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

229 / 2023-04-17 13:05:27

Measurements of Ultra-Short Lifetime Isomers from Photonuclear Reactions using Laser-Driven Ultra-Intense γ-Ray

Isomer,ultra-short lifetime,photonuclear reaction,laser-driven γ-ray

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

Isomers are a ubiquitous and important population of long-lived nuclear excited states, which play a crucial role in the field of nuclear structures, nuclear reaction mechanisms, and nuclear astrophysics. However, isomers from photonuclear reactions with half-life times of several seconds or less barely had experimental cross section data due to the lack of a suitable measuring method. Here we report a new method of online γ spectroscopy for ultra-short lifetime isomers from photonuclear reactions using the 200-TW-laser-driven ultra-intense γ-ray at Peking University. The fastest time resolution can reach sub-ps level with an instantaneous intensity higher than 10¹⁹/s (≥8 MeV), which is suitable for ultra-short lifetime isomer studies from photonuclear reactions such as (γ, xn), (γ, xp), (γ, α), even (γ, fission). The ¹¹⁵In(γ, n)^114m2In reaction, with a half-life time of 43.1 ms, was first measured in the high energy region which shed light on the nuclear structure studies of In element. This work offered a unique way of gaining insight into photonuclear reaction researches with ultra-short lifetimes and promised an effective way to fill the gap in relevant experimental data.