Numerous particle physics experiments utilize gadolinium (Gd), a rare earth element with the most significant neutron capture cross-section among all elements, to detect anti-neutrinos via inverse beta-decays or to remove neutron-induced background events. For example, to load Gd into water Cherenkov detectors, $\mathrm{ { Gd_{ 2}(SO_{ 4})_{ 3}\cdot 8H_{ 2}O}}$ is dissolved and rare event search experiments are required to screen for radioactive impurities in $\mathrm{ { Gd_{ 2}(SO_{ 4})_{ 3}\cdot 8H_{ 2}O}}$ before dissolution. This study developed a new method to rapidly measure the radium-226($\mathrm{ ^{ 226}Ra}$) concentration in $\mathrm{ { Gd_{ 2}(SO_{ 4})_{ 3}\cdot 8H_{ 2}O}}$. This method requires only three days to measure a batch of samples, as opposed to the usual method using high-purity germanium detectors, which takes approximately 20 days after arrival. The detection limit for the measurement of $\mathrm{ ^{ 226}Ra}$ is 0.32 mBq/kg. This method has been already used for $\mathrm{ { Gd_{ 2}(SO_{ 4})_{ 3}\cdot 8H_{ 2}O}}$ screening at the Super-Kamiokande Gd(SK-Gd) project, and it can be applied to future experiments.
Categories: physics.ins-det