Using my SkyCam on the same mast, I was able to correlate a spike in radiation with bursts of intense lightning passing overhead.
It's an SBM-20 tube, sensitive to β and γ. Plastic pretty much blocks β, and this paper abstract (doi.org/10.1038/s415...) indicates it's been observed before.
Tropical thunderclouds over ocean and coastal regions are shown to emit gamma rays for several hours over areas of up to a few thousand square kilometres, contradicting the quasi-stationary picture of...
