While you started speaking of ionisation chambers and now are speaking of flame detectors,
with a neon bulb. Possibly my confusion uh?
Usually I'm the confused one, but it appears that this is definitely your confusion. Post topic
says "fire detection with uv sensor", and the only mention of ionization other than yours was
that Picavr mentioned it in his original post, "detection of fire with uv (ionisation) sensor
Oh well, the neon gas is ionized when the bulb fires, so there is some overlap of thoughts.
If I had to pick, I'd rather there be many million neon bulbs in the landfills than many million
ionization smoke alarms each containing 3 ug of americium-241.