Japanese Soil Tests – First Results

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Soil Sample J-A From Kashiwa City, Chiba Prefecture (26km NE from Tokyo)

Soil Sample J-A From Kashiwa City, Chiba Prefecture (26km NE from Tokyo)

[NOTE: This is not my official results, but a merely my first test of the materials. Much more to come]

I have just received a set of samples from a friend in Japan. The samples are from various locations around the country and ready to be tested in my gamma spectrometer. I will be publishing a full set of tests very soon, but until that time I thought I might provide a small glimpse of the preliminary results. This is a gamma spectrum from a sample, J-A_3600s, which was tested for one full hour using gamma spectroscopy. The sample shown came in a small 1” x 2” canister and contained soil from just under a water rain spout in residential housing area (back yard), of a person living in Kashiwa City, Chiba Prefecture (26km NE from Tokyo).

The sample measured about 306 CPM at contact using a 2” pancake Geiger Muller probe. During the hour of testing, clear photo-peaks for Cesium 134 and 137 were easily detected from the sample. Other features included several very small deformations in the spectrum which were either inconsequential, i.e. x-ray interference, or unidentifiable due to extremely low activity.

The extreme amounts of background “noise” found in the spectrum is consistent with a powerful beta emitter. Gamma spectroscopy cannot directly detect Strontium 90, but given the release amounts of Cs 137 and the typical matching of Cs137 and Sr90 isotopes following a nuclear release, like that of Fukushima, it is plausible to consider that Sr90, and by decay association Y90 and Y90m, are also present.

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