When I was 16 , I worked for the man who invented the smoke detector. I convinced them I was 18 and a HS grad. The name of the corp was BRK corp, Aurora IL. USA. ( later PITTWAY)
The guy was great he kicked my ass, metaphorically speaking, taught me chess. I had a 2nd class RTL ATT
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The schema was a chamber with Americium 243 at 1 end and a lead out to a IGMOSFET with a TERRA ( yup terra) ohm resistor for bias. The Americium ionized the smoke molecules which in turn energized the gate of the FET. The guy was great, looked like Robert Loggia , would eat a sandwich in one hand , turn on a crystal oven and capture my king in 4-5 secs. I remember the experience but not his name The company morphed to First Alert The principles remain the same . I would give anything to show appreciation to him or have extended our relationship, unfortunately as Wilde stated "we are all young and stupid in our lives at one time".
One really cool thing I was involved in ( but did not solve myself) was the problem the detectors had with battery self-policeing..........IIRC when the battery falls below a certain V the alarm should sound. Well the problem was that the level was made statically with TTL.....I figured out that the internal R ( of B+) rose as the V decreased when the detection threshold was exceeded that the alarm couldn't sound as the available V was lower then the alarm ( bicycle horn) needed to signal. This is probably my most significant contrition tho I'm sure it is un recognized or attributed to someone else.
I hope the man lives and his family prospered, he was a father figure to me.