Luuk sent me one of his Fukushima soil samples. It is very useful for me because before I didn't have a Cs-137 sample. I can use this to better specify the resolution of my detector-DAQ combination.
The following spectrum is from my new detector (also from Luuk):
Since the sample is not pure Cs-137, and Cs-137 has no coincident gammas, It is interesting to make coincidence measurements to better see what other isotopes are in the sample. I had a second detector in the setup, face-to-face with the first one, and the soil sample sandwiched in between. The coincident matrix looks like this:
In the matrix, I can see two more coincidences that I couldn't find in the table for Cs-134. I have marked them in the following picture of the same matrix (with half the bin size to better see the weak spots). Does anybody know what other isotopes are typically in Fukushima soil sample that could cause these lines?
Michael
