In Germany there is a quite dense official radiation network, that publishes it's data online. The webpage is just in German, but perhaps you'll find it usefull nevertheless:
http://odlinfo.bfs.de/

For Europe there's something similar, but with sometimes a considerably more wide-mashed: EURDEP (EUropean Radiological Data Exchange Platform)


My Sensor here:


And the values from ODL in Neuenlande, ca 3km away from me:

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Gruesse vom Saenger