Figure 3. Activity concentration for 40K in soil samples.

From

Natural Radioactivity in Soil Samples in Nineveh Province and the Associated Radiation Hazards

Laith A. Najam, Shaher A. Younis, Fouzey H. Kithah

International Journal of Physics. 2015, 3(3), 126-132 doi:10.12691/ijp-3-3-6