[Rpm] [Starlink] On FiWi

[Bruce Perens]

On Fri, Mar 17, 2023 at 1:57 PM rjmcmahon <rjmcmahon at rjmcmahon.com> wrote:

> I'm curious as to why the detectors have to be replaced every 10 years.


Dust, grease from cooking oil vapors, insects, mold, etc. accumulate, and
it's so expensive to clean those little sensors, and there is so much
liability associated with them, that it's cheaper to replace the head every
10 years. Electrolytic capacitors have a limited lifetime and that is also
a good reason to replace the device.

The basic sensor architecture is photoelectric, the older ones used an
americium pelllet that detected gas ionization which was changed by the
presence of smoke. The half-life on the americium ones is at least 400
years (there is more than one isotope, that's the shortest-life one).
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