2nd INFN School and Workshop on “High Power Lasers for Fundamental Science and Applications” (HPLA2025)

Feasibility study of nuclear isomers population mechanisms in laser-generated plasmas

Not scheduled

20m

Aula "Migneco" (Laboratori Nazionali del Sud - Istituto Nazionale di Fisica Nucleare )

Poster Poster Session

Speaker

Angelo Pidatella (Istituto Nazionale di Fisica Nucleare-Laboratori Nazionali del Sud, Catania (IT))

Description

Nuclear isomers – long-lived excited nuclear states – can decouple from thermal equilibrium in stellar plasmas, altering nucleosynthesis flows. Isomers which play a key role in nuclear astrophysics are thereby termed astromers [1], and yet the in-plasma transition and decay rates governing them are poorly constrained in the laboratory. We propose a compact experimental survey, using laser-driven plasmas, to quantify how isomeric states in key isotopes, such as $^{176}$Lu [2,3], are populated and depleted via two competing mechanisms: (a) photoexcitation through intermediate (“doorway”) levels using broadband X-rays [4-6], and (b) in-plasma modified effective nuclear β decay [5] and level-coupling rates during short, intense plasma bursts. We report on our near-term case study on $^{176}$Lu and preliminary schematics of a possible setup to study therein aforementioned reactions. We discuss the relevance of this isotope as well as specifics of the individual processes. The investigation is fully complementary to upcoming studies in the PANDORA facility, where the in-plasma β-decay rate modification will be explored in magnetized electron cyclotron resonance plasmas [7]. We conclude our analysis by expanding on the list of astromers whose thermalization conditions carry some uncertainty and which can benefit from high-precision measurements at laser-based facilities, along with future investigations on exotic processes for isomeric levels thermalization [8,9].

References
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[4] J. Carroll et al. Phys. Rev. C, vol. 43, pp. 1238–1247, 1991.
[5] E. Norman, T. Bertram, S. Kellogg, S. Gil, and P. Wong ApJ, 291, 834–837, 1985.
[6] L. Lakosi, I. Pavlcsek, and A. Veres Acta Phys. Hung., vol. 69, pp. 169–178, 1991.
[7] D. Mascali et al. Universe 8, 80, 2022.
[8] A. Pàlffy, et al. Phys. Rev. Lett. 99, 172502, 2007.
[9] I.N. Izosimov, Laser Phys. 17, 755–759, 2007.