Development of a method for measuring rare earth elements in the environment for future experiments with gadolinium-loaded detectors

Demand to use gadolinium (Gd) in detectors is increasing in the field of elementary particle physics, especially in neutrino measurements and dark matter searches. Large amounts of Gd are used in these experiments. To assess the impact of Gd on the environment it is becoming important to measure the baseline concentrations of Gd. Such measurement, however, is not easy due to interference by other elements. In this paper a method for measuring the concentrations of rare earth elements, including Gd, is proposed. In the method, inductively coupled plasma-mass spectrometry is utilized after collecting the dissolved elements in chelating resin. Results of the ability to detect anomalous concentrations of rare earth elements in river water samples in the Kamioka and Toyama areas are also reported

Improved method for measuring low-concentration radium and its application to the Super-Kamiokande Gadolinium project

Chemical extraction using a molecular recognition resin named "Empore Radium Rad Disk" was developed to improve sensitivity for the low concentration of radium (Ra). Compared with the previous method, the extraction process speed was improved by a factor of three and the recovery rate for Ra-226 was also improved from 81 +/- 4% to > 99.9%. The sensitivity on the 10(-1) mBq level was achieved using a high-purity germanium detector. This improved method was applied to determine Ra-226 in Gd-2(SO4)(3)center dot 8H(2)O which will be used in the Super-Kamiokande Gadolinium project. The improvement and measurement results are reported in this paper