Flipping around the net after work, I found this article (2014), on the radiation detecting apps that were all the rage back in 2014...well they were for me, I had an Iphone 4S, the app, some black electrical tape and thoriated tungsten tig tips.
This is the Australian ANSTO, testing the apps themselves
http://www.ansto.gov.au/AboutANSTO/MediaCentre/News/ACS049898
Highest background I saw with it was tombstone Arizona on our last trip over there.
This is the Australian ANSTO, testing the apps themselves
http://www.ansto.gov.au/AboutANSTO/MediaCentre/News/ACS049898
Highest background I saw with it was tombstone Arizona on our last trip over there.