The "Crown of Nobles" Noble Gas Tube Display (2024)

BepiColombo [0] uses 581 kg of Xe gas for its electric propulsion. I remember reading at the time this was being built that it consumed a measurable portion of the global xenon production for that year. This post reminded me to look that up, and it seems to be only ~1% of the ~50 tons, which is quite a bit less than I remember but still quite significant for a single application to use a non-trivial amount of the supply.

[0]https://sci.esa.int/web/bepicolombo/-/60642-bepicolombo-mtm-...

A few safety PSAs on these:

1. This puts out a fair amount of UVC light. Most people are not familiar with this hazard because the atmosphere filters it, but even a modest flux can degrade your eye lenses and give you cataracts. Get a set of safety glasses that explicitly say they block UVC if playing with this for more than a minute or two cumulative. Normally you would use borosilicate glass to filter it, but I would not trust these to use anything other than the cheapest materials.

2. The hazard is "high voltage" but it is 1 MHz, not DC. Conventional wisdoms on DC high voltage insulation isn't sufficient. You need RF safety guidance. If you get your finger within about an inch of the terminals the air will break down and turn your skin into a 50W load. It will smell a lot like burnt plastic, but it is your skin that's been burned. Treat these with respect. They are inherently unsafe because they do not have engineering controls to keep touches away from dangerous locations: a knife with no handle.

In case anyone's wondering: no these aren't really above the level but few enough people are getting hurt and [insert your preferred explanation why society doesn't meet demands] that nothing happens.

Be safe, have fun.

I wonder how this one works: https://youtube.com/watch?v=xlcywgEMuGI

It took some digging to figure out what the debacle was. Is this it? https://vuink.com/post/penool-enguoha-d-dtvguho-d-dvb/mjrath...

A few years with a half-life of less than four days? I doubt you could perceive any glow after more than a few weeks.

In a year the radon would've undergone about a hundred halvings, so around one 10^30th of the original radon nuclei would be left. Which is to say, almost certainly zero. One mole worth of radon would've decayed down to the last atom after less than 300 days (mostly to lead-210, which would then comparatively slowly decay to stable lead-206 with a half-life of about 22 years).