We have observed cubes of concrete in storage. Those cubes have been activated by neutrons. 

In those cubes we have observed the following radio-elements:

1. Ba 133
2. Co 60
3. Eu 152
4. Eu 154

Below we see the image of ⁶⁰Co activation. The activity is weak (1 MBq is seen from 4m). The activity is present in metallic rods reinforcing the concrete structure. It seems to be mostly present in a block on the background (2nd layer).

The distribution of Europium is quite different, but also mostly in a background block.

Our cameras are uniquely suited to study this kind of low level distributed contaminations.