Speaker
Ming Guan
(Okayama University)
Description
"Thorium-229 has the lowest nuclear excited level (229mTh), around 8 eV, which provides many applications from practical usage to fundamental research. In 2019, our group succeeded in producing 229mTh states via X-ray pumping and in 2023, we observed the vacuum-ultraviolet (VUV) photons stemmed from the radiative decay of 229mTh. The lifetime of 229mTh is measured, by counting the VUV photons, to be around 10^3 seconds after pumping. On the other hand, the lifetime of 229mTh seems quite reduced during the X-ray irradiation. Therefore, the accelerated decay channels of 229mTh during X-ray irradiation exist; isomer quenching."
