Two types of gamma( γ) spectrometer, which detectors are well and broad energy-type, respectively, have been set up in the Earth Science Laboratory. The Well-type γ spectrometer, EGPC 150-P16, has been mainly used for the analysis of lead and cesium, to estimate the sedimentation rate. The Broad Energy (BE)- spectrometer, GX4019, has been mainly applied to the analyses of radium isotopes in water. Both machines effectively measure radioactive elements with a low background noise. The measurement of environmental radioactivity such as 210Pb is usually needed a day and over, though it depends on the amount of activity. Our machines for the radioactivity of ^(210)Pb, Cs, ^(214)Pb, ^(228)Ac are needed at least 1 day. Because of the two busy machines, the coordination using the same sample is requested to keep a better mutual use. We performed the measurement of ^(226)Ra and ^(228)Ra using the same sample and obtained the following result:
For ^(226)Ra: Y_(GX) = 0.00 + 1.00X_(Eu) R^2= 0.94,
and for ^(228)Ra: Y_(GX) = - 0.01 + 1.47X_(Eu) R^2= 0.96,
where Y_(GX) means the content obtained by BE Ge detector, and Y_(Eu) is that of the Well-type Ge detector.