京都大学実験用原子炉(KUR)を利用した岩石の放射化分析とその問題点

概要

論文の詳細を見る
Instrumental neutron activation analysis of rock samples was carried out using the Research Reactor of Kyoto University (KUR). Twelve rock samples were activated in a capsule together with two samples of JBla, rock reference sample of Geological Survey of Japan. The concentrations of each of elements were calculated using the data of γ-ray intensity, amounts of time of irradiation, cooling and measurement, efficiency of the Ge-detector, and the effective cross section of the atom during the nuclear reaction, γ-ray intensity of Fe-59 (1099keV) from one of the JBla samples was used to normalize the concentration of all other elemets. Another JBla sample in each capsule was used as the working standard. The determined concentration of these JBla samples are compared with the published consensus values. For Na, Sc, Cr, Fe, Co and La, both deviation and inaccuracy are less than 5 %, and for Sm, Eu, Hf, Ta and Th they are less than 10 %. For Ba, Tb, Yb, Lu, Cs and U, deviation is more than 10%. Most of the rock samples were powdered before activation. But crushing the siliceous rock, such as chert, causes the severe problem of contamination from the equipment, so, they were irradiated as pieces of rock fragment.
信州大学理学部の論文
1993-02-26