The thing is that if you had average background at 0.09 for a long time and then it suddenly become 0.15 and stay so, this could mean that something happened, despite background is still pretty normal.
Background could vary depending on space weather, but that variations are not permanent and rarely last longer than day. Also, variations in cosmic rays activity influence background radiation levels in wide area, not only in single town.
Again, this change is small and safe, but coincidence of such changes with weapons warehouse blasts attracted my attention.
The thing is that if you had average background at 0.09 for a long time and then it suddenly become 0.15 and stay so, this could mean that something happened, despite background is still pretty normal.
Background could vary depending on space weather, but that variations are not permanent and rarely last longer than day. Also, variations in cosmic rays activity influence background radiation levels in wide area, not only in single town.
Again, this change is small and safe, but coincidence of such changes with weapons warehouse blasts attracted my attention.
In case you were interested:
http://ibb.co/Pg00tmb
The margins of error are high due to short runtimes, the equipment does become confident during longer runs.
Running average helps a lot to lower error margins.