The 6th International Conference on Matter and Radiation at Extremes (ICMRE2023)

21 / 2023-03-29 20:19:51

Isomeric excitation of 229Th in laser-heated clusters

Fundamental Physics at Extreme Light > QED effect and nuclear physics-II

We consider nuclear excitation mechanisms in a ²²⁹Th cluster radiated by an intense femtosecond laser pulse [1]. Two mechanisms are found to be dominant, namely, nuclear excitation by electron capture (NEEC) and nuclear excitation by inelastic electron scattering (NEIES). It is further found that the NEEC mechanism dominates for relatively low intensities \(\approx\) 10¹⁴ W/cm², and the NEIES mechanism dominates for relatively high intensities \(\approx\) 10¹⁶ W/cm². It is possible to control the nuclear excitation mechanism continuously by changing the laser intensity.



This laser-heated-cluster scheme leads to (1) efficient isomeric excitation of the ²²⁹Th nucleus; and (2) an alternative, laser-based, approach for the confirmation of the NEEC process, which has been predicted for over forty years [2] without conclusive experimental verifications [3, 4].



[1] J. Qi, H. Zhang, and X. Wang, Phys. Rev. Lett. 130, 112501 (2023).

[2] V. I. Goldanskii and V. A. Namiot, Phys. Lett. B 62, 393 (1976).

[3] C. J. Chiara et al., Nature 554, 216 (2018).

[4] S. Guo et al., Phys. Rev. Lett. 128, 242502 (2022).