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.