Den 24.04.2018 20:25, skrev mike wilson:
Jostein has a way with Duct tape........
If you can't fix it with duct tape, you haven't used enough duct tape. :-D
On that note, and tuning in with the cellphone theme here, I recently
purchased an app for my phone that, provided you cover the lens with
duct tape, will turn your phone into a quite decent dosimeter.
Apparently it utilises the same effect that had me seriously scared some
six years ago, when I discovered odd streaks of seemingly glowing sensor
dust in long exposure shots with the 645D. And when I looked closer I
found similar black streaks too. Not your ordinary hot pixel, although
some were just dots, one or two pixels wide. And not your ordinary dust
either, as some drew regular spiralling patterns.
In the 645D case, the sensor was just picking up backscatter of cosmic
rays, shattered and bounced by the Earth's crust; which neatly explained
the black streaks as subtracted noise during dark-framing.
The app, however, cranks up the ISO to some unknown overdrive and look
specifically for trails made by alpha and beta particles. Thought that
was pretty neat.
And since there is a known area of Thorium-containing ore an hour's
drive from here, I might now go looking. Duct tape at the ready. :-)
Jostein
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