franco_vazza, This is an astrophysics take of the #solarstrom : I have just used the CosmicRay Detector app on my laptop by the Global Cosmic Ray Observatory https://apps.apple.com/us/app/cosmic-ray-detect-radiation/id1169131314
to measure the flux of muons through the blocked shutter of the Ipad.
I don't have stats to compare with, but since I have already done the same experiment in the last two weeks speaking of cosmic ray detection at lecture, I have the feeling the muon flux is a bit higher now (~1 event/second).