Speaker
Description
Gadolinium (Gd) is a rare earth metal belonging to the lanthanide series. Taking advantage of its large neutron absorption cross section and high $\gamma$-ray energy ($\sim$8 MeV in total) of (n,$\gamma$) reaction, Gd sulfate is dissolved in the Super-Kamiokande (SK) 50 kton water Cherenkov detector, which is being carried out as the SK-Gd project, to increase the detection sensitivity of supernova relic neutrino events.
In this work, the emission characteristics of Gd$^{3+}$ ions in aqueous solution such as quenching by anions and excitation spectra are studied using laser-induced luminescence spectroscopy. A simulation study is performed to estimate the Gd$^{3+}$ emission background rate from cosmic muons in the SK-Gd experiment. We are developing a portable monitoring system based on this spectroscopic technique to enable real-time measurements of Gd$^{3+}$ concentration and emission lifetime without contamination during water sampling.
