J.N. Wilson et al. Phys. Rev. C 108, 064602 (2023)
[4] C. Hiver, J.N. Wilson et al., Acta Physica Polonica, Proceedings of the Zakopane Conference on Nuclear Physics, Vol. 18 (2025)
[5] G. Pasqualato and J.N. Wilson, Nuclear Physics News, 34 16-20, (2024)
[6] K. Miernik et al. Phys. Rev. C 108, 054608 (2023)
[7] H. Makii et al. Phys. Rev. C 100, (2019) 044610
[8] I. Stetcu et al., Phys. Rev. Lett. 127, 222502 (2021)
[9] J. Randrup, Phys. Rev. C 106, L051601 (2022)
[10] A. Bulgac et al., Phys. Rev. Lett. 128, 022501 (2022)
[11] G. Scamps et al., Phys. Rev. C 108, L061602 (2023)